Taking Good Weather Observations

John F Saltenberger Predictive Services Northwest Geographic Area Coordination Center Portland, OR

Preface:

The purpose of taking weather observations during a wildfire or prescribed fire project is to record environmental conditions prevalent at the site. Depending on the size of the project and the complexity of the terrain, several separate weather observation sites may be necessary to adequately convey weather conditions representative of the entire burn site.

Accurate weather observations are important in wildland fire management for several reasons:

1st: Meteorologists build their spot weather forecasts based on the observations reported from the fireline. The forecaster uses the observation to build a mental model of weather pattern in the vicinity of burn site. The more accurate and representative the weather observations are, the more effectively a meteorologist can forecast weather conditions at the site. This results in better fire behavior forecasts. If fireline weather observations are incomplete or unrepresentative, the forecaster will have a much more difficult time accounting for localized effects.

2nd: Meteorologists seek to verify the accuracy of their forecasts by comparing weather conditions observed at the site versus what was forecast. When differences are noted, the meteorologist can potentially learn from the errors and correct for the next forecast. The belt weather kit observation constitutes the best record of weather conditions near the fireline.

3rd: Belt weather kits observations become part of the official fire documentation record. If there is an investigation or litigation following some accident on the fire, belt weather kit observations comprise a key component for re-constructing environmental conditions surrounding the accident. These can prove critical during litigation.

1. Siting

Key Point:

Regardless of whether the fire is a prescribed fire project or a wildfire, the weather observer should strive to pick observation sites that most accurately reflect environmental conditions around the fire’s location.

Tips:

Consider whether to take a weather observation on a ridgetop, midslope or drainage bottom location. Is the fire site exposed or sheltered? What is the aspect and slope? What kind of surface texture? The choice of observation sites should reflect the type of terrain the fire front is most actively burning in. Selecting an unrepresentative site will result in weather observations that don’t truly reflect the environmental conditions of that incident, division or burn site.

Representative fuels

Once safe representative sites have been selected, the weather observer should try to take the observations in the same fuel type the fire is most active in. If the fire is spreading in timber litter, try to take the observations in similar unburned timber. The same is true for brush or grass fuel types.

Minimizing fire influences

The weather observer should avoid taking observations in the black since burned areas tend to be unrepresentatively warm and dry. Attempt to find a safe site upwind of the burned area if at all possible. If the observer has no choice but to take an observation in the black, make sure to note it in the remarks section of the log.

The weather observer should also take care to minimize localized weather effects generated by the fire itself. Take weather observations away from gusty indraft breezes and radiant heat in the vicinity of the flaming front. These are very localized conditions that don’t reflect the area’s general conditions. Generally, well ventilated areas in the shade are desirable spots for belt weather kits to be most effective.

2. Observation process

Key Point:

To be effective, belt weather kits must be properly maintained and operated. Inspect kits for defects prior to each fire assignment. Old, dirty or broken parts should be replaced. Electronic sensors must be calibrated routinely during fire assignments. Proper procedure must be followed to extract the most accurate information from a weather observation.

Tips:

Here are some considerations to keep in mind:

• Check sling psychrometers for separated mercury columns. These can sometimes be corrected by exposing the thermometer to very cool temperatures such as an ice bath.

• Replace dirty wicks on wet bulb thermometers with a clean wick.

• Test the ball in Dwyer wind meters for free movement. Static electrical charge buildup, moisture, or dirt can lodge the ball in the tube.

• Electronic temperature and humidity sensors should regularly be calibrated against weather instruments of reliable accuracy. Check that the batteries are fresh.

• Well maintained sling psychrometers are still the most accurate, durable and reliable indicators of temperature and moisture. They function as well in extreme conditions as in moderate conditions.

Regardless of whether the kit is a traditional sling psychrometer or electronic sensor, get into the habit of letting it acclimatize for several minutes in a shaded, breezy area before beginning an observation. This allows the sensors to gradually adjust to environmental temperature and humidity. Avoid exposing the kit to body heat, sweat, ash, dirt, and direct sunlight. The observer should be careful to store the kit in locations away from temperature extremes such as vehicle dashboards or in line gear pockets.

Avoid direct sunlight during temperature and humidity observation

The wet bulb/dry bulb observation must be taken in shade. Even if the site is grassy (i.e. no shadows from an overstory) the instrument must be protected from direct sunlight. If necessary, the weather observer can use his or her own body shadow to avoid exposing the kit to sunlight.

When using a traditional sling psychrometer, be sure the wick is thoroughly wetted before beginning to swing. Distilled water is preferred. Bottled water is the next best alternative. New wicks may tend to repel water droplets from the wet bulb so the observer may need to gently rub the wick against the side of the water bottle to eliminate air pockets. A soaked wick is the goal.

Continue swinging the sling psychrometer until the wet bulb temperature is reached. This may take several minutes. Continue to check the wet bulb temperature every thirty seconds until it reaches its lowest value. In very dry conditions it may be necessary to re-wet and continue swinging until the lowest value is attained. When the wet bulb temperature ceases descending, the correct value has been reached. Read and record the dry bulb immediately after the lowest wet bulb reading is obtained.

When wet bulb and dry bulb temperature have been determined, compute the dew point and relative humidity using the paper tables included with the kit. Select the appropriate table for the altitude range corresponding to the observation site. Plastic slide rules for computing dew point and humidity should only be used if a printed table is not available. Use of the printed tables will provide greater accuracy.

A time saving strategy is to conduct the wind observation while the temperature sensor is acclimatizing to ambient conditions. Wind observations need not be taken in shade but they should still reflect the ambient conditions affecting the fire.

Points to remember about eye level

wind observations

• The observer should take care to face

directly into the wind and closely observe

the wind speed indicator fluctuations.

Exposure to sunlight is not a concern

during the wind observation.

• An eye level wind speed measurement requires at least one full minute of

sampling and preferably more.

• When using a Dwyer tube, mentally average the wind speed and note the peak gust during the sampling period.

• Electronic sensors make wind averaging easy. They are more accurate and are preferred for eye level wind speed observations.

• Remember: The wind direction is defined as the direction the wind is coming from.

3. Observation logging and remarks

Key Point:

Careful record keeping is as important to the weather observation process as every other step. It’s a good idea for the observer to double check recorded values for obvious errors before logging and submitting.

Tips:

Effective logging

Carefully note the date, time and location of each weather observation. Include aspect, elevation, exposure and fuel type whenever possible. If the observer is changing locations, this becomes even more important.

Don’t confuse the wet bulb, dry bulb and dewpoint temperatures. Double check to insure the proper values are noted in their respective columns of the observation form. Use clear penmanship. This is a frequent source of error.

Compare the latest weather observation against those taken during previous hours. Stay alert for any obvious discrepancies. Weather conditions naturally fluctuate during the course of a day but large changes may indicate either a significant weather event or an instrument malfunction. To reduce potential errors, it is a good idea to cross check weather observations with nearby observers.

Best use of the remarks column

The remarks column can be used to log significant features such as:

• Alto-cumulus clouds, cumulus buildups or thunderstorms • Lightning • Smoke column developing a pyro-cumulus cap cloud • Lenticular clouds • Sudden wind shifts • Changing cloud cover • Dust clouds radiating away from downdraft impacts • Inversions • Dust devils • Showers or virga • Upper level winds significantly different than surface winds • Other significant features since last observation Lastly, it’s a good idea to remark whether the observations were made with an electronic weather sensor or traditional sling psychrometer.

4. Transmission of observations

Key Point:

The most accurate weather observation is of little use unless it is properly received by those who need its information. The weather observer should make sure that the chain of communication is functioning rapidly and efficiently at both ends.

Tips:

Plan to transmit

Work out a plan to transmit weather observations to the Incident Communications Unit or local fire dispatch office on a regular schedule as necessary. Double check that each observation has been received clearly by asking to have it repeated back. This technique is effective at reducing errors.

Remember that weather observations may need to be recorded and transmitted more than once per hour. Fast breaking weather changes can endanger firefighter safety so be ready to act rapidly when the situation requires.

It’s a good idea make sure the observation is being properly relayed to the Incident Meteorologist, weather office, or other affected users. This is particularly true during critical burning conditions or significant weather changes. Don’t assume that weather observations are automatically being received by the proper users. The weather observer may need to take the initiative to verify that the information is being passed up the line.

Weather Factors Chapter 7

The average temperature change throughout the lower The material in chapter 7 describes weather atmosphere over time and space is about 5.5 °F per 1,000 factors that firefighters encounter in predicting fire feet for dry weather. Average temperature varies with behavior. These factors include dry and wet bulb humidity. temperatures, dew point, and relative humidity. Example 1—At an elevation of 1,800 feet on Mt. Tampico, the dry bulb temperature is 76 °F. The wet bulb 7.1 Dry Bulb Temperature Dry bulb temperature is temperature is 50 °F. What is the dew point temperature the ambient temperature. It is measured in degrees, from and the relative humidity? a mercury thermometer with a scale of Fahrenheit or Celsius in an area away from direct sunlight. Step 1. Select the proper table for the elevation in question. See figure 7.1.

7.2 Wet Bulb Temperature Wet bulb temperature is Step 2. Find the wet bulb temperature of 50 °F at the top the lowest temperature to which the current air can be of the table, and then move down the column. cooled. Cooling is achieved by evaporating water into air at a constant pressure. Wet bulb temperature is measured Step 3. Find the dry bulb temperature of 76 °F at the left by a psychrometer. The greater the difference is between side of the table, and then move horizontally to the right. wet and dry bulb temperatures, the drier the air is. Step 4. Find the intersection of the wet bulb temperature column and dry bulb temperature row. 7.3 Dew Point Dew point is the temperature to which air must be cooled to reach its saturation point. This must Step 5. Read the two numbers. The lower number in the be done at a constant pressure and moisture content. A block is the relative humidity; the upper number is the dew rising dew point indicates increasing moisture. point temperature.

The dew point is 14 °F and the 7.4 Relative Humidity Relative humidity is the relative humidity is 9 percent. amount of moisture in the air that is in the form of water vapor. Fully saturated air is fog. Relative humidity is always expressed as a percentage. Example 2—The wet bulb temperature is 55 °F and the dry bulb temperature is 68 °F. The expected high for the Once the dry and wet bulb temperatures have been day is 90 °F. What will the relative humidity be when the measured, the dew point and relative humidity can be temperature is 90 °F? determined with the use of tables. See figure 7.1 for use at elevations between 501 and 1,900 feet above sea level. Step 1. Find the dew point. See figure 7.1. The dew point is 45 °F. Relative humidity will change with temperature, whereas the dew point will remain nearly the same. This fact can Step 2. Go to the dry bulb temperature of 90 °F, and move be used to determine the minimum relative humidity for horizontally to the right until the block with the same dew the afternoon, using the predicted high temperature for the point of 45 °F is found. On the chart only 44 °F and 47 °F day and the observed dew point. are shown as the two closest dew points to 45 °F.

Step 3. Read the relative humidity from both squares. 20 and 22.

85 Chapter 7 Weather Factors

Step 4. Take an average of the two numbers. 20 + 22 = 42 = 21 22

Relative humidity is 21percent with a temperature of 90 °F.

Example 3—The observed temperature at 3,000 feet is 87 °F. What is the projected temperature at 5,000 feet?

Step 1. Find the change in elevation. 5,000 feet Ð 3,000 feet = 2,000 feet

Step 2. For every 1,000 foot gain in elevation there is a 5.5 °F temperature drop.

2,000 ft 5.5° = 11° 1,000 ft

87 °F Ð 11 °F = 76 °F

86 For use at elevations between 86 87 88 89 90 501 and 1,900 feet above sea level

DP = Top number RH = bottom number

79 80

Ex2

2 4 6 8 10 12 14 16 18 20 22 25 27 29 32 34 37 39 42 45 47 50 53 56 59 62 65 68 71 75 78 82 85 89 92 96 100

2 4 6 8 10 12 14 16 19 21 23 26 28 30 33 35 38 41 43 46 49 52 55 58 61 64 67 71 74 78 81 85 88 92 96 100

1 3 5 7 9 11 13 15 17 19 22 24 26 29 31 34 36 39 41 44 47 50 52 55 58 61 65 68 71 74 78 81 85 88 92 96 100

-19 -1 +10 17 23 28 32 36 39 42 45 48 50 52 55 57 59 61 62 64 66 68 69 71 72 74 76 77 78 80 81 83 84 85 86 88 89

-37 -7 +6 14 21 26 30 34 38 41 44 47 49 52 54 56 58 60 62 64 66 67 69 71 72 74 75 77 78 79 81 82 84 85 86 87 89 90

2 4 6 8 10 12 15 17 19 22 24 26 29 32 34 37 40 42 45 48 51 54 57 60 64 67 70 74 77 81 84 88 92 96 100

1 3 5 7 9111316182022252730323537404346495154586164677074778185889296100

-12 +2 11 18 24 28 32 36 39 42 45 48 50 52 54 57 59 60 62 64 66 67 69 71 72 74 75 77 78 79 81 82 83 85 86

-24 -3 +8 16 22 27 31 35 38 41 44 47 49 52 54 56 58 60 62 64 65 67 69 70 72 73 75 76 78 79 80 82 83 84 86 87

-50 -10 +4 13 19 25 29 33 37 40 43 46 48 51 53 55 57 59 61 63 65 66 68 70 71 73 74 76 77 79 80 81 83 84 85 87 88

2 4 6 8 10 13 15 17 20 22 25 27 30 33 35 38 41 44 47 50 53 56 59 63 66 70 73 77 80 84 88 92 96 100

1 3 5 7 9 11 14 16 18 21 23 26 28 31 33 36 39 42 45 47 50 54 57 60 63 66 70 73 77 81 84 88 92 96 100

-15 +1 10 17 23 27 32 35 38 41 44 47 49 52 54 56 58 60 62 63 65 67 68 70 71 73 74 76 77 79 80 81 83 84

-29 -5 +7 14 21 26 30 34 37 40 43 46 48 51 53 55 57 59 61 63 65 66 68 69 71 73 74 76 77 78 80 81 82 84 85

2 4 6 8 10 13 16 18 21 23 26 28 31 34 37 40 43 46 49 52 55 59 62 65 69 73 76 80 84 88 92 96 100

1 3 5 7 912141719212427293235384043464953565962666973768084889296100

-18 -1 +9 16 22 27 31 34 38 41 44 46 49 51 53 55 57 59 61 63 64 66 68 69 71 72 74 75 77 78 79 81 82

-34 -7 +5 13 20 25 29 33 36 40 43 45 48 50 52 54 56 58 60 62 64 66 67 69 70 72 73 75 76 78 79 80 82 83

3 5 8101315182023262932353841444750545761646872757983879196100

2 4 6 9 11 14 16 19 21 24 27 30 32 35 38 41 45 48 51 54 58 61 65 68 72 76 79 83 87 92 96 100 81 82 83 84 85

1 3 5 7 10 12 15 17 20 22 25 28 30 33 36 39 42 45 48 51 55 58 62 65 69 72 76 80 84 88 92 96 100

Ex1

-21 -2 +8 15 21 26 30 34 37 40 43 45 48 50 52 54 56 58 60 62 64 65 67 69 70 72 73 75 76 77 79 80

-40 -9 +4 12 19 24 28 32 36 39 42 45 47 49 52 54 56 58 60 61 63 65 67 68 70 71 73 74 76 77 78 80 81

Wet bulb temperatures Wet

3 5 8 10 13 16 18 21 24 27 30 33 36 39 43 46 49 53 56 60 63 67 71 75 79 83 87 91 96 100

1 4 6 91114171922252831343740434650535760646771757983879196100

-23 -4 +7 14 20 25 29 33 36 39 42 45 47 50 52 54 56 58 60 61 63 65 66 68 69 71 72 74 75 77 78

-48-11+31118232832353841444649515355575961636466676971727375767879

1 4 7 9 12 15 17 20 23 26 29 32 35 39 42 45 49 52 56 59 63 67 71 75 79 83 87 91 96 100

3 5 811131619222528313538414448515559626670747882879195100767778

-25 -5 +6 14 20 24 29 32 36 39 42 44 47 49 51 53 55 57 59 61 62 64 66 67 69 70 72 73 75 76

-57 -12 +2 10 17 22 27 31 34 38 41 43 46 48 50 53 55 57 58 60 62 64 65 67 68 70 71 73 74 76 77

-13 +1 10 16 22 26 30 34 37 40 43 45 48 50 52 54 56 58 60 61 63 65 66 68 69 71 72 74 75

3 5 8 111417202326303336404347505558626569747882869195100

1 4 710121518212427303437404447515458626670747882879195100

-140+916212630333639424547495153555759616264666769707273

-27 -6 +5 13 19 24 28 32 35 38 41 44 46 48 51 53 55 57 58 60 62 64 65 67 68 70 71 73 74

3 6 9 1215182124283134384245495357606569737782869195100

1 4 7 101316192225293235394246505357616569737782869195100

-150+9152125293336394244464951535557586062636567687071 -28 -6 +5 12 18 23 28 31Ex1 35 38 40 43 46 48 50 52 54 56 58 60 61 63 65 66 68 69 71 72

3 6 912161922262933364044475155596468727781869095100

1 4 710141720232730343741444852566064687277818690951007172737475

-15 -1 +8 15 20 25 29 32 35 38 41 44 46 48 50 52 54 56 58 60 61 63 65 66 68 69

-29 -7 +4 12 18 23 27 31 34 37 40 43 45 47 50 52 54 55 57 59 61 62 64 66 67 69 70

3 6 10 13 16 20 23 27 31 34 38 42 46 50 54 58 63 67 71 76 80 85 90 95 100

2 5 8 11141821242832353943475155596367727681859095100

-15 -1 +8 15 20 24 28 32 35 38 41 43 46 48 50 52 54 56 57 59 61 62 64 66 67

-29 -7 +4 12 18 22 27 30 34 37 40 42 45 47 49 51 53 55 57 59 60 62 63 65 67 68

3 7 10 14 17 21 25 29 32 36 40 44 48 53 57 61 66 70 75 80 85 90 95 100 66 67 68 69 70

2 5 8 121519222630333741454953586266717680859095100

-15 -1 +8 14 20 24 28 32 35 38 40 43 45 47 49 51 53 55 57 59 60 62 63 65

-28 -7 +4 11 17 22 26 30 33 36 39 42 44 46 49 51 53 54 56 58 60 61 63 64 66

4 7 11 15 19 22 26 30 34 38 43 47 51 56 60 65 70 74 79 84 89 95 100

2 5 9 1216202427313539434852566165707580859095100

70 -27 -7 +4 11 17 22 26 30 33 36 39 41 44 46 48 50 52 54 56 58 59 61 62 64 Dry bulb temperatures

2 6 10 13 17 21 25 29 33 37 42 46 50 55 60 64 69 74 79 84 89 95 100

-25 -6 +4 11 17 22 26 30 33 36 38 41 43 46 48 50 52 54 55 57 59 60 62 -58 -14 -1 +8 14 20 24 28 31 34Ex2 37 40 42 45 47 49 51 53 55 57 58 60 61 63 1 4 812162024283236414550545964697479848995100 Figure 7.1—Relative humidity and dew point table, (Psychrometric.)

39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

-50 -14 -1 +8 14 19 24 28 31 34 37 40 42 44 47 49 51 53 54 56 58 59 61 87

65 Chapter 7 Weather Factors

EXERCISES

Problem 1. Lupe is at an elevation of 1,000 feet. The dry bulb temperature is 80 °F. The wet bulb temperature is 52 °F. What is the relative humidity and the dew point?

Problem 2. What is the relative humidity if the wet bulb temperature is 47 °F and the dry bulb temperature is 64 °F?

Problem 3. Vivian is trying to determine what the minimum relative humidity will be at 1600 hours. She is at an elevation of 1,200 feet. The current dry bulb temperature is 67 °F. The wet bulb temperature is 56 °F. The predicted temperature for the afternoon is 80 °F.

88 Fuels for Fire Behavior Chapter 8

may produce firebrands. Some pinyon-juniper may be in The material in chapter 8 describes fuel models for this model. fire behavior variables, including fine dead fuel moisture and live fuel moisture. Fuel Model 3 (2.5-feet deep) Fires in this fuel are the most intense of the grass group and display high rates of spread under the influence of wind. Fire may be driven 8.1 Fuel Models A fuel model is a preliminary into the upper heights of a grass stand by wind and may representation of vegetation characteristics used in cross over standing water. Stands are tall, averaging analyzing fire behavior and planning. The models provide about 3 feet, but considerable variation may occur. wildland firefighters with a common way of describing Approximately one-third or more of the stand is fuels in the area. considered dead or cured, maintaining the fire.

There are two sets of fuel models, a set designated with numbers for the Fire Behavior Prediction System (FBPS) The Shrub Group—Fuel Models 4, 5, 6, and 7 and a set designated with letters for the National Fire Danger Rating System (NFDRS). Thirteen fuel models Fuel Model 4 (6-feet deep) Fire intensity and fast associated with fire behavior are described in this chapter. spreading fires involving foliage and live and dead fine They are subdivided into the Grass, Shrub, Timber Litter, woody materials in the crowns of a nearly continuous and Logging Slash Groups. These descriptions provide secondary overstory characterize Fuel Model 4. insight into various components of the fuel model that Examples are stands of mature shrub 6-or-more-feet tall, have the potential to carry the fire spread. Choosing such as California mixed chaparral, high pocosins along appropriate fuel models requires experience and sound the east coast, pine barrens of New Jersey, or the closed personal judgment. See figure 8.4. jack pine stands of the north central States. Besides flammable foliage, there is dead woody material in the stand that significantly contributes to fire intensity. Heights The Grass Group—Fuel Models 1, 2, and 3 of stands qualifying for this model vary with local conditions. There may also be a deep litter layer that Fuel Model 1 (1-foot deep) Fire spread in Fuel Model 1 is compounds suppression efforts. governed by fine herbaceous fuels that are cured or nearly cured. Surface fires move rapidly through cured Fuel Model 5 (2-feet deep) Fire generally is carried in grass and associated material. Very little shrub or timber is surface fuels composed of litter cast by shrubs and present, generally in less than one-third of the area. grasses, or forbs, in the understory. Fires generally lack Grasslands and savanna are represented, along with intensity as surface fuel loads are light, shrubs are young stubble, grass tundra, and grass shrub combinations that with little dead material, and foliage contains little volatile meet the above area constraint. Annual and perennial material. Shrubs generally are not tall, but nearly cover grasses are included in this fuel model. the entire area. Examples are young green stands with little or no deadwood, such as laurel, vine maple, alder, or Fuel Model 2 (1-foot deep) Fire spread in Fuel Model 2 is even chaparral, manzanita, or chamise. As shrub fuel primarily through fine herbaceous fuels, either curing or moisture drops, consider using Fuel Model 6. dead. These are surface fires where the herbaceous material, besides litter and dead-down stemwood from the Fuel Model 6 (2.5-feet deep) Fires carry through the open shrub or timber overstory, contribute to the fire shrub layer where foliage is more flammable than Fuel intensity. Open shrub lands, pine stands, or scrub oak Model 5, but require moderate winds, greater than 8 miles stands that cover one-third to two-thirds of the area, per hour, at midflame height. Fire will drop to the ground generally fit this model. However, they may include at low windspeeds or openings in the stand. Shrubs are clumps of fuels that generate higher fire intensities and older, but not as tall as shrub types of Model 4, nor do

89 Chapter 8 Fuels for Fire Behavior they contain as much fuel as Model 4. A broad range of Fuel Model 10 (1-foot deep) The fires in this model burn shrub conditions are covered by this model. Typical in surface and ground fuels with greater fire intensity than examples include intermediate stands of chamise, in other timber litter models. Dead-down fuels include chaparral, oak brush, low pocosin, Alaskan spruce taiga, greater quantities of 3-inch or larger limb wood, resulting and shrub tundra. Cured hardwood slash can be from over-maturity or natural events that create a large considered. Pinyon-juniper shrub-lands may fit, but may load of dead material on the forest floor. Crowning out, overpredict the rate of spread, except at high winds, for spotting, and torching of individual trees are more frequent example 20 miles per hour at the 20-foot level. in this fuel situation, leading to potential fire control difficulties. Any forest type may be considered when Fuel Model 7 (2.5-feet deep) Fire burns through the heavy-down materials are present. Examples are insect- surface and shrub strata equally. Fire can occur at higher infested or diseased stands, wind-thrown stands, or over- dead fuel moisture contents due to the flammable nature mature situations with deadfall, cured light thinning, or of live foliage. Shrubs are generally 2 to 6 feet high. partial-cut slash. Examples are Palmetto-gallberry understory-pine overstory sites, low pocosins, and Alaska black spruce shrub combinations. The Logging Slash Group—Fuel Models 11, 12, and 13

Fuel Model 11 (1-foot deep) Fires are fairly active in slash The Timber Litter Group—Fuel Models 8, 9, and 10 and herbaceous material intermixed with slash. Spacing of a rather light fuel load, shading from overstory, or aging of Fuel Model 8 (0.2-foot deep) Slow burning ground fires fine fuels can contribute to limiting fire potential. Light with low flame heights are common to this fuel model, partial cuts or thinning operations in mixed conifer stands, although an occasional “jackpot,” or heavy fuel hardwood stands, and southern pine harvests are concentration, may cause a flareup. Only under severe considered representative. Clear cut operations generally weather conditions do these fuels pose fire problems. produce more slash than represented here. The less than Closed-canopy stands of short-needle conifers or 3-inch material load is smaller than 12 tons per acre. The hardwoods that have leafed out support fire in the less than 3-inch material is represented by not more than compact litter layer. This layer is mainly needles, leaves, 10 pieces, 4 inches in diameter, along a 50-foot transect. and some twigs, since little undergrowth is present in the stand. Representative conifer types are white pine, lodge- Fuel Model 12 (2.3-feet deep) Rapidly spreading fires pole pine, spruce, true firs, and larches. with high intensities capable of generating firebrands can occur. When fire starts, it is generally sustained until a fuel Fuel Model 9 (0.2-foot deep) Fires run through surface break or change in fuels is encountered. The visual litter faster than in Model 8 and have a higher flame impression of these stands is one dominated by slash, height. Both long-needle conifer and hardwood stands, much of it less than 3 inches in diameter. These fuels total especially the oak hickory types, are typical. Fall fires in less than 35 tons per acre and seem well distributed. hardwoods are representative, but high winds will actually Heavily thinned conifer stands, clear cuts, and medium or cause higher rates of spread than predicted because of heavy partial cuts are represented. The less than 3-inch spotting caused by rolling and blowing leaves. Closed material is represented by encountering 11 pieces, 6 stands of long-needled pine, such as ponderosa, Jeffrey, inches in diameter, along a 50-foot transect. red pines, or southern pine plantations, are grouped in this model. Concentrations of dead-down woody materials will Fuel Model 13 (3-feet deep) Fire is generally carried by a contribute to possible torching out of trees, spotting, and continuous layer of slash. Large quantities of greater than crowning activity. 3-inch material are present. Fires spread quickly through fine fuels, and the intensity builds up as large fuels start

90 Fuels for Fire Behavior Chapter 8 burning. Active flaming is sustained for long periods, and a slope. In addition, each table references different months wide variety of firebrands can be generated. Firebrands of the year. contribute to spotting problems as weather conditions become more severe. Clear cut and heavy partial cuts in Table 8.2 provides the correction for the months of May, mature and over-mature stands occur where the slash June, and July between the hours of 0800 and 1959. load is dominated by less-than-3-inch material. The total Table 8.3 is for the months of February, March, April, load may exceed 300 tons per acre, but the less-than-3- August, September, and October between the hours of inch fuel is generally only 10 percent of the total load. 0800 and 1959. Table 8.4 is for the months of November, Situations where slash still has “red” needles attached, but December, and January between the hours of 0800 and the total load is lighter, such as a Model 12, can be 1959. Notice that the time is given in military time. Military represented because of an earlier higher fire intensity and time is based on 24 hours, i.e., 2400 is midnight, 0100 is faster rate of spread. 1:00 a.m., 1200 is noon, and 1400 is 2:00 p.m.

8.2 Fuel Moisture Content Fuel moisture content is Each table has a top section indexed for unshaded the amount of water in fuel, expressed as a percent of the surface fuels by daytime hour and a bottom section for oven-dry weight of that fuel. If no moisture was in a fuel, shaded surface fuels. Each section is further indexed by as if it was dried in an oven, the fuel moisture content relative location, A for 1,000 to 2,000 feet above the site would be zero. Fuel moisture content can be estimated in location, B for 1,000 to 2,000 feet below, and L for 0 to the field by using fuel moisture tables. Fuel moisture plays 1,000 feet above or below the site location. a significant role in determining how quickly a fire will spread. Corrections for aspect and percent slope are presented on the left side of the table. Referencing the appropriate Fine Dead Fuel Moisture—Dead fuel moisture in fuels values, the intersection of the row and column will indicate ranges from about 2 to 30 percent. Fine dead fuel the appropriate fuel moisture correction value. moisture fluctuates considerably over time due to environmental factors. Tables can provide acceptable Fine Dead Fuel Moisture Worksheet, Figure 8.1 estimates of 1-hour time-lag fine dead fuel moistures All of the necessary data for the fine dead fuel moisture under a variety of conditions. To determine the adjusted calculation is recorded in the Fine Dead Fuel Moisture fine dead fuel moisture (FDFM), add the reference fuel Worksheet. The input values are all of the data that is moisture (RFM) and the fuel moisture correction value used to compute the final answer or output value. This (FMC). RFM and FMC values are obtained from tables guides the process, and the addition is performed at the referenced by analysis of specific conditions. conclusion of the data collection.

Reference Fuel Moisture, Table 8.1 Example 1—It is October 1, at 1300. Fuels are exposed To read a value for reference fuel moisture, the dry bulb to the sun on a west aspect. Readings from a belt weather temperature and relative humidity of the site must be kit taken 1,500 feet above the fire give a dry bulb known. Temperature range is on the left and humidity is temperature of 93 °F and a relative humidity of 17 percent. on the top of the table. Once the appropriate range for The slope is 45 percent. What is the fine dead fuel both items is chosen, find where the temperature row and moisture content? humidity column intersect. At the intersection, there is a RFM content percent. Note this number. Step 1. Enter all the data values given into the worksheet. See figure 8.1. Dead Fuel Moisture Content Correction, Tables 8.2, 8.3, and 8.4 Step 2. According to table 8.1 the reference fuel moisture Three tables are used for correcting dead fuel moisture (RFM) has an index of 2. Put the result on line 6 of the content, based on shaded or unshaded surface fuels, worksheet. hour during the day, relative location, aspect, and percent

91 Chapter 8 Fuels for Fire Behavior

Table 8.1—Reference Fuel Moisture, Day (0800 to 1959) (Input Line 6)

Dry Relative Humidity (Percent) Bulb 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Temp ▼▼ ▼▼▼ ▼▼▼ ▼ ▼▼▼▼▼▼▼ ▼▼ ▼▼100 (°F) 4 9 14 19 24 29 34 39 44 49 54 59 64 69 74 79 84 89 94 99 10-29 1 2 2 3 4 5 5 6 7 8 8 8 9 9 10 11 12 12 13 13 14 30-49 1 2 2 3 4 5 5 6 7 7 7 8 9 9 10 10 11 12 13 13 13 50-69 1 2 2 3 4 5 5 6 6 7 7 8 8 9 9 10 11 12 12 12 13 70-89 1 1 2 2 3 4 5 5 6 7 7 8 8 8 9 10 10 11 12 12 13 90-109 1 1 2 2 3 4 4 5 6 7 7 8 8 8 9 10 10 11 12 12 13 109+ 1 1 2 2 3 4 4 5 6 7 7 8 8 8 9 10 10 11 12 12 12 Go to table 8.2, 8.3, or 8.4 for Fuel Moisture Content Corrections

Table 8.2—Dead Fuel Moisture Content Correctons Day (0800 to 1959) May, June, July (Input Line 13)

Unshaded—Less than 50% shading of surface fuels 0800> 1000> 1200> 1400> 1600> 1800> Aspect % slope B L AB L A B L AB L A B L A BL A 0-30 2 3 4 1 1 1 0 0 1 0 0111 1 234 N 31+3441 221 1211212 2 344 0-30 2 2 3 1 1 1 0 0 1 0 0111 2 344 E 31+1220 010 0111223 4 456 0-30 2 3 3 1 1 1 0 0 1 0 0111 1 233 S 31+2331 120 1101111 2 233 0-30 2 3 4 1 1 2 0 0 1 0 0101 1 233 W 31+4562 341 1200100 1 122 Shaded—50% or more shading of surface fuels N all4553 453 3433434 5 455 E all4453 453 3434434 5 456 S all4453 453 3433434 5 455 W all4563 453 3433434 5 445

Note: when using tables 8.2, 8.3, and 8.4: B = 1,000 to 2,000 feet below the site location L = 0 to 1,000 feet above or below the site location A = 1,000 to 2,000 feet above the site location

92 Fuels for Fire Behavior Chapter 8

Table 8.3—Dead Fuel Moisture Content Corrections Day (0800 to 1959) February, March, April, August, September, October (Input Line 13)

Unshaded—Less than 50% shading of surface fuels

Aspect % slope 0800> 1000> 1200> 1400> 1600> 1800> B LABLA BLAB LABL A BLA N 0-30 3 4 5 1 2 3 1 1 2 1 1 2 1 2 3 3 4 5 31+3 45334 2342 34334 345 E 0-30 3 4 5 1 2 3 1 1 1 1 1 2 1 2 4 3 4 5 31+3 44111 1111 23345 456 S 0-30 3 4 5 1 2 2 1 1 1 1 1 1 1 2 3 3 4 5 31+3 45122 0110 11122 345 W 0-30 3 4 5 1 2 3 1 1 1 1 1 1 1 2 3 3 4 5 31+4 56344 1331 11111 334 Shaded—50% or more shading of surface fuels N all4 56455 3453 45455 456 E all4 56345 3453 45456 456 S all4 56345 3453 45345 456 W all4 56455 3453 45345 456 Note: when using tables 8.2, 8.3, and 8.4: B = 1000 to 2000 feet below the site location L = 0 to 1000 feet above or below the site location A = 1000 to 2000 feet above the site location

Table 8.4—Dead Fuel Moisture Content Corrections Day (0800 to 1959) November, December, January (Input Line 13)

Unshaded—Less than 50% shading of surface fuels Aspect % slope 0800> 1000> 1200> 1400> 1600> 1800> B LABLA BLAB LABL A BLA N 0-30 4 5 6 3 4 5 2 3 4 2 3 4 3 4 5 4 5 6 31+4 56456 4564 56456 456 E 0-30 4 5 6 3 4 4 2 3 3 2 3 3 3 4 5 4 5 6 31+4 56234 2233 44456 456 S 0-30 4 5 6 3 4 5 2 3 3 2 2 3 3 4 4 4 5 6 31+4 56233 1121 12233 456 W 0-30 4 5 6 3 4 5 2 3 3 2 3 3 3 4 4 4 5 6 31+4 56456 3442 23234 456 Shaded—50% or more shading of surface fuels N all4 56456 4564 56456 456 E all4 56456 4564 56456 456 S all4 56456 4564 56456 456 W all4 56456 4564 56456 456 Note: when using tables 8.2, 8.3, and 8.4: B = 1,000 to 2,000 feet below the site location L = 0 to 1,000 feet above or below the site location A = 1,000 to 2,000 feet above the site location 93 Chapter 8 Fuels for Fire Behavior

Table 8.5—Reference Fuel Moisture Night (2000 to 0759)

Dry Relative Humidity (Percent) Bulb 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Temp ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ 100 (°F) 4 9 14 19 24 29 34 39 44 49 54 59 64 69 74 79 84 89 94 99 10-29 1 2 4 5 5 67891011121214151719222525+25+ 30-49 1 2 3 4 5 6789 911111213141618212425+25+ 50-69 1 2 3 4 5 6688 910111112141617202325+25+ 70-89 1 2 3 4 4 5678 910101112131517202325+25+ 90-109 1 2 3 3 4 5678 9910101113141619222525+ 109+ 1 2 2 3 4 5668 899101112141619212425+

Table 8.6—Dead Fuel Moisture Content Correctons Night (2000 to 0759)

2000> 2200> 0000> 0200> 0400> 0600> Aspect BLABLABLABLABLABLA N + E 9 1 1 13 1 2 16 2 2 17 1 1 18 1 1 16 2 1 S + W 9 0 1 14 0 1 16 0 2 17 0 1 18 0 0 9 0 1

Note: B = 1,000 to 2,000 feet below the site location L = 0 to 1,000 feet above or below the site location A = 1,000 to 2,000 feet above the site location

94 Fuels for Fire Behavior Chapter 8

Fine Dead Fuel Moisture Worksheet

Input 0 Projection point ______Ex 1 ______Prob 5 _____ 1 Daytime calculation ______DDD ______2 Dry bulb temperature, °F ______99 _____ 3 Wet bulb temperature, °F ______4 Dew point, °F ______5 Relative humidity, % ______17 ______12 _____ 6 Reference fuel moisture (RFM), % ______22 ______(from table 1) 7 MonthOctober ______July _____ 8 Unshaded (U) or shaded (S) (Circle)______U/S ______U/S _____ U/S 9 Time ______1300 ______1500 _____ 10 Elevation change (Circle) ______B/L/A ______B/L/A _____ B/L/A B = 1,000 to 2,000 feet below site L = ±1,000 feet of site location A = 1,000 to 2,000 feet above site 11 Aspect (N, E, S, W) ______West ______West _____ 12 Slope, % ______45 ______42 13 Fuel moisture correction (FMC), % ______30 ______(from table 2, 3, or 4)

Output 1 Fine dead fuel moisture (FDFM), % ______52 ______(line 6 + line 13)

Figure 8.1—Fine dead fuel moisture worksheet.

95 Chapter 8 Fuels for Fire Behavior

Step 3. On table 8.3 a dead fuel moisture content 8.4 Determining Fuel Size Fuels can be assumed to correction (FMC) of 3 is read. Put the result on line 13 of have a circular cross sectional area. Consequently, the the worksheet. diameter can be estimated from the cut section. See figure 8.3. Step 4. Add these two together (RFM + FMC = FDFM), FDFM = 5. Put the answer in line 1 of the output on the worksheet.

8.3 Live Fuel Moisture Oven drying and weighing 1/16” 1/8” 3/16” 1/4” 5/16” 3/8” 7/16” 1/2” procedures can accurately determine live fuel moisture content, but fire considerations are usually satisfied with a Figure 8.3—Diameter key. good estimate. Live fuel moisture is estimated from figure 8.2, which provides moisture percentages for fuels at different stages of vegetative development. Fuel Loading Approx. Moist. Live Fuel Moisture Fuel 1- 10- 100- Fuel Bed of ROS FL % Moisture Model hour hour hour Live Depth Ext. (ch/h) (ft) (ft) (%) Stage of vegetative development content Grass Group 1 X 1.0 12 78 4 Fresh foliage, annuals developing early in 300 2 X X X X 1.0 15 35 6 growing cycle 3 X 2.5 25 104 12 Shrub Group Maturing foliage, still developing with 200 4 X X X X 6.0 20 75 19 full turgor 5 X X X 2.0 20 18 4 6 X X X 2.5 25 32 6 Mature foliage, new growth complete and 100 7 X X X X 2.5 40 20 5 comparable to older perennial foliage Timber Litter Group 8 X X X 0.2 30 2 1 Entering dormancy, coloration starting, 50 9 X X X 0.2 25 8 3 some leaves may have dropped from stem 10 X X X X 1.0 25 8 5 Completely cured Less than 30, Logging Slash Group treat as a 11 X X X 1.0 15 6 4 dead fuel 12 X X X 2.3 20 13 8 13 X X X 3.0 25 14 11 Figure 8.2—Live fuel moisture approximations. Figure 8.4—Fuel model size class key.

A method for calculating these percentages is governed by the following equation: Moisture Content (MC) = Net Wet Weight Ð Net Dry Weight x 100 Net Dry Weight

96 Fuels for Fire Behavior Chapter 8

EXERCISES

Problem 1. What is the reference fuel moisture (RFM) at a temperature of 89 °F and a relative humidity of 23 percent?

Problem 2. What is the reference fuel moisture (RFM) at a temperature of 67 °F and a relative humidity of 67 percent?

Problem 3. What is the fuel moisture correction (FMC) for May 21, at 1330 with a south aspect and 19 percent slope in a clear unshaded area for elevations B, L, and A?

Problem 4. What is the fuel moisture correction (FMC) for August 12, at 0830 with a north aspect in cloudy skies (shaded fuel) on a 44° slope for elevations B, L, and A?

Problem 5. It is July 19, at 1500. Fuels are exposed to the sun on a west aspect. Readings from a belt weather kit taken 600 feet below the fire give a dry bulb temperature of 99 °F and a relative humidity of 12 percent. The slope is 42 percent. What is the fine dead fuel moisture (FDFM)? Input the data values on the fine dead fuel moisture worksheet (see figure 8.1).

Fire Behavior Chapter 9

Overview The material in chapter 9 describes how to use Nomograms provide essential fire behavior information. To surface fire behavior and spotting nomograms, fire organize this information, input and output values are characteristic and interpretation charts, probability recorded on a fire behavior worksheet. Before beginning of ignition charts, and associated worksheets. work on the nomogram, the windspeed (usually obtained These charts, graphs, and worksheets easily from a local weather report) must be used to compute the capture known or calculated information to obtain midflame windspeed. See chapter 9, section 2. surface fire behavior characteristics, such as effective windspeed, heat per unit area, rate of Midflame windspeed and slope are needed to determine spread, and fireline intensity. Fire characteristics the effective windspeed in the lower left quadrant of the defined are flame length, spread distance, which is nomogram. Effective windspeed determines the turning converted to a map spread distance, flame height, point in the lower right quadrant of the nomogram. Dead maximum spotting distance, rate of spread, and fuel moisture, if not given, must be determined. See probability of ignition. chapter 8, section 2. Dead fuel moisture determines the turning point in the upper left quadrant and is the beginning of the final information line in the upper right quadrant. For live fuel moistures, a horizontal line is drawn 9.1 Surface Fire Behavior Nomograms Surface fire across both upper quadrants connecting these two points. behavior can be determined by using a series of charts Rate of spread, flame length, fireline intensity, and heat and graphs called nomograms. Variables of surface fire per unit area are read from the intersection of the final behavior include the effective windspeed, heat per unit information line and appropriate quadrant borders. area, rate of spread, and fireline intensity. A surface fire behavior nomogram is a set of four interconnected graphs Begin the nomogram by establishing all the inputs around that, when given a set of inputs, provides fire behavior the nomogram, then draw the information line around the characteristics as output values. nomogram, using the inputs as turning points, and conclude by reading the outputs. The following steps are a There are 26 surface fire behavior nomograms, consisting guide on how to read a nomogram. It is important that the of nomograms for each of the 13 fuel models, at both low correct nomogram is chosen for the fuel model being and high windspeeds. The range of values for low and studied. The input and output data can be recorded in a high windspeed nomograms varies depending on the fuel fire behavior worksheet. type. Consequently, windspeed and fuel type will determine the correct nomogram to be used. Surface Fire Behavior Nomogram Input Values Nomograms consist of four graphs, positioned in four quadrants. The upper left quadrant contains dead fuel 1. Fuel model—Select one of the 13 fire behavior fuel moisture in percentages and the live fuel (foliage) models discussed in chapter 8. moisture in percentages. The upper right quadrant contains the flame length, rate of spread, fireline intensity, 2. Live and dead fuel moistures—Fuel moisture content is heat per unit area, live fuel moisture in percentages, and the water content of a fuel expressed as a percentage of the dead fuel moisture in percentages. The lower left the oven dry weight of the fuel. Both dead and live fuel quadrant contains the midflame windspeed, percent moisture contents are used as inputs to the nomogram. slope, and the effective value of windspeed. The lower right quadrant contains the effective value of windspeed in 3. Midflame windspeed—Midflame windspeed is the miles per hour. windspeed within a wildland environment at about eye level, measured in miles per hour. See chapter 9, section 2.

99 Fire Behavior Chapter 9

4. Slope percent—Slope percent describes the steepness windspeed by the appropriate wind adjustment factor from of the site. For wildland fire behavior calculations, slope is figure 9.2. It is very important to know which fuel model always expressed as a percentage rather than by degree. and sheltering configuration is being studied, and whether It is found on the lower left quadrant of the nomogram. a given windspeed is a 20-ft windspeed or an already adjusted midflame windspeed. All of this information can 5. Effective windspeed—Effective windspeed combines be entered in a wind adjustment worksheet. See figure 9.1. the midflame windspeed and slope values into one input. It is found by using the nomogram, but is listed as an input Example 1—A fire is burning in a fully sheltered area of because once it is determined, it is used as a turning point dense, or closed, stands described as Fuel Model 4. The in the lower right quadrant. local weather station reports the 20-ft windspeed is 15 miles per hour. What is the midflame windspeed? Show all Surface Fire Behavior Nomogram Output Values work on the wind adjustment worksheet, figure 9.1.

1. Rate of spread—Rate of spread is the relative activity of Solution—Figure 9.2 describes wind reduction factors and a fire, expressed as a rate of advance of the head of the is used to determine the appropriate correction factor. fire in chains per hour (ch/h). Step 1. See figure 9.2. The correction factor is 0.1 for any 2. Heat per unit area—Heat per unit area is the total fuel model under fully sheltered conditions with dense amount of heat released per square foot during the stands. passage of the fire front. It is expressed in British thermal units per square foot (Btu/ft2). Step 2. To find the midflame windspeed, multiply the 20-foot windspeed by the adjustment factor. 3. Fireline intensity—Fireline intensity is the amount of heat released per linear foot of fire front per second. It is midflame windspeed = based on both rate of spread and heat per unit area of a 20-foot windspeed x adjustment factor fire and is expressed in British thermal units per foot per second (Btu/ft/s). MFWS = 15 mi/h x 0.1 = 1.5 mi/h

4. Flame length—Flame length is the distance between the flame tip and the midpoint of the flame depth at the Example 2—A 20-foot windspeed at the top of the ridge is base of the flame (in feet). Flame length is directly related reported to be 35 miles per hour, with fuel model 11 to fireline intensity. vegetation. What is the midflame windspeed? Show all work on the wind adjustment worksheet, figure 9.1.

9.2 Midflame Windspeed (MFWS) Midflame Step 1. See figure 9.4. The top of a ridge is indicated to be windspeed is defined as the velocity of the winds, in miles unsheltered. per hour, taken at the mid-height of the flames. MFWS will directly affect the direction of movement of the flaming Step 2. From figure 9.2, the adjustment factor is 0.4. front. This is important in fire spread calculations. Step 3. MFWS = 35 x 0.4 = 14 mi/h The midflame windspeed is determined by use of the wind adjustment table, which is in terms of fuel overstory exposure and fuel model. See figures 9.2 and 9.4. Windspeed that is measured 20 feet above any fuel or obstruction is referred to as a 20-foot windspeed. It is usually measured by a weather station. The midflame windspeed is obtained by multiplying the 20-foot

100 Fire Behavior Chapter 9

Wind Adjustment Worksheet

Input 0 PP Projection point ______Example 1 ______Example2 1 20’ W 20-ft windspeed, mi/h ______15 ______35 2 Model # Fuel model number (1-13) ______411 ______3 Shltr Wind sheltering ______41 ______1 = Unsheltered 2 = Partially sheltered 3 = Fully sheltered, open 4 = Fully sheltered, closed 4 WAF Wind adjustment factor ______0.1 ______0.4 (see figure 9.2) Output 1 MFWS Midflame windspeed, mi/h ______1.5 ______14 (line 1 x line 4)

Figure 9.1—Wind adjustment worksheet.

Fuel Exposure Fuel Model Adjustment Factor

Unsheltered Fuels 4 0.6 Fuel exposed directly to the wind. No or sparse overstory. Fuel 13 0.5 beneath timber that has lost its foliage; fuel beneath timber near 1, 3, 5, 6, 0.4 clearings or clearcuts; fuel on high ridges where trees offer 11, 12 0.4 little shelter from the wind. (2, 7)1 0.4 (8, 9, 10)2 0.4

Partially Sheltered Fuels All fuel 0.3 Fuel beneath patchy timber, where it is not well sheltered; fuel models beneath standing timber at midslope or higher on a mountain with wind blowing directly at the slope.

Fully Sheltered Fuels All fuel Open stands Fuel sheltered beneath standing timber on flat or gentle models 0.2 slope or near base of a mountain with steep slopes. Dense stands 0.1 1 Fuels usually partially sheltered 2 Fuels usually fully sheltered

Figure 9.2—Wind reduction factors.

101 Fire Behavior Chapter 9

Figure 9.3—Midflame winds vs 20-foot winds.

Figure 9.4—Fuel diagram.

102 Fire Behavior Chapter 9

Figure 9.5—Nomogram – fuel model 9. 103 Fire Behavior Chapter 9

DD D

U/S U/S U/S

B/L/A B/L/A B/L/A

F ______

Wind Adjustment Wind Worksheet

1,000 ft of site location

A = 1,000 ft to 2,000 ft above site A (table 2)

(table 3, 4, or 5) B = 1,000 ft to 2,000 ft below site L =

(line 6 + line 13)

(table 12)

1 = unsheltered 2 = partially sheltered 3 = fully sheltered, open 4 = fully sheltered, closed

(table 7)

(line 1 x line 4)

Fine Dead Fuel Moisture/Probability of Ignition Worksheet

0 PP Projection point ______1 D Daytime calculation ______2 DB Dry bulb temperature, 3 WB bulb temperature, Wet 4 DP Dew point, 5 RH % Relative humidity, ______6 RFM Reference fuel moisture, % ______

7 MO Month ______8 SH Unshaded (U) or shaded (S) ______9 T Time ______

1 1H-FDFM Fine dead fuel moisture, % ______

2 PIG Probability of ignition, % ______

11 ASP Aspect, (N, S, E, W) ______

12 SLP Slope, % ______13 FMC Fuel moisture correction, % ______10 CH Elevation change ______

Input

Output

Input 0 PP Projection point ______1W 20’ 20-ft windspeed, mi/h ______2# MODEL Fuel model number (1-13) ______3 SHLTR Wind sheltering ______

4 WAF Wind adjustment factor ______

Output

1 MFWS Midflame windspeed, mi/h ______

______

Slope Worksheet

Fire Behavior Worksheet

Map spread distance, in ______

Map distance spot, in ______

(between points)

Name of fire______Fire pred spec ______Date______Time ______Proj period date ______Proj time from ______to ______

Input 0 PP Projection point ______1 Model # Fuel model number (1-13) ______2 1H-FDFM Fine dead fuel moisture, % ______3 LFM Live fuel moisture, % ______4 MFWS Midflame windspeed, mi/h ______5 SLP slope, % ______6 EWS windspeed, mi/h Effective ______

Output 1 ROS Rate of spread, ch/h ______2 HA Heat per unit area, Btu/ft

3 FLI Btu/ft/s Fireline intensity, ______4 FL Flame length, ft ______5 SD Spread distance, ch ______

6 PER ch Perimeter, ______7 AC Area, ac ______8 SPOT Max spotting distance, mi ______

9 PIG Probability of ignition, % ______

Input 0 PP Projection point ______1 CON INT Contour interval, ft ______2 SLC Map scale ______3 CF ft/in Conversion factor, ______4 # INTVLS Number of contour intervals ______5 RISE Rise in elevation ______6 MD Map distance, in ______

7 HZGD Horizontal ground distance, ft ______

Output 1 SLP% Slope, % ______

Nomogram version Ð June 1993

Figure 9.6—Nomogram worksheet. 104 Fire Behavior Chapter 9

Example 3—A fire is spreading uphill in hardwood litter, Step 2. Using the lower right quadrant of the nomogram, fuel model 9, on a 55 percent slope. The midflame see figure 9.8: windspeed is 5 miles per hour. The wind is blowing uphill. a. Locate the line along the right side, which represents The fine dead fuel moisture is 3 percent. Determine the the effective windspeed determined in step 1c, (in rate of spread, flame length, fireline intensity, and heat per most cases a line will need to be drawn approximating unit area. the effective windspeed value, if it does not appear along the outside edge of the lower right quadrant). The following nomograms and worksheet were used to This line will be the turning point in the continuous solve example 3. information line drawn around the nomogram. Figure 9.5—Nomogram—fuel model 9 Figure 9.6—Nomogram worksheet b. The line must always be located to the right of the dashed line. See the note on the graph. If the vertical Solution line from the chart above intersects the effective Step 1. Determine nomogram input values. windspeed line to the left of the dashed line, the rate of a. Determine effective windspeed. In the lower left spread and flame length may be overestimated. When quadrant find the percent slope and draw a vertical line the vertical line is to the left of the dashed line, recheck up. See figure 9.7. the windspeed. This is typical when the low windspeed graph is being used, when the high windspeed b. Find the midflame windspeed on the right-hand side nomogram may be more appropriate. of the same quadrant. Follow the curved line down to the left until it intersects the line just made. If the midflame windspeed lies between the index values, make an approximation of the intersection.

c. From this intersection, draw a horizontal line to the left side of the lower left quadrant and read the effective windspeed (6 mi/h). Record the effective windspeed on the worksheet.

Figure 9.8—Nomogram—lower right quadrant.

Figure 9.7—Nomogram–lower left quadrant. 105 Fire Behavior Chapter 9

Step 3. Using the upper left quadrant of the nomogram, see figure 9.9. a. Fuel models with dead fuels require finding or approximating a line in the upper left quadrant for the dead fuel moisture. If an approximation is made, start drawing the line in the bottom right corner and estimate where the moisture value lies in relation to the index values along the edge.

b. This fuel moisture line in the upper left quadrant will serve as another turning point for the continuous line to be drawn.

Figure 9.10—Nomogram–upper right quadrant.

c. At this intersection, turn a right angle and draw a horizontal line across to the diagonal line in the lower left quadrant.

d. At this intersection, turn a right angle and draw a vertical line up into the upper left quadrant to the diagonal line for dead fuel moisture identified in step 3.

Figure 9.9—Nomogram—upper left quadrant. e. At this intersection, turn a right angle and draw a horizontal line across to the vertical line in the upper right quadrant that was drawn in step 4b. Step 4. The nomogram is now set up to begin the continuous information line through the four quadrants, f. At this intersection, draw a small circle. using the established values as turning points. a. Starting in the upper right quadrant, draw a Step 5. Read the fire behavior output values off the horizontal line from the dead fuel moisture percent nomogram at the intersections of the completed value intersecting the S-shaped curve in the quadrant, information line and the appropriate borders, and record see figure 9.10. the values on the fire behavior worksheet. a. Rate of spread is read at the left margin of the upper b. At this intersection, turn a right angle and draw a right quadrant, where the horizontal line from step 4e vertical line down to the lower right quadrant, stopping enters the quadrant (16 ch/h). Record the rate of at the effective windspeed line identified in step 2a. spread on the fire behavior worksheet. If the vertical line intersects the wind limit dashed line in the lower right quadrant before intersecting the effective b. Heat per unit area is read along the bottom margin of windspeed line, stop and begin the nomogram again, the upper right quadrant at the intersection of the line using the high windspeed nomogram. 106 Fire Behavior Chapter 9

constructed in step 4b (450 Btu/ft2). Record the heat c. From this intersection, draw a horizontal line to the per unit area on the worksheet. left side of the lower left quadrant and read the effective windspeed (6 mi/h). Record the effective c. Flame length is read by finding the small circle in the windspeed on the worksheet. upper right quadrant that was drawn in step 4f. Follow the curved ray that lies nearest the circle to the top of Step 2. Using the lower right quadrant of the nomogram. the quadrant. Flame lengths are read to the nearest See figure 9.14. whole foot at the top of the quadrant (4 feet). Record a. Locate the line along the right side, which the flame length on the fire behavior worksheet. represents the effective windspeed determined in Step 1c (typically a line needs to be drawn approximating d. Fireline intensity is read from the numbers the effective windspeed value, if it does not appear embedded in the curved lines in the upper right along the outside edge of the lower right quadrant). quadrant. Find the small circle that was drawn in step 4f This line will be the turning point in the continuous line and estimate the fireline intensity by the location to the drawn around the nomogram. nearest curved ray (120 Btu/ft/s). Record the fireline intensity in the worksheet. Step 3. Prepare upper quadrants and draw a horizontal line for live and dead fuels. See figure 9.16. See figure 9.11 for a completed nomogram and figure a. Locate the fine dead fuel moisture values on the 9.12 for a completed worksheet. outer axis of both upper quadrants. Draw a horizontal line across both quadrants, connecting the fine dead fuel moistures. 9.3 Fire Behavior Calculations for Fuel Models Using Live and Fine Dead Fuel Moisture Values b. Find where this line intersects the correct live fuel moisture curve in the upper left quadrant, and draw a Example 4— A fire is spreading uphill in brush, fuel model straight line to the lower right corner of that same 5, with enough green fuel in the understory to affect fire quadrant. This line is referred to as the “K” line. behavior. The midflame windspeed is 5 miles per hour, slope is 30 percent, and the fine dead fuel moisture is 4 c. If the horizontal line does not cross the correct live percent. The fuel moisture content needs to be estimated fuel moisture curve, extend the curve in approximately due to a live fuel component. See figure 8.2. The foliage is the same arc until it intersects the fine dead fuel line almost mature and comparable to older foliage, so 150 and draw the “K” line from this point. percent moisture content can be estimated. Step 4. The nomogram is now set up and ready to begin The following nomogram and worksheet were used to the continuous line through the 4 quadrants. solve the problem. a. In the upper right quadrant, locate the point where Figure 9.15—Nomogram–fuel model 5 the dead fuel moisture line drawn in step 3a intersects Figure 9.18—Completed worksheet the appropriate live fuel moisture curve.

Step 1. Determine the effective windspeed. b. From this point, draw a vertical line down into the a. In the lower left quadrant, find the percent slope and lower right quadrant to intersect the correct effective draw a vertical line up. See figure 9.13. windspeed line. Remember to stop and go to a high windspeed nomogram if the dashed wind limit line is b. Find the midflame windspeed on the right-hand side intersected. of the same quadrant. Follow the curved line down to the left until it intersects the line made in step 1a. If the c. At this intersection, turn a right angle and draw a midflame windspeed lies between the index values, horizontal line across to the diagonal line in the lower make an approximation of the intersection. left quadrant.

107 Fire Behavior Chapter 9

Figure 9.11—Completed nomogram. 108 Fire Behavior Chapter 9

DD D

U/S U/S U/S

B/L/A B/L/A B/L/A

F ______

Wind Adjustment Wind Worksheet

1,000 ft of site location

A = 1,000 ft to 2,000 ft above site A (table 2)

(table 3, 4, or 5) B = 1,000 ft to 2,000 ft below site L =

(line 6 + line 13)

(table 12)

1 = unsheltered 2 = partially sheltered 3 = fully sheltered, open 4 = fully sheltered, closed

(table 7)

(line 1 x line 4)

Fine Dead Fuel Moisture/Probability of Ignition Worksheet

Input

0 PP Projection point ______1 D Daytime calculation ______2 DB Dry bulb temperature, 3 WB bulb temperature, Wet 4 DP Dew point, 5 RH % Relative humidity, ______6 RFM Reference fuel moisture, % ______

7 MO Month ______8 SH Unshaded (U) or shaded (S) ______9 T Time ______

1 1H-FDFM Fine dead fuel moisture, % ______

2 PIG Probability of ignition, % ______

11 ASP Aspect, (N, S, E, W) ______

12 SLP Slope, % ______13 FMC Fuel moisture correction, % ______10 CH Elevation change ______

Output

Input 0 PP Projection point ______1W 20’ 20-ft windspeed, mi/h ______2# MODEL Fuel model number (1-13) ______3 SHLTR Wind sheltering ______

4 WAF Wind adjustment factor ______

Output

1 MFWS Midflame windspeed, mi/h ______

9 3

N/A

450 120

______

Slope Worksheet

Fire Behavior Worksheet

Map spread distance, in ______

Map distance spot, in ______

(between points)

Name of fire______Fire pred spec ______Date______Time ______Proj period date ______Proj time from ______to ______

Output 1 ROS Rate of spread, ch/h ______2 HA Heat per unit area, Btu/ft

3 FLI Btu/ft/s Fireline intensity, ______4 FL Flame length, ft ______5 SD Spread distance, ch ______

6 PER ch Perimeter, ______7 AC Area, ac ______8 SPOT Max spotting distance, mi ______

9 PIG Probability of ignition, % ______

7 HZGD Horizontal ground distance, ft ______

Output 1 SLP% Slope, % ______

Nomogram version Ð June 1993

Figure 9.12—Partially completed worksheet. 109 Fire Behavior Chapter 9

Figure 9.13—Nomogram–lower left quadrant. Figure 9.14—Nomogram–lower right quadrant.

110 Fire Behavior Chapter 9

Figure 9.15—Nomogram–fuel model 5. 111 Fire Behavior Chapter 9

Figure 9.16—Nomogram–upper left and upper right quadrants.

d. At this intersection in the lower left quadrant, draw a step 4f. Follow that line to the top of the page and vertical line up into the upper left quadrant, intersecting estimate the flame length to the nearest foot (3 feet). the “K” line. Record the flame length on the fire behavior worksheet. e. At this intersection, draw a horizontal line to the vertical line drawn in step 4b. c. Fireline intensity is read from this same point. Estimate the closest curve to that point and read the f. At this intersection, draw a small circle. associated intensity value for that line (60 Btu/ft/s). Record the fireline intensity on the worksheet. Step 5. Read the outputs from the completed nomogram. Record the values on the fire behavior worksheet. d. Heat per unit area is read at the lower margin of the a. Rate of spread is read from the left margin of the upper right quadrant, where the line constructed in upper right quadrant at the point intersected by the line step 4b intersects the border (300 Btu/ft2). Record the drawn in step 4e (11 ch/h). Be careful not to read the heat per unit area on the worksheet. rate of spread off the dead fuel moisture line. Record the rate of spread on the fire behavior worksheet. See figure 9.17 for a completed nomogram and figure 9.18 for a completed worksheet. b. Flame length is read by locating the curved line in the upper right quadrant nearest the point circled in

112 Fire Behavior Chapter 9

Figure 9.17—Completed nomogram. 113 Fire Behavior Chapter 9

DD D

U/S U/S U/S

B/L/A B/L/A B/L/A

F ______

Wind Adjustment Wind Worksheet

1,000 ft of site location

A = 1,000 ft to 2,000 ft above site A (table 2)

(table 3, 4, or 5) B = 1,000 ft to 2,000 ft below site L =

(line 6 + line 13)

(table 12)

1 = unsheltered 2 = partially sheltered 3 = fully sheltered, open 4 = fully sheltered, closed

(table 7)

(line 1 x line 4)

Fine Dead Fuel Moisture/Probability of Ignition Worksheet

0 PP Projection point ______1 D Daytime calculation ______2 DB Dry bulb temperature, 3 WB bulb temperature, Wet 4 DP Dew point, 5 RH % Relative humidity, ______6 RFM Reference fuel moisture, % ______

7 MO Month ______8 SH Unshaded (U) or shaded (S) ______9 T Time ______

1 1H-FDFM Fine dead fuel moisture, % ______

2 PIG Probability of ignition, % ______

11 ASP Aspect, (N, S, E, W) ______

12 SLP Slope, % ______13 FMC Fuel moisture correction, % ______10 CH Elevation change ______

Input

Output

Input 0 PP Projection point ______1W 20’ 20-ft windspeed, mi/h ______2# MODEL Fuel model number (1-13) ______3 SHLTR Wind sheltering ______

4 WAF Wind adjustment factor ______

Output

1 MFWS Midflame windspeed, mi/h ______

5 4

150

300

______

Slope Worksheet

Fire Behavior Worksheet

Map spread distance, in ______

Map distance spot, in ______

(between points)

Name of fire______Fire pred spec ______Date______Time ______Proj period date ______Proj time from ______to ______

Output 1 ROS Rate of spread, ch/h ______2 HA Heat per unit area, Btu/ft

3 FLI Btu/ft/s Fireline intensity, ______4 FL Flame length, ft ______5 SD Spread distance, ch ______

6 PER ch Perimeter, ______7 AC Area, ac ______8 SPOT Max spotting distance, mi ______

9 PIG Probability of ignition, % ______

7 HZGD Horizontal ground distance, ft ______

Output 1 SLP% Slope, % ______

Nomogram version Ð June 1993

Figure 9.18—Completed worksheet. 114 Fire Behavior Chapter 9

9.4 Using the Fire Behavior Nomogram Backwards What are the flame lengths? for Prescribed Burns Prescribed fire is the controlled application of fire to Note that the rate of spread is given, rather than a flame wildland fuels, in either their natural or modified state, length. under specified environmental conditions. These conditions allow the fire to be confined to a predetermined a. The 16 chain per hour rate of spread is located. area. At the same time, these fires produce the intensity of heat, flame length, and rate of spread required to attain b. A horizontal line is drawn across the upper right planned resource management objectives. Using quadrant. The intersection at the right axis indicates nomograms backwards develops a range of effective the fine dead fuel moisture. See figure 9.19. windspeeds and fine fuel moistures, which will yield the desired resource management objectives. c. The fine dead fuel moisture is circled in both the upper right and upper left quadrants. For this example, Step 1. Using nomograms in reverse. 18 percent is circled. a. Locate the desired point on the flame length curve. Draw a line from this point, intersecting the S-curve e. A horizontal line is drawn from the intersection of the and continuing down through all windspeed lines in the S-curve in the upper right quadrant to the line of 18 lower right quadrant. percent fine dead fuel moisture in the upper left quadrant. b. Draw a horizontal line from the S-curve intersection in the upper right quadrant to determine the fine fuel f. A vertical line is drawn from the intersection with the moisture. Circle this fuel moisture value in the upper S-curve in the upper right quadrant, down through all right and upper left quadrants. the effective windspeeds in the lower right quadrant.

c. In the upper right quadrant, draw a horizontal line g. A vertical line is drawn into the lower left quadrant into the left quadrant from the point intersecting the fine from the fuel moisture intersection in the upper left fuel moisture line. quadrant, until the diagonal is reached. At this point, a horizontal line is drawn into the lower right quadrant. d. Draw a vertical line down into the lower left quadrant, turning at the diagonal, and continuing with a h. The intersection point with the vertical line is located horizontal line into the lower right quadrant. in the lower right quadrant. The effective windspeed is determined as 5 miles per hour (approximation). e. Locate the intersecting point of the line in part d with the vertical line drawn in part a, and determine the i. The flame length can be approximated from the effective windspeed. upper right quadrant as 4 feet.

Example 5—Prepare a prescription for a firing operation for tomorrow’s shift. Handcrews are constructing indirect handline in advance of the fire. The concern is that the fire will burn through the area before the crews can complete this line. Determine a range of dead fuel moistures and effective windspeeds that will keep the fire’s forward spread within a rate of 16 chains per hour, using fuel model 6.

What is the range of dead fuel moistures and effective windspeeds needed to safely complete the handline?

115 Fire Behavior Chapter 9

Figure 9.19—Completed nomogram.

116 Fire Behavior Chapter 9

9.5 Flame Length The flame length is the distance 9.7 Head, Flank, and Rear Fire Terms Each side of between the flame tip and the midpoint of the flame depth the fire is described in terms of head, flank, and rear. The at the base of the flame. Flame length is an observable, head is the fastest spreading part of a fire’s perimeter. measurable indicator of fireline intensity. Spread distance, This is usually the side toward which the wind is blowing in chains, is the distance of forward fire spread for a (leeward) or the upslope side. The head of the fire is of specified amount of time. primary interest. The right and left flanks describe the sides of the fire. Flanks are perpendicular to the head of spread distance (SD) = the fire. The rear of the fire is the side of the fire opposite rate of spread (ROS) x projection time (PT) the head. SD = ROS x PT Example 8—Plot the perimeter and label the head, rear, Example 6—The rate of a fire spread is 4 chains per hour. and flanks of the fire in example 7. Assume the wind is What will the spread distance be in 3 hours? blowing from left to right across the page. ➤➤➤➤➤➤

SD = ROS x PT = 4 ch/h x 3h = 12 ch Left flank

Rear Head

9.6 Map Spread Map spread, in inches, is the size of Right flank a fire as scaled to a map.

Example 7—Using example 6, find the map distance for 9.8 Flame Height Flame height is the average height the fire spread. Plot the distance using a tenths ruler for of flames, as measured on a vertical axis. accuracy. The map scale is 1:24,000. Example 9—The torching tree diameter at breast height Step 1. Convert the map scale to feet per inch. (dbh) is 25 inches in a forest of ponderosa pine. What is 24,000 inches 1 foot = 2,000 feet the flame height? 12 inches Step 1. Use spotting nomogram 1, figure 9.21. Find 25 Step 2. Convert the spread distance to feet. inches diameter at breast height on the horizontal axis. 12 chains 66 feet = 792 feet 1 chain Step 2. Go up to the ponderosa pine line.

Step 3. Convert the ground spread distance to a map Step 3. Move to the left to find the flame height on the spread distance. vertical axis. 792 feet 1 inch = 0.396 inch = 0.4 inch 2,000 feet The flame height is 57 feet.

Step 4. Using a ruler, measure the distance from the point of origin to the distance of the fire spread. 9.9 Maximum Spotting Distance Maximum spotting distance, in miles, is the maximum transported distance of Map spread distance is 0.4 inch. a firebrand. It can be predicted for various firebrand sources using such factors as the probability of production of firebrands, windspeed, fire intensity, and the number of firebrands. The maximum spotting distance will be determined by using spotting nomograms. The maximum spotting distance can also be determined by using a computer program called Behave or by the HP-71B.

117 Fire Behavior Chapter 9

Five input values are needed to find the maximum Step 9. On spotting nomogram 3, find the flame duration spotting distance. They are: of 4.2 on the horizontal axis. 1. Torching tree height, ft 2. Torching tree species Step 10. Since the ratio of tree height to flame height is 3. Torching tree diameter at breast height (dbh), in 1.3, move up to the “1.0 to the 1.5” line. 4. Average tree cover height, ft 5. Windspeed at 20-ft height, mi/h. Step 11. Move to the left to find the ratio of lofted firebrand height to flame height on the vertical axis (6.8). Calculations are completed in stages, using spotting Record on line 2C of the worksheet. nomograms 1 through 4. Step 12. Find the height above the tree to which a Example 10a—Find the maximum spotting distance. firebrand will be lofted by multiplying the flame height by dbh = 30 in the ratio of lofted firebrand height to flame height. Torching tree species = douglas fir 75 ft x 6.8 = 510 ft Torching tree height = 100 ft Record on line 2E. Average tree cover height = 90 ft Windspeed at 20-ft height = 20 mi/h Step 13. Divide the torching tree height by 2. 100 ft/2 = 50 ft The following nomograms and worksheet were used to Record on line 1D of the worksheet. solve example 10a. Figure 9.20—Spotting worksheet Step 14. Add this value to the lofted firebrand height. Figure 9.21—Spotting nomogram 1 50 ft + 510 ft = 560 ft Figure 9.22—Spotting nomogram 2 This is the expected height above the ground that a Figure 9.23—Spotting nomogram 3 firebrand will be lofted. Record on line 4 of the worksheet. Figure 9.24—Spotting nomogram 4 Step 15. If the forest is open, divide average tree cover Step 1. Enter the given values into the spotting worksheet. height by 2 and enter effective height. If not, enter the average of the cover height. For this example, assume Step 2. Use spotting nomogram 1. Find 30 inches that the forest has a closed canopy. diameter at breast height on the horizontal axis. Enter 90 for effective tree cover height.

Step 3. Go up to the douglas fir line. Step 16. Multiply the windspeed of 20 miles per hour by 2/3. 20 x 2/3 = 13 Step 4. Go to the left to find flame height (75 feet) on the Record this value on line 5F on the worksheet. vertical axis. Record the value on line 2B of the spotting worksheet. Step 17. On spotting nomogram 4, find the firebrand height of 560 feet on the right portion of the horizontal Step 5. On spotting nomogram 2 find the 30 inch axis—interpolate (insert) between 500 and 600. diameter at breast height on the horizontal axis. Step 18. Go up to the effective tree cover height of 90 Step 6. Go up to the douglas fir line. feet. Interpolate between 50 and 100.

Step 7. Go to the left to find flame duration on the vertical axis Step 19. Go to the left to the treetop windspeed of 13 miles (4.2). Record the value on line 3 of the spotting worksheet. per hour. Interpolate between 10 and 15.

Step 8. Find the ratio of tree height to flame height by Step 20. Go down and read the maximum spotting dividing the value of the tree height by the value of the distance on the left portion of the horizontal axis, flame height. (0.35mi le). 100 ft/75 ft = 1.33 Record this value under output on the worksheet. Record on line 2 of the worksheet. 118 Fire Behavior Chapter 9

INPUT 1. Torching (A) (A) (D) tree 100 2 = 50 50 height

2. Torching (B) (A) (C) (E) Doug. NOM.1 NOM.3 tree Fir 75 (B) 1.33 6.8 510 species Flame Ratio of tree Ratio of lofted (B) X (C) = (E) height (ft) height to flame firebrand height 3. Torching NOM.2 height to flame height tree 30 4.2 DBH (in) Flame (D) + (E) = duration 560 4. Average If forest is Maximum tree cover 90 open, divide by 2, 90 firebrand otherwise retain height height (ft) full height Effective tree NOM.4 cover height (ft) OUTPUT 5. Windspeed (F) at 20-ft 20 (F) x 2/3 = 13 .35 height (mi/h) Treetop Maximum windspeed (mi/h) spotting distance (mi)

Figure 9.20—Spotting worksheet.

Figure 9.21—Spotting nomogram 1. 119 Fire Behavior Chapter 9

Figure 9.22—Spotting nomogram 2. 120 Fire Behavior Chapter 9

Figure 9.23—Spotting nomogram 3.

121 Fire Behavior Chapter 9

Figure 9.24—Spotting nomogram 4. 122 Fire Behavior Chapter 9

Example 10b—Based on the information from example 9.11 Fire Characteristic and Interpretation Charts 9a, fill out the map-spot worksheet, figure 9.25. Use a map Several charts are available for determining rate of scale of 1:24,000 to obtain the conversion factor on line 4, inch spread, flame length, and heat per unit area. The fire per inch map scale must be converted to feet per inch. Set up characteristics charts for both light and heavy fuels are a a cancellation table so all units cancel, except feet per inch. graphic method of indicating ROS, FL, and heat per unit area, in British thermal units per square foot. See figures 24,000 in 1 ft = 2,000 ft/in 9.26 and 9.27. A table of fire suppression interpretations in 12 in provides guidelines for the fire characteristics charts. See figure 9.28. .35 mi 5,280 ft = 1,848 ft mi The fire characteristics charts are used to determine the best mode of attack for a fire. The main criterion used is 1,848 ft in = .9 in flame length. For each category and range of flame 2,000 ft length, a sketch on the chart indicates the best mode of attack.

Line Input Example 11—A fire burning in light fuel has a ROS of 20 spot 0 PP Projection point ______chains per hour and a heat per unit area of 800 British 0.35 1 SPOTMI Spotting distance, mi ______thermal units per square foot. What is the flame length? 1,848 2 SPOTFT Spotting distance, ft ______Use the fire characteristics chart, figure 9.26, to solve (line 1 x 5,280 ft) example 10. 3 SCL Map scale 1:24,000______2,000 4 CF Conversion factor, ft/in ______Step 1. Go to 800 British thermal units per square foot on Output the horizontal axis of the fire characteristics chart. Draw a 0.9 1 SPOT Map distance spot, in ______vertical line up from this point. (line 2 divided by line 4) Step 2. At the point of 20 chains per hour on the vertical Figure 9.25—Map-spot worksheet. axis, draw a horizontal line to the right. Intersect the horizontal and vertical lines.

9.10 Rate of Spread (ROS) The rate of spread is in Step 3. Follow this point to the right to find the flame chains per hour (ch/h) and is defined as the speed with length, interpolate between 8 feet and 4 feet, which is 6 which the fire is moving away from the site of origin. Wind, feet. moisture, and slope drive the fire. The flaming zone, or fire head, moves away from the origin quickly with great The flame length is 6 feet. intensity. When the combined effects of wind and slope increase the ROS, the flame length is increased.

123 Fire Behavior Chapter 9

Figure 9.26—Fire characteristics chart, light fuels. 124 Fire Behavior Chapter 9

Figure 9.27—Fire characteristics chart, heavy fuels. 125 Fire Behavior Chapter 9

Flame Fireline Example 13—A fire burning in heavy fuel has a flame Length Intensity length of 8 feet and a ROS of 20 chains per hour. What is (ft) (Btu/ft/s) Interpretations the heat per unit area? Use figure 9.27. 0-4 0-100 Fires can generally be attacked at the head or flanks by persons using handtools. Step 1. Go to 20 chains per hour on the vertical axis.

4-8 100-500 Handline should hold the fire. Fires are Step 2. Go to the right until the 8 foot flame length line is too intense for direct attack on the head reached. by persons using handtools.

Handline cannot be relied on to hold fire. Step 3. Go down at this point and read the value on the Equipment such as dozers, engines, and horizontal axis as 1,300 British thermal units per square retardant aircraft can be effective. foot.

8-11 500-1,000 Fires may present serious control 2 problems—torching out, crowning, and The heat per unit area is 1,300 Btu/ft . spotting.

Control efforts at the head of the fire will 9.12 Slope Effect on ROS When fire moves upslope, probably be ineffective. the fuel ahead of the flame front is closer to the flame than 11+ 1,000+ Crowning, spotting, and major runs if the slope were flatter. This is called preheating of fuels. are common. The effects of slope become greater as the slope increases. The first tripling of slope roughly increases Control efforts at the head of the fire are ineffective. the rate of spread by 2. The second tripling of slope increases the rate of spread by factors of 4 to 6. CAUTION: These are not guides to personal safety. Fires can be dangerous at any level of intensity. Wilson (1977) has Example 14—An area of shrubs is burning at a ROS of 4 shown that most fatalities occur in light fuels on small fires or chains per hour at an 8 percent slope. The slope isolated sections of large fires. increases to 24 percent. What will the ROS be? The slope Figure 9.28—Fire suppression interpretations. went from 8 to 24 percent. This is an increase of three times the original slope. As stated above, the rate of Example 12—In example 11, assume that the fuel spread will then double. characteristics remain the same and the ROS increases to 40 chains per hour as a result of the slope and wind. 4 ch/h x 2 = 8 ch/h What is the resulting flame length?

Step 1. The heat per unit area is the same. Go to 40 chains per hour on the vertical axis. 9.13 Probability and Number of Ignitions Probability is the chance that an event will happen and is in terms of Step 2. Draw a horizontal line to the right from this point percent, or per 100. For example, if there is a 40 percent until it intersects the vertical line. chance of a spot fire starting, that means that out of 100 glowing embers that fly off, 40 embers will start spot fires, Step 3. Follow this point to the right to find the flame length, 60 will not. Percent is calculated by changing the percent interpolate between 8 feet and 11 feet, which is 9 feet. into a fraction by dividing by 100, then multiplying by the total number of possible situations. The flame length is 9 feet. Example 15—The probability of ignition is 80 percent. The fire characteristics chart can be used to find the heat How many ignitions will occur if 90 glowing firebrands land per unit area if the ROS and flame length are known. on receptive fuel?

126 Fire Behavior Chapter 9

Step 1. Change 80 percent to a fraction, 80 = 0.8 then into a decimal. 100

Step 2. Multiply by the total number of situations, in this case glowing firebrands. 0.8 x 90 = 72

Expect 72 ignitions out of 90 glowing firebrands.

9.14 Probability of Ignition Probability of ignition is a rating of the probability that a glowing firebrand will cause a fire, providing it lands on receptive fuels and the fuels are dry enough to support ignition. Probability of ignition is determined by fuel shading, fine dead fuel moisture, and the dry bulb temperature. These inputs are determined when the fine dead fuel moistures are calculated. Probability of ignition can be determined by using the Probability of Ignition Table, figure 9.29. Fuel shading can be caused by clouds, canopy cover, or both. This table is divided into two portions, fuels that have either less than or more than 50 percent cloud or canopy cover.

Example 16—A fire is burning under a dense canopy of pole-sized trees. The dry bulb temperature is 84 °F. The fine dead fuel moisture is 5 percent. What is the probability of ignition?

Step 1. In the lower portion of the probability of ignition table, >50 percent, find the dry bulb temperature range that would include 84 °F. 80-89; draw a line across.

Step 2. Find the fine dead fuel moisture of 5 on the top horizontal row. Go down until the 80-89 line is intersected. Read 60 percent off the chart.

The probability of ignition is 60 percent.

127 Fire Behavior Chapter 9

Fine Dead Fuel Moisture (Percent) Dry Bulb Shading Temp. 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 (Percent) (°F)

110+ 100 100 80 70 60 60 50 40 40 30 30 20 20 20 20 10 100-109 100 90 80 70 60 60 50 40 40 30 30 20 20 20 10 10 90-99 100 90 80 70 60 50 40 40 30 30 30 20 20 20 10 10

80-89 100 90 80 70 60 50 40 40 30 30 20 20 20 10 10 10 Unshaded 70-79 100 80 70 60 60 50 40 40 30 30 20 20 20 10 10 10 <50% 60-69 90 80 70 60 50 50 40 30 30 20 20 20 20 10 10 10

50-59 90 80 70 60 50 40 40 30 30 20 20 20 10 10 10 10 40-49 90 80 70 60 50 40 40 30 30 20 20 20 10 10 10 10 30-39 80 70 60 50 50 40 30 30 20 20 20 10 10 10 10 10

110+ 100 90 80 70 60 50 50 40 40 30 30 20 20 20 10 10 100-109 100 90 80 70 60 50 50 40 30 30 30 20 20 20 10 10 90-99 100 90 80 70 60 50 40 40 30 30 20 20 20 10 10 10

80-89 100 80 70 60 60 50 40 40 30 30 20 20 20 10 10 10 Shaded 70-79 90 80 70 60 50 50 40 30 30 20 20 20 20 10 10 10 >50% 60-69 90 80 70 60 50 40 40 30 30 20 20 20 10 10 10 10

50-59 90 80 70 60 50 40 40 30 30 20 20 20 10 10 10 10 40-49 90 80 60 50 50 40 30 30 30 20 20 20 10 10 10 10 30-39 80 80 60 50 50 40 30 30 20 20 20 10 10 10 10 10

Figure 9.29—Probability of ignition.

128 Fire Behavior Chapter 9

The operations unit needs a range of dead fuel moistures EXERCISES and effective windspeeds that will keep the fire’s forward spread within 18 chains per hour. This will allow the Problem 1. What is the midflame windspeed in a partially handcrews to safely complete the indirect line. She sheltered area of fuel model 13 if the 20-foot windspeed is determines that the fire is burning in a fuel model 9. given as 16 miles per hour? What is the range of dead fuel moistures and effective windspeeds needed to safely complete the handline? Problem 2. A fire is burning in unsheltered fuel. Joy determines that the fuel is a model 4 fuel and is told that What is the flame length? the 20-foot winds are blowing at 11 miles per hour. What is the midflame windspeed? Use Nomogram Ð 9. Hardwood litter. See appendix E.

Problem 3. A fire is spreading up a 35 percent slope in Problem 6. The rate of spread of the fire is 6 chains per tall grass of fuel model 3. The midflame windspeed is 4 hour. What will the spread distance be in 4 hours? miles per hour and is blowing uphill. The fine dead fuel moisture in the grass is 4 percent. Determine the rate of spread, flame length, fireline intensity, and heat per unit Problem 7. What is the map distance of the ground area. Use the following nomograms and worksheet in spread distance from problem 6 on a map with a scale of appendix E to solve the problem. 1:62,500?

Nomogram—3. Tall grass (2.5 ft)—Low windspeed Nomogram worksheet Problem 8. There is a fire in a Grand Fir forest. The diameter at breast height is 33 inches. What is the flame height? Problem 4. A fire is spreading uphill in timber litter with enough green fuel in the understory to affect fire behavior. The timber is considered a fuel model 10. The midflame Problem 9. Input the following values into the spotting windspeed is 5 miles per hour, the fine dead fuel moisture worksheet. is 3 percent, and the slope is 20 percent. The live fuel Torching tree DBH = 15 in moisture can be approximated at 100 percent. Torching tree height = 120 ft Average tree cover height = 100 ft Determine the rate of spread, heat per unit area, flame Windspeed at 20-ft height = 30mi/h length, and fireline intensity for this fire. Use the following Torching tree species—lodgepole pine nomograms and worksheet found in appendix E to solve the problem. Problem 10. Using the data above, find the flame height Nomogram Ð10. Timber (Litter & Understory)—Low and flame duration. windspeed Nomogram worksheet

Problem 5. The operations unit has asked Peg to Problem 11. Using the data above, find the ratio of lofted prepare a “prescription” for an operational plan for firebrand height to flame height. tomorrow’s day shift. Handcrews are constructing indirect handline in advance of the fire. The concern is that the fire will burn through the area before the crews can Problem 12. For a closed canopy forest with the above complete the line. data, find the maximum spotting distance.

129 Fire Behavior Chapter 9

Problem 13. A fire has a ROS of 30 chains per hour and CHAPTER PROBLEM a heat per unit area of 900 British thermal units per square foot. What is the flame length? A fire is burning in the Los Padres National Forest in the middle of July. Readings are taken at a site 500 feet above the fire. The weather conditions are as follows: Problem 14. If the wind and slope increase the ROS to 20-foot windspeed of 15 mi/h 60 chains per hour, but the fuel characteristics remain the Fuel model 4 dbh = 15 in same, what will the resulting flame length be? Dry bulb temperature of 85 °F % slope is 40 percent Wet bulb temperature of 52 °F West aspect Live fuel moisture of 150 percent Problem 15. A fire is spreading at a rate of 40 chains per hour. The flame length is 8 feet. What is the heat per unit area? Find the fine dead fuel moisture, effective windspeed (EWS), flame length (FL), rate of spread (ROS), fireline intensity, and midflame windspeed (MFWS). Problem 16. In the fire in problem 15, the ROS increased to 70 chains per hour. The fuel characteristics are the Can crew B take direct attack of the fire at the head? same. What is the flame length? The fire is under 60 percent canopy and sky cover. What is the probability of ignition? Problem 17. There is a fire in a field of tall grass. The slope is 8 percent and the ROS is 5 chains per hour. If the The time is 1400 hours. What will the forward spread slope increases to 24 percent, what will the ROS be? If it distance be at 2100 hours? increases to 72 percent, what will the ROS be? Plot the forward spread distance on a map with a scale of 1:7,920. What is the probability of ignition? Problem 18. The probability of ignition is 60 percent. How many ignitions will there be if 75 glowing firebrands land on receptive fuel?

Problem 19. A fire is burning in brush under 30 percent sky cover. The dry bulb temperature is 94 °F. The fine dead fuel moisture is 4 percent. What is the probability of ignition?

130 Introduction to Wildland Fire Behavior S-190

Student Workbook NFES 2901 march, 2006

Introduction to Wildland Fire Behavior S-190

Student Workbook MARCH, 2006 NFES 2901

Sponsored for NWCG publication by the NWCG Training Working Team. The use of trade, firm, or corporation names in this publication is for the information and convenience of the reader and does not constitute an endorsement by the National Wildfire Coordinating Group of any product or service to the exclusion of others that may be suitable.

Comments regarding the content of this publication should be directed to: National Interagency Fire Center, Fire Training, 3833 S. Development Ave., Boise, Idaho 83705. E-mail: [email protected].

Additional copies of this publication may be ordered from National Interagency Fire Center, ATTN: Great Basin Cache Supply Office, 3833 South Development Avenue, Boise, Idaho 83705. Order NFES 2901. PREFACE

Introduction to Wildland Fire Behavior, S-190, is identified training in the National Wildfire Coordination Group’s (NWCG), Wildland and Prescribed Fire Curriculum. This course has been developed by an interagency development group with guidance from the National Interagency Fire Center (NIFC), Fire Training Group under authority of the NWCG, with coordination and assistance of personnel from the following agencies:

Bureau of Land Management Timothy Mathewson

Bureau of Land Management Christine Keavy

National Park Service Patrick Morgan

USDA Forest Service Michelle Ellis

Fire Behavior Committee Liaison Risa Lange-Navaro

NWCG Fire Training Noble Dunn, Deana Parrish, Sue Hickman

The NWCG appreciates the efforts of these personnel, and all those who have contributed to the development of this training product.

i ii CONTENTS

PREFACE ...... i

UNITS OF INSTRUCTION

Unit 0 – Introduction...... 0.1

Unit 1 – Basic Concepts of Wildland Fire...... 1.1

Unit 2 – Principles of Wildland Fire Behavior

Lesson 2A – Topographic Influences ...... 2A.1

Lesson 2B – Fuels...... 2B.1

Lesson 2C – Weather...... 2C.1

Unit 3 – Wildland Fire Behavior and Safety ...... 3.1

iii

iv Introduction to Wildland Fire Behavior, S-190

Unit 0 – Introduction

OBJECTIVES:

During this unit the instructor will:

1. Introduce instructors and students.

2. Discuss administrative concerns.

3. Explain the purpose of the course.

4. Explain the course objectives.

5. Discuss expectations.

6. Explain course evaluation methods.

7. Explain where the course fits in the wildland fire behavior curriculum.

0.1

0.2 I. INTRODUCTIONS

II. ADMINISTRATIVE CONCERNS

III. PURPOSE OF COURSE

To provide the student with wildland fire behavior knowledge applicable for safe and effective fire management activities (wildfires, prescribed fire, and fire use).

This course introduces students to characteristics and interactions of the wildland fire environment (fuels, weather, and topography) that affect wildland fire behavior for safety purposes.

The materials in this course are elements of the wildland fire behavior curriculum.

This is the first formal wildland fire behavior training course the students will receive.

IV. COURSE OBJECTIVES

• Identify and discuss the three sides of the fire triangle.

• Identify the environmental factors of fuels, weather, and topography that affect the start and spread of wildland fire.

• Describe the contributing factors that indicate the potential for increased fire behavior that may compromise safety.

0.3 V. EXPECTATIONS

A. Student Expectations

What are your expectations for the course?

B. Instructor Expectations

• Attendance at all sessions

• Be prepared to start on time

• Participate and share ideas

VI. EVALUATIONS

A. Student Evaluations

Students must obtain 70% or higher on the final exam to receive a certificate of completion for this course.

B. Course Evaluations

This is an opportunity for students to comment on the course and instructors for the purpose of improving future courses.

0.4 VII. WHERE DOES THIS COURSE FIT IN THE WILDLAND FIRE BEHAVIOR CURRICULUM?

A. Introduction to Wildland Fire Behavior, S-190

Entry-level course designed around the basics of fuel, weather, and topography.

B. Intermediate Wildland Fire Behavior, S-290

Provides a better basis for analyzing variables and understanding how they interact and affect wildland fire behavior. Introduces the Fireline Assessment Method (FLAME); a practical fireline tool used for predicting significant short term changes in wildland fire behavior.

C. Introduction to Wildland Fire Behavior Calculations, S-390

Introduces wildland fire behavior calculations by manual methods such as tables and nomograms.

D. Advanced Wildland Fire Behavior Calculations, S-490

Teaches students to use state of the art computer models to project fire perimeter growth based on weather predictions and knowledge of fuels and topography.

0.5

0.6 Introduction to Wildland Fire Behavior, S-190

Unit 1 – Basic Concepts of Wildland Fire

OBJECTIVES:

Upon completion of this unit, students will be able to:

1. Define basic terminology used in wildland fire.

2. Identify the elements of the fire triangle.

3. Describe three methods of heat transfer.

1.1

1.2 I. BASIC TERMINOLOGY USED IN WILDLAND FIRE

A. Parts of the Fire

1. Point of origin

The precise location where a competent ignition source came into contact with the material first ignited and sustained combustion occurred.

2. Head of a fire

The side of the fire having the fastest rate of spread.

3. Flank of a fire

The part of a fire’s perimeter that is roughly parallel to the main direction of spread.

4. Rear of a fire

• That portion of a fire spreading directly into the wind or down slope.

• That portion of a fire edge opposite the head.

• Slowest spreading portion of a fire edge. Also called heel of a fire.

1.3 5. Fire perimeter

The entire outer edge or boundary of a fire.

6. Fingers of a fire

The long narrow extensions of a fire projecting from the main body

7. Pockets of a fire

Unburned indentations in the fire edge formed by fingers or slow burning areas.

8. Island

Area of unburned fuel inside the fire perimeter.

9. Spot fire

Fire ignited outside the perimeter of the main fire by a firebrand.

1.4

1.5 B. Fire Behavior Terms

1. Smoldering

Fire burning without flame and barely spreading.

2. Creeping fire

Fire burning with a low flame and spreading slowly.

3. Running fire

Behavior of a fire spreading rapidly with a well defined head.

4. Spotting

Behavior of a fire producing sparks or embers that are carried by the wind and which start new fires beyond the zone of direct ignition by the main fire.

5. Torching

The burning of the foliage of a single tree or a small group of trees, from the bottom up.

6. Crown fire

A fire that advances from top to top of trees or shrubs more or less independent of a surface fire. Crown fires are sometimes classed as running or dependent to distinguish the degree of independence from the surface fire.

1.6 7. Flare up

Any sudden acceleration in the rate of spread or intensification of the fire. Unlike blowup, a flare-up is of relativity short duration and does not change existing control plans.

8. Firewhirl

Spinning vortex column of ascending hot air and gases rising from a fire and carrying aloft smoke, debris, and flame. Fire whirls range in size from less than one foot to over 500 feet in diameter. Large fire whirls have the intensity of a small tornado.

9. Backing fire

That portion of the fire with slower rates of fire spread and lower intensity, normally moving into the wind and/or down slope. Also called heel fire.

10. Flaming front

That zone of a moving fire where the combustion is primarily flaming.

Behind this flaming zone combustion is primarily glowing or involves the burning out of larger fuels (greater than about 3 inches in diameter).

Light fuels typically have a shallow flaming front, whereas heavy fuels have a deeper front.

1.7 C. Other Useful Firefighting Terms

1. Anchor point

An advantageous location, usually a barrier to fire spread, from which to start constructing a fireline. The anchor point is used to minimize the chance of being flanked by the fire while the line is being constructed.

2. Control line

An inclusive term for all constructed or natural barriers and treated fire edges used to contain a fire.

3. Fireline

The part of a containment or control line that is scraped or dug to mineral soil.

4. Mop-up

Extinguishing or removing burning material near control lines, felling snags, and trenching logs to prevent rolling after an area has burned, to make a fire safe, or to reduce residual smoke.

5. Contained

The status of a wildfire suppression action signifying that a control line has been completed around the fire, and any associated spot fires, which can reasonably be expected to stop the fire's spread.

1.8 6. Controlled

The completion of control line around a fire, any spot fires, and any interior islands to be saved.

Burn out any unburned area adjacent to the fire side of the control lines.

Cool down all hot spots that are immediate threats to the control line, until the lines can reasonably be expected to hold under the foreseeable conditions.

7. Chain

Unit of measure in land survey, equal to 66 feet (20 M) (80 chains equal 1 mile).

Commonly used to report fire perimeters and other fireline distances.

Popular in fire management because of its convenience in calculating acreage (example: 10 square chains equal one acre).

1.9 II. ELEMENTS OF THE FIRE TRIANGLE

Three elements must be present and combined before combustion can occur and continue. There must be:

• Fuel to burn

• Air to supply oxygen for the flame

• Heat to start and continue the combustion process

These three elements or sides compose what we call the “fire triangle.” Remove any single one, and there can be no fire.

III. THREE METHODS OF HEAT TRANSFER

We have learned that heat is a necessary condition for combustion, and part of the fire triangle. There are many methods by which heat can be supplied to a fuel to start a fire. Examples:

• Matches • Lightning • Cigarettes

More importantly, we must know how the fire spreads once it has started.

Heat must be able to move from one burning piece to another, or the fire triangle will be broken. This movement is called heat transfer. Heat is transferred by three processes:

• Radiation • Convection • Conduction

1.10 A. Radiation

Think of radiant heat as a ray or wave. Radiant heat warms you as you stand close to a campfire, or stand in the sunlight. Radiant heat can dry surrounding fuels and sometimes ignite them.

B. Convection

Think of convection as a smoke column above the fire. Convection occurs when lighter warm air moves upward. The hot gases and embers which compose the smoke column can dry and ignite other fuels.

C. Conduction

Think of conduction as a spoon in a hot drink. Heat is conducted from one fuel particle to another in the same way, through direct contact.

Since wood is a poor conductor (meaning heat will not travel through it easily), this process is the least important of the three to fire behavior.

1.11 OPEN BOOK EXERCISE.

1. What are the three methods of heat transfer?

2. The fire triangle consists of oxygen, heat, and ______?

3. When is a fire controlled?

4. Should you fight fire without an anchor point?

Why?

1.12 Introduction to Wildland Fire Behavior, S-190

Unit 2 – Principles of Wildland Fire Behavior

Lesson A – Topographic Influences

OBJECTIVE:

Upon completion of this lesson, students will be able to:

• List the basic characteristics of topography and describe how they affect wildland fire behavior.

2A.1 2A.2 I. TOPOGRAPHY

Topography is the configuration of the earth’s surface including its relief and the position of its natural and man-made features.

It is much easier to predict the influences which topography will have on a wildfire than the influences of fuel and weather.

Following are topographic terms and how they affect wildland fire behavior.

A. Aspect

Aspect is the direction a slope is facing (its exposure in relation of the sun).

The aspect of a slope generally determines the amount of heating it gets from the sun; therefore, determines the amount, condition, and type of fuels present.

1. South and southwest slopes are normally more exposed to sunlight and generally have:

• lighter and sparser fuels • higher temperatures • lower humidity • lower fuel moisture

They are the most critical in terms of start and spread of wildland fires.

2A.3 2. North facing slopes have more shade which causes:

• heavier fuels • lower temperatures • higher humidity • higher fuel moistures

A north facing aspect will have less fire activity than a south facing slope.

B. Slope

The amount or degree of incline of a hillside (a steep slope).

Fires burn more rapidly uphill than downhill. The steeper the slope, the faster the fire burns.

This is because the fuels above the fire are brought into closer contact with the upward moving flames.

Convection and radiant heat help the fuel catch fire more easily.

Another concern about steep slopes is the possibility of burning material rolling down the hill and igniting fuel below the main fire.

The position of the fire in relation to the topography is a major factor in the resulting fire behavior.

A fire on level ground is primarily influenced by fuels and wind.

A fire which starts near the bottom of a slope during normal upslope daytime wind conditions will normally spread faster and has more area to spread upslope than a fire that starts near the top of the slope.

2A.4 C. Shape of the Country – Terrain

Certain topographic features can influence the wind speed and direction for small areas, independent of general weather conditions for an area.

The shape of the country can also influence the direction of fire spread, rate of spread, and the intensity.

D. Box Canyons

Fires starting near the base of box canyons and narrow canyons may react similar to a fire in a wood burning stove or fireplace.

Air will be drawn in from the canyon bottom creating very strong upslope drafts. These upslope drafts create rapid fire spread up the canyon, also referred to as the chimney affect. This affect can result in extreme fire behavior and can be very dangerous.

E. Narrow Canyons

Fire in a steep narrow canyon can easily spread to fuels on the opposite side by radiation and spotting. Wind eddies and strong upslope air movement may be expected at sharp bends in canyon.

F. Wide Canyons

Prevailing wind direction can be altered by the direction of the canyon. Cross-canyon spotting of fires is not common except in high winds. Strong differences in fire behavior will occur on north and south aspects.

2A.5 G. Ridges

Fire burning along lateral ridges may change direction when they reach a point where the ridge drops off into a canyon. This change of direction is caused by the flow of air in the canyon.

H. Saddle

Wind blowing through a saddle or pass in a mountain range can increase in speed as it passes through the constricted area and spreads out on the downwind side with possible eddy action.

I. Elevation

The height of the terrain above mean sea level, usually expressed in feet (ASL - Above Sea Level).

Elevation plays a large role in determining the conditions and amount of fuel.

Because of higher temperatures, fuels at lower elevations dry out earlier in the year than those at higher elevations.

In extremely high elevations there may be no fuel.

Elevation affects fire behavior in several other ways like the amount of precipitation received, wind exposure, and its relationship to the surrounding terrain.

2A.6 J. Barriers

Any obstruction to the spread of fire, typically an area or strip lacking any flammable fuel.

Barriers to fire include many things, both natural and man-made.

1. Natural barriers:

• rivers • lakes • rock • slides

Fuels which have a high moisture content do not burn as well as others in the same area.

2. Man-made barriers:

• roads • highways • reservoirs • fireline constructed by fire resources

2A.7 OPEN BOOK EXERCISE.

1. A barrier is:

2. Under normal conditions, a north facing aspect will have more fire activity than a south facing aspect.

a. True b. False

3. A box canyon is dangerous because:

2A.8 Introduction to Wildland Fire Behavior, S-190

Unit 2 – The Principles of Wildland Fire Behavior

Lesson B – Fuels

OBJECTIVES:

Upon completion of this lesson, students will be able to:

1. Identify the basic fuel types.

2. Identify the fuel characteristics that influence the behavior of the fire.

2B.1 2B.2 I. THE SIX BASIC FUEL TYPES

A. Definition of Fuel

A simple definition of fuel is any burnable material.

• Wildland fuels are basically live and/or dead plant material.

• Houses, sheds, etc., can also be fuels

Fuels are the source of energy that drives the fire.

Regardless of the area of the country, fire behavior is dependent on certain fuel characteristics:

• Fuel type • Fuel loading • Fuel availability

B. Fuel Types

Wildland fuels are grouped into fuel types based on the primary fuel that carries the fire. There are six major fuel types:

• Grass • Grass – Shrub • Shrub • Timber – Understory • Timber litter • Slash - Blowdown

Fuels vary in type from one area of the country to another and within the same area.

Differences in the amount of water in the soil is one reason that types of fuels vary and elevation changes is another.

2B.3 1. Grass

• Found in most areas.

• More dominant as a fuel in desert and range areas.

• Can become prevalent after a fire in timber areas.

• Burns hottest and fastest.

2. Grass – Shrub

• Found in the plains regions and high deserts.

• A significant contributor to fire spread due to the fine fuels mixed with the aerial/shrub fuel.

3. Shrub

• Found throughout most areas.

• Some highly flammable shrub fuels are:

– Palmetto/gallberry in the southeast – Sagebrush in the Great Basin – Chaparral in the southwest and California

4. Timber - Understory

• Found throughout most areas

• Provides ladder to aerial crown fuels

2B.4 5. Timber litter

• Most dominant in mountainous topography, especially in the Northwest.

• Provides fuel for ground fire.

6. Slash - Blowdown

• Debris left after natural events or human activities:

– Logging – Road building – Pruning – Thinning – Shrub cutting – Wind – Fire – Snow

• Debris may include:

– Logs – Chunks of wood – Bark – Branches – Stumps – Broken understory trees – Shrubs

• Provides fuel for fire spread

2B.5 EXERCISE 1.

For your assigned fuel type, answer the following questions on a flip chart:

1. List examples, near your area, where this fuel type occurs.

2. Why is this fuel type a possible concern to firefighters?

II. FUEL CHARACTERISTICS THAT INFLUENCE THE BEHAVIOR OF THE FIRE

A. Fuel Type

B. Fuel Loading

The amount of fuel present expressed quantitatively in terms of weight of fuel per unit area (tons per acre).

• This may be available fuel (consumable fuel) or total fuel and is usually dry weight.

• The loading of the fuels in any given area does not necessarily mean the fire will burn with great intensity.

• What is more important is the quantity of fuels available for combustion.

2B.6 C. Fuel Availability (for combustion)

Many factors are involved when talking about the availability of a fuel for combustion.

1. Fuel size classes and shape

The physical characteristics of fuels, divided into four categories on the basis of their size:

a. 1-hour fuels: 0 – ¼ inch in diameter

b. 10-hour fuels: ¼ – 1 inch in diameter

c. 100-hour fuels: 1 – 3 inches in diameter

d. 1000-hour fuels: 3 – 8 inches in diameter

2. Surface area to volume ratio

• Relates to the amount of the outer surface of the fuel that is exposed to the air.

• The more surface exposed, the more easily the fuel will dry and burn.

• Smaller (fine) fuels have a higher surface area to volume ratio than larger (heavy) fuels.

2B.7 An example to illustrate surface-area-to-volume ratio concepts is the process of building a campfire:

• Start with small fuels (such as dry grass, pine needles, and small twigs), then add larger fuels (such as larger twigs and sticks), and finally add the largest fuel – the logs.

The smaller fuels (grass, needles, etc.) have a larger surface area to volume ratio than the logs, and therefore ignite more readily than the logs.

D. Fuel Arrangement

The manner in which fuels are spread over a certain area.

1. Horizontal continuity

Horizontal continuity affects fire’s rate of spread.

a. Uniform fuels

Include all fuels distributed continuously over the area.

• Areas containing a network of fuels which connect with each other to provide a continuous path for a fire to spread are included in this category.

2B.8 b. Patchy fuels

Include all fuels distributed unevenly over the area, or areas of fuel with definite breaks or barriers present.

Examples:

• Patches of rock outcroppings.

• Bare ground.

• Areas where another dominant type of fuel is much less flammable.

2. Vertical arrangement

a. Ground fuels

All combustible materials lying beneath the surface:

• Deep duff • Tree roots • Rotten buried logs • Other organic material

Ground fire consumes the organic and combustible materials beneath the surface, such as a smoldering duff or peat fire.

2B.9 b. Surface fuels

All combustible materials lying on or immediately above the ground:

• Needles or leaves • Duff • Grass • Small dead wood • Downed logs • Stumps • Large limbs • Low shrubs

Surface fire burns surface litter, debris, small shrubs, and other vegetation. c. Ladder fuels

Combustible materials that aid the spread of fire from the surface to the upper canopy.

• Ladder fuels can include surface litter, shrubs, and other moderate height vegetation that provides a pathway from the surface to the canopy.

d. Aerial fuels

All green and dead materials located in the upper canopy:

• Tree branches and crowns • Snags • Hanging moss • Tall shrubs

Crown fire burns through the tops of trees or shrubs and can advance in conjunction with or be independent of the surface fire.

2B.10 3. Fuel moisture

The amount of water in a fuel, expressed as a percentage of the oven-dry weight of that fuel.

• Fuel moisture is expressed as a percent of total weight.

• How well a fuel will ignite and burn is dependent, to a large extent, on its moisture content.

• Dry fuels will ignite and burn much more easily than the same fuels when they are wet.

– You don’t use wet wood to make a campfire!

• Before a wet fuel can burn, the moisture it contains must evaporate.

– This process requires more heat. As fuel moisture increases, the amount of heat required to ignite and burn that fuel also increases.

• Because of their various sizes and characteristics, different fuels in the same area will have various moisture levels.

• Likewise a similar type of fuel, across a broad area, will have different moisture levels based on the amount of precipitation received and period of warm, dry weather.

Remember, light (small) fuels take on and lose moisture faster than heavier (larger) fuels.

4. Wet fuels

Fuels that have a high moisture content because of exposure to precipitation or high relative humidity.

2B.11 5. Dry fuels

Fuels that have low moisture content because of prolonged exposure to sunshine, dry winds, drought, or low relative humidity.

6. Timelag

The rate at which dead fuel gains or loses moisture.

Time needed under specified conditions for a fuel particle to lose about 63 percent of the difference between its initial moisture content and its equilibrium moisture content.

If conditions remain unchanged, a fuel will reach 95 percent of its equilibrium moisture content after four timelag periods.

Firefighters use a concept of “Timelag” to identify the different sizes of dead fuels as they relate to increasing moisture or drying-out over time.

Smaller fuels can dry out in an hour larger fuels may take ten to a thousand hours to dry.

One-hour timelag fuels react to changes in relative humidity much faster than 100-hour timelag fuels.

The timelag categories are:

1-hour 0 - ¼ inch in diameter 10-hour ¼ - 1 inch in diameter 100-hour 1 - 3 inches in diameter 1000-hour 3 - 8 inches in diameter

2B.12 EXERCISE 2.

Part 1

View each photo and match it to the correct description.

Photo #1: ____ a. These are patchy fuels.

Photo #2: ____ b. This is a large volume of fuel.

Photo #3: ____ c. These are 1-hr timelag fuels.

Photo #4: ____ d. This is a shrub fuel type.

Part 2

Match the definitions to the correct descriptions.

Uniform Fuels ____ A. The amount of water in a fuel, expressed as a percentage of the oven-dry weight of that fuel.

Ladder Fuels ____ B. Grasses, leaves, pine needles

Fuel Timelag ____ C. Fuels distributed continuously over the area.

Light Fuels ____ D. All combustible materials lying on or immediately above the ground.

Fuel Moisture ____ E. The rate at which dead fuel gains or loses moisture.

Surface Fuels ____ F. Combustible materials that aid the spread of fire from the surface to the upper canopy.

2B.13

2B.14 Introduction to Wildland Fire Behavior, S-190

Unit 2 – Principles of Wildland Fire Behavior

Lesson C – Weather

OBJECTIVES:

Upon completion of this lesson, students will be able to:

1. Describe the effect temperature and relative humidity have on wildland fire behavior.

2. Describe the effect of precipitation on wildland fire behavior.

3. Describe the differences between a stable and unstable atmosphere.

4. Describe general and local winds.

5. Describe critical fire weather conditions.

6. List the different types of fire weather forecasts and outlooks available.

2C.1

2C.2 I. WEATHER

Short-term variations in the atmosphere are what we call weather. Weather is one of three components of the fire environment.

Weather conditions can result in the ignition of fire by lightning from thunderstorms and the rapid spread of fires as a result of strong winds. On the other hand, an increase in humidity or precipitation can slow or extinguish fires.

Of the three fire environment components, weather is the most variable over time, and at times, difficult to predict.

Firefighters conducting fire suppression must monitor the weather at all times to make safe and effective firefighting decisions.

The importance of monitoring weather and predicting the resultant fire behavior cannot be overstressed. It is one of the 10 Fire Orders and three of 18 Watchout Situations that all firefighters must obey.

The risk involved in fire suppression can be reduced if firefighters and fire managers pay attention and understand weather conditions that impact fire behavior.

The basic principles and concepts of fire weather as they relate to wildland fire behavior include:

• Air Temperature and Relative Humidity (RH)

• Precipitation

• Atmospheric Stability

• Wind

2C.3 II. THE EFFECT TEMPERATURE AND RELATIVE HUMIDITY HAVE ON WILDLAND FIRE BEHAVIOR

A. Air Temperature

Air temperature is the degree of hotness or coldness of the air.

1. Air temperature varies with:

• Time • Location • Height above the earth’s surface

2. Changes in air temperature near the surface of the earth are caused by:

• Changing seasons • Alternations of night and day • Migrating weather systems

3. Seasonal and diurnal temperature changes can be large or small, depending on:

• Latitude • Elevation • Topography • Proximity to the moderating influences of nearby oceans or lakes

Abrupt changes in temperatures can occur when migrating weather systems transport colder or warmer air into a region.

Heating of the earth’s surface and the atmosphere is primarily a result of solar radiation from the sun; however, on a smaller scale, heat may be caused by a large fire.

2C.4 In the wildland fire environment, direct sunlight and hot temperatures can preheat fuels and bring them closer to their ignition point, whereas cooler temperatures have the opposite affect.

Above average temperatures are common on large fires. Many firefighter fatalities have occurred on fires where record high temperatures were set.

Temperature is measured with a thermometer calibrated either to the Fahrenheit scale or the Celsius scale.

B. Relative Humidity

Relative humidity is the amount of moisture in the air divided by the amount the air could hold when saturated at the same air temperature; usually expressed in percent.

Relative humidity can range from 1% (very dry) to 100% (very moist). Low relative humidity is an indicator of high fire danger.

Moisture in the atmosphere, whether in the form of water vapor, cloud droplets, or precipitation, is the primary weather element that affects fuel moisture content and the resulting flammability of wildland fuels.

The amount of moisture that fuels can absorb from or release to the air depends largely on relative humidity. Light fuels, such as grass, gain and lose moisture quickly with changes in relative humidity. Heavy fuels respond to humidity changes much more slowly.

Firefighters can usually see or feel most of the elements of weather such as:

• Wind • Rain • Increasing temperatures

2C.5 Small changes in relative humidity that cannot be felt or seen can have a significant impact on wildland fire behavior.

Relative humidity values for extreme wildland fire behavior vary over time and location, and are different for different fuels types.

Fuels in the southeast part of the United States and Alaska typically burn with considerably higher relative humidities than fuels in the western U.S.

C. Temperature and Relative Humidity Relationships

Temperature and relative humidity have an inverse relationship.

• When temperature increases, relative humidity decreases.

• When temperature decreases, relative humidity increases.

In the early morning hours, temperature typically reaches its lowest point and relative humidity reaches its highest point. As the sun rises and the temperature increases, relative humidity decreases.

When the temperature reaches its maximum for the day (usually mid to late afternoon) relative humidity decreases to a minimum. This is the time when fine fuel moisture reaches its minimum. As the sun sets the temperature drops and the relative humidity increases.

There can be a large fluctuation of temperature and relative humidity in time and location. However, the majority of large fire outbreaks occur when air temperature is high and relative humidity is low.

It is very important for firefighters to routinely monitor temperature and relative humidity trends. The most common field instrument used to measure and determine these two important weather elements is a sling psychrometer, which is part of the belt weather kit.

2C.6 Exercise 1. Temperature and Relative Humidity

1. Temperature is:

A. The degree of hotness or coldness of a substance.

B. The amount of moisture in the air.

C. The amount of moisture in the air divided by the amount the air could hold when saturated at the same air temperature.

2. Relative humidity is:

A. The degree of hotness or coldness of a substance.

B. The amount of moisture in the air divided by the amount the air could hold when saturated at the same air temperature.

C. Expressed in degrees Fahrenheit.

D. Expressed as a percentage.

E. B and D

3. As temperature increases, relative humidity:

A. Increases

B. Decreases

2C.7 III. THE EFFECT OF PRECIPITATION ON WILDLAND FIRE BEHAVIOR

A. Precipitation

Precipitation is liquid or solid water particles that originate in the atmosphere, and become large enough to fall to the earth’s surface.

B. Precipitation Amount vs. Duration

Fuel moisture is affected by the amount and also the duration of the precipitation.

Fine fuels react quite rapidly by precipitation since they gain or lose moisture usually within one hour.

Heavy fuels are not affected as drastically since they gain or lose moisture more slowly.

A large amount of precipitation in a short time will not raise the fuel moisture as much as less rainfall over a longer period of time where the fuels can absorb more moisture before it runs off.

2C.8 IV. THE DIFFERENCES BETWEEN A STABLE AND UNSTABLE ATMOSPHERE

A. Atmospheric Stability

Wildfires are greatly affected by atmospheric motion and the properties of the atmosphere that affect its motion.

Surface winds, temperature, and relative humidity are most commonly considered and easy to measure in the fire environment.

Less obvious, but equally important, is atmospheric stability and related vertical air movements that influence wildfire.

Atmospheric stability is the degree to which vertical motion in the atmosphere is enhanced or suppressed. Stability is directly related to the temperature distribution of the atmosphere.

The temperature and stability of the atmosphere is constantly changing with variations over time (day-to-day or season-to-season), location, and from one layer of the atmosphere to the next.

B. Stable Atmosphere

A stable atmosphere is defined as an atmosphere that resists upward motion.

In a stable atmosphere, the extensive heat of the fire generates vertical motion near the surface, but the vertical motion above the surface is weakened, thus limiting indrafts into the fire at low levels and fire intensity.

2C.9 C. Visual Indicators of a Stable Atmosphere

In the fire environment, visual indicators can give clues about the stability of the atmosphere. Keeping in mind that stable air resists upward vertical motion, the following are visual indicators of a stable atmosphere:

• Clouds in layers

• Stratus type clouds

• Smoke column drifts apart after limited rise

• Poor visibility due to smoke or haze

• Fog layers

• Steady winds

D. Inversions

The usual temperature structure of the lower atmosphere is characterized by a decrease in temperature with altitude. However, a layer where temperature increases with altitude (warm air over cold air) may exist. This layer is referred to as an inversion.

Warm air ------= Inversion (stable condition) Cold air

Under an inversion, fuel moisture content is usually higher, thus decreasing fire spread rates and intensities.

Updrafts containing smoke and warm gases generated by a fire are typically weak and will only rise until their temperature equals that of the surrounding air. Once this occurs, the smoke flattens out and spreads horizontally.

2C.10 When inversions break or lift, as a result of heating the lower atmosphere by the sun or a fire, increased wildland fire behavior is almost certain.

1. Watch for the following indicators when an inversion breaks:

• Increase in temperature • Decrease in relative humidity • Increase and/or shift in wind

2. There are four types of inversions that may be encountered in the wildland fire environment:

• Nighttime (radiation) • Subsidence • Frontal • Marine

Though all inversions are important, nighttime and subsidence inversions are most common in the wildland fire environment.

E. Nighttime (Radiation) Inversions

Air cooled at night, primarily by contact with cold surfaces, gradually deepens as the night progresses and forms a surface inversion. Inversions forming at night near the earth’s surface are commonly referred to as a radiation or nighttime inversion.

Nighttime inversions develop on calm, clear nights when radiational cooling of the earth’s surface is greatest, and can differ in strength depending on time of year. Inversions in the winter are typically stronger than inversions that develop in the summer.

Nighttime inversions are easy to identify because they trap smoke and gases resulting in poor visibilities in valleys or drainages.

2C.11 F. Thermal Belts

Nighttime inversions in mountainous regions increase in depth during the night. They form early in the evening at the canyon bottom or valley floor and at first are quite shallow. The cold layer gradually deepens, with the nighttime inversion coming in contact with and reaching farther up the slope below the main ridges.

The warmest nighttime air temperatures in valleys are often found at the inversion top. The height of the warmest air temperature, at the top of the inversion, can be found by measuring temperature along the slope. From the top of the inversion, temperature decreases as one goes farther up or down the slope. This region of warmer air, typically found on the middle third of the slope, is called the THERMAL BELT.

The thermal belt is characterized by the highest minimum temperature and the lowest nighttime relative humidity. Within the thermal belt, wildland fires can remain rather active throughout the night. Below the thermal belt, fires are in cool, humid, and stable air.

G. Subsidence Inversion

Subsidence is the large-scale sinking of air associated with high pressure systems. As air from higher elevations in high pressure systems descends to lower elevations, it warms and dries.

The warming and drying of air sinking is so pronounced that saturated air (air with 100% RH), can produce relative humidity less than 5 percent in a very short period of time. If a high pressure system persists for a period of days, the subsidence inversion may reach the surface with only very little external modification or addition of moisture.

Skies are typically clear or cloudless under these high pressure systems, and extended periods of above average temperatures and below average relative humidities can dry out fuels to the point that burning conditions become severe. Subsidence is usually a contributor in the development of foehn winds.

2C.12 H. Unstable Atmosphere

An unstable atmosphere is defined as an atmosphere that encourages upward motion.

When the atmosphere is unstable, vertical motions increase, contributing to increased fire activity by:

• Allowing convection columns to reach greater heights, producing stronger indrafts and convective updrafts.

• Increasing the lofting of firebrands by updrafts.

• Increasing the occurrence of dust devils and fire whirls.

• Increasing the potential for gusty surface winds.

Wildland fires burn hotter and with more intensity when the air is unstable. Cold air over warm air represents an unstable condition.

Cold air ------= Unstable condition Warm air

I. Visual Indicators of an Unstable Atmosphere

• Clouds grow vertically and smoke rises to great heights

• Cumulus clouds

• Good visibility

• Gusty winds

• Dust devils and firewhirls

2C.13 Exercise 2. Atmospheric Stability

1. A stable atmosphere:

A. Encourages upward vertical motion

B. Resists upward motion

2. An unstable atmosphere:

A. Encourages upward vertical motion

B. Resists upward motion

3. An inversion is:

A. A layer of air where temperature increases with altitude.

B. A layer of air where temperature decreases with altitude.

C. A layer of air where there is no temperature change with altitude.

2C.14 V. GENERAL AND LOCAL WINDS

A. Wind and Wind Direction

Wind is the horizontal movement of air relative to the surface of the earth. Wind direction is the direction from which the wind is blowing (a north wind means the wind is blowing from the north).

Wind is the most critical weather element affecting wildland fire behavior, the most difficult to predict, and the most variable in both time and location.

This variability (especially in rough terrain) can pose safety and fire control problems, which can result in firefighter fatalities. Wind direction and wind speed must be constantly monitored by all firefighters.

B. Characteristics of Wind and its Effect on Wildland Fire

Wind impacts the fire environment by:

• Increasing the supply of oxygen to the fire.

• Determining the direction of fire spread.

• Increasing the drying of the fuels.

• Carrying sparks and firebrands ahead of the main fire causing new spot fires.

• Bending flames results in the preheating of fuels ahead of the fire.

• Influencing the amount of fuel consumed by affecting the residence time of the flaming front of the fire. The stronger the wind, the shorter the residence time and the less fuel is consumed.

2C.15 C. Wind Systems

1. General wind

General winds are large scale upper level winds caused by high and low pressure systems.

If strong enough, these winds can influence wildland fire behavior, but are generally modified in the lower atmosphere by terrain.

2. Local wind

Local winds are found at lower levels of the atmosphere.

Local winds are induced by small-scale (local) differences in air temperature and pressure, and are best developed when skies are clear and general winds are weak.

Terrain also has a very strong influence on local winds; the more varied the terrain, the greater the influence.

Local winds can be as important to wildland fire behavior as the winds produced by the large-scale pressure patterns. In many areas, especially in rough terrain or near large bodies of water, local winds can be the prevailing daily winds.

The different types of local winds include:

a. Slope winds

Slope winds are local winds that develop in mountainous terrain where the differences in heating and cooling occur.

During the day, the typical local wind pattern is upslope and downslope during the night. There will be cases where this rule does not apply.

2C.16 Local personnel are usually aware of prevailing wind conditions.

(1) Upslope wind characteristics

The air in the valleys becomes warmer than the air on the mountain top and thus rises, producing the upslope wind.

• The greatest upslope wind speed occurs about mid-afternoon.

• Speeds generally range between 3 and 8 mph and can be gusty.

• East facing slopes receive solar energy at sunrise, thus the downslope to upslope change takes place first on east aspects.

This change can be gradual and may be characterized by a relative calm for an hour or more as the slope heats.

• South and west facing slopes receive heat later in the morning; therefore, the downslope to upslope takes place usually by late morning.

2C.17 (2) Downslope wind characteristics

The air along the mountain tops at night cools faster than the air in the valley. The cool air sinks, producing the downslope wind.

• The greatest downslope flow occurs after midnight.

• Speeds generally range between 2 and 5 mph.

• Relative calm takes place before the downslope wind begins.

• Because east aspects lose solar energy first, the change from upslope to downslope occurs on east aspects early in the afternoon.

• Southwest and west facing slopes receive solar energy through much of the afternoon, thus downslope wind typically begins just after sunset.

• The change in wind from downslope to upslope can rapidly change wildland fire behavior from inactive to active in a matter of minutes.

• Though the steepness of slope also plays a role, stronger upslope winds lead to faster uphill fire spread.

• Downslope winds seldom produce dangerous conditions; however, strong downslope winds, increased by the steepness of the terrain, can result in downhill runs.

2C.18 b. Valley winds

Valley winds are produced by local temperature and pressure differences within the valley or between a valley and a nearby plain.

Though there are exceptions, valley winds flow up-valley during the day and downvalley at night.

(1) Up-valley wind characteristics

As air in the valley warms, temperature and pressure differences within the valley or valley to adjacent plains results in an up-valley wind flow.

• The greatest up-valley winds occur mid to late afternoon.

• Up-valley wind speeds typically range between 10 and 15 mph.

• Because of the large amount of air heated in the valley, up-valley winds develop after the upslope winds.

• Up-valley winds typically continue after sunset.

2C.19 (2) Down-valley wind characteristics

As the valley loses solar heating, the air in the valley cools. The cool air drains down-valley, resulting in the down-valley wind.

• The greatest down-valley winds occur after midnight.

• Down-valley wind speeds typically range between 5 and 10 mph.

• Because of the large amount of air cooling in the valley, down-valley winds typically do not develop until a few hours after dark, and well after the development of the downslope winds. c. Sea and land breezes

(1) Sea breeze

A daytime breeze in which cooler air from high pressure over the coastal waters moves onshore to replace heated air rising above the warmer land mass.

Typical wind speed is between 10 and 20 mph. However, wind speed can attain 20 to 30 mph along the California, Oregon, and Washington coasts.

(2) Land breeze

A light nighttime breeze which originates over the relatively cool land, flows out over the warmer coastal waters. Typical wind speed is between 3 and 10 mph.

2C.20 Exercise 3. Winds

1. General winds are:

A. Found at lower levels of the atmosphere and are induced by small- scale (local) differences in air temperature and pressure.

B. Large scale upper level winds caused by high and low pressure systems.

C. Local winds that develop in mountainous terrain where the differences in heating and cooling occur.

2. The different types of local winds include (circle all that apply):

A. upslope wind B. downslope wind C. upvalley wind D. jet stream E. sea-breeze

2C.21 VI. CRITICAL FIRE WEATHER CONDITIONS

Fire seasons occur at different times of the year in different regions of the country, depending on seasonal variations in weather.

The typical fire season at any given location has numerous hot and dry days, yet wildfires are usually clustered within relatively short periods.

These periods are characterized by one (or a combination of) critical fire weather conditions:

• Strong and shifting wind

• Very low relative humidity

• High temperature

• Unstable atmosphere

• Dry lightning

Examples of weather phenomena in which one or more of these critical fire weather conditions may occur:

• Cold fronts

• Foehn winds

• Thunderstorms

• Dust devils

• Firewhirls

2C.22 A. Cold Fronts

A cold front is the boundary line between two different air masses, with cooler air behind the front and warmer air ahead of the front. The two differing air masses result in pressure differences that can lead to moderate or strong wind speed.

Frontal winds associated with frontal passages are particularly dangerous, not only for the strength of the wind, but also the shift in direction as the front approaches and passes through the area.

Along with the shifting winds, atmospheric stability ahead of and behind the front also impacts the fire environment. Unstable conditions encouraging upward motion are typically found ahead and along the frontal boundary. Stable conditions discouraging upward motion are typical behind the front.

Historically, firefighter fatalities have occurred in the pre-frontal environment where winds are strong and shifting, and the atmosphere is unstable.

1. Potentially dangerous cold front characteristics:

• Light southeasterly winds are common several hundred miles ahead of the front.

– Just ahead or along the front, moderate to strong southwesterly winds are common. The strong southwesterly flow ahead of the front will drive the fire head to the northeast.

• The air mass ahead of the front is typically very warm and unstable, resulting in an increase in fire behavior.

2C.23 • Relative humidities can be low or high depending on the origin or location of the system.

– High relative humidities ahead of the front are more common over the eastern U.S. than the western U.S.

• As the front pushes through, the wind can abruptly shift from southwest to northwest, driving the fire head to the southeast.

– This can be a great concern to firefighters due to the increased fire behavior on the south flank of the fire as the winds shift.

• The air mass behind the front is cooler, more stable, and relative humidities are higher, thus fire activity typically decreases.

• Wind speeds just ahead, along, and behind the front typically range from 15 to 30 mph, and can be gusty.

2. Cold front indicators:

• A line of cumulus clouds may be seen approaching from the west or northwest.

• Large clouds of dust can precede the arrival of a cold front.

• Winds normally shift from the southeast to the south, to the southwest, and increase in velocity before the arrival of the front.

• Winds will be strongest and gusty as the front reaches you.

• Winds will continue to shift as the front passes, generally resulting in strong, gusty, cool wind out of the northwest.

2C.24 B. Foehn Winds

Foehn winds are strong, dry winds caused by the compression of air as it flows down the lee side of a mountain range. It is usually, but not always, warm for the season.

Foehn winds can persists for days and frequently reach speeds of 40- 60 mph but can be as high as 90 mph. The relative humidity will usually drop with the onset of foehn winds.

The combination of high wind speeds and low relative humidity can cause high rates of fire spread. When a foehn wind occurs after a long period of dry weather, wildland fire behavior can be extreme.

Common foehn winds in the western U.S. are:

1. Chinook wind: Found along the east side of the Rockies and east side of the Sierra Nevada.

2. Wasatch wind: Found on the west side of the Wasatch Range in Utah.

3. Santa Ana and Sundowner: Southern California.

4. Mono and North wind: Central and Northern California.

5. East wind: Western Washington and Western Oregon.

2C.25 C. Thunderstorms

A storm is produced by a cumulonimbus cloud and always accompanied by lightning and thunder.

1. Thunderstorms can also produce:

• Strong gust winds • Heavy rain • Hail (sometimes)

Thunderstorms are usually of short duration, seldom over 2 to 3 hours for any one storm.

2. The direction of thunderstorm movement is generally in the direction of the winds aloft.

• The direction of thunderstorm movement can be determined by the direction the anvil shaped top is pointing.

3. Downdraft winds from thunderstorms that reach the ground usually spread radially in all directions.

• These wind velocities will often be 25 to 35 mph and can reach as high as 70 mph.

• Surface winds from a thunderstorm will be the strongest in the direction the thunderstorm is moving.

• Thunderstorm wind speed and direction can be altered by topography and vegetation.

2C.26 4. Thunderstorms are potentially dangerous to firefighters because:

• Wind associated with thunderstorms, whether indrafts or downdrafts, can change direction and speed, resulting in sudden changes in the rate and direction of a fire, as well as fire intensity.

• Heat rising from a fire can form a convection column strong enough to trigger the development of a thunderstorm, even on an otherwise cloudless day.

• Thunderstorms, as a result of a convection column, can produce dangerous downdrafts.

• Thunderstorms produce dangerous lightning that results in new starts. Lightning is also a safety problem and can result in death.

2C.27 D. Dust Devils and Firewhirls

Dust devils are one of the most common indicators of unstable air. They occur on hot days over dry ground when skies are clear and the winds are light.

Under intense heating, air near the ground rises in upward-spiraling motions in columns or chimneys.

Firewhirls, generated by intense fires, have been known to twist off trees more than 3 feet in diameter.

They can pick up large burning embers and spew them far across the fireline causing numerous spot fires.

In some extreme cases, firewhirls and dust devils have moved across safe zones, and burned and turned over vehicles.

• The size of dust devils can range from 10 feet to over 100 feet in diameter with heights from 10 feet to 3,000 or 4,000 feet.

• Wind speeds in dust devils are often more than 20 mph and in some extreme cases have exceeded 70 mph.

• A favorite area for firewhirl development is on the wind sheltered (leeward) side of ridges.

2C.28 Exercise 4. Critical Fire Weather

1. Chinook and Santa Ana winds are examples of:

A. A foehn wind

B. A cold front wind

C. A thunderstorm wind

D. A sea-breeze

2. Cold front winds:

A. Are strong, dry winds caused by the compression of air as it flows down the lee side of a mountain range.

B. Are winds associated with a boundary between two dissimilar air masses.

C. A and B.

2C.29 VII. DIFFERENT TYPES OF FIRE WEATHER FORECASTS AND OUTLOOKS AVAILABLE

A. Predictive Services

Predictive Services is a combined group of Interagency Land Management Fire Intelligence Coordinators or Fire Behavior Analysts (FBAN), and Fire Meteorologists.

1. Predictive Services monitors, analyzes, and predicts:

• Fire weather

• Fire danger

• Interagency fire management resource impact

2. Predictive Service products and services:

• Seasonal assessments

• 7 Day Significant Fire Potential

• Monthly Fire Weather/Fire Danger Outlook

• Weather briefings

• Daily summaries of National Weather Service fire weather forecasts, both graphical and text.

• Long term precipitation monitoring

• Smoke management summaries

2C.30 B. National Weather Service (NWS)

There are over 120 National Weather Service offices nationwide that provide a variety of different types of forecasts.

Another major NWS program includes the fire weather program.

NWS standardized products include:

1. Fire Weather Planning Forecasts (FWF)

These forecasts can be in tabular or narrative format.

They include a discussion of the upcoming weather and highlights of any critical fire weather events, as well as many different forecasted elements including:

• Sky/weather

• Temperature

• Relative humidity

• Wind

2. Spot forecasts

A spot forecast is a site specific 24- to 36-hour forecast issued to fit time, topography, and weather of a specific location.

2C.31 3. Fire Weather Watches / Red Flag Warnings

A fire weather watch or red flag warning is issued when the combination of dry fuels and weather conditions support extreme fire behavior or ignition is occurring or expected to occur.

a. Fire Weather Watch

Issued when there is a high potential for the development of a Red Flag Event.

A Fire Weather Watch is normally issued 24 to 72 hours in advance of the expected onset of criteria.

b. Red Flag Warning

Is used to warn of an impending or occurring Red Flag event.

Its issuance denotes a high degree of confidence that a Red Flag event will occur in 24 hours or less.

Exercise 5. Types of Fire Weather Products

1. The seasonal assessment product is issued by:

A. The National Weather Service B. Predictive Services C. Both A and B

2. Red Flag Warnings are issued by:

A. The National Weather Service B. Predictive Services C. Incident Management Teams

2C.32 Introduction to Wildland Fire Behavior, S-190

Unit 3 – Wildland Fire Behavior and Safety

OBJECTIVES:

Upon completion of this unit, students will be able to:

1. Identify indications that fire behavior may be increasing.

2. Describe combined influences that may cause extreme fire behavior and safety concerns.

3. List seven fire environment factors to be aware of while monitoring fire behavior.

3.1 3.2 I. MONITORING FIRE BEHAVIOR

A. Large Fire Indicators

Fires rarely just go from small fires to extreme “blow ups.” There are indicators that, if monitored, will show when a fire is starting to transition from problem fire behavior to extreme fire behavior.

B. Problem vs. Extreme Fire Behavior

1. Problem fire behavior

Fire activity that presents potential hazard to fireline personnel if the tactics being used are not adjusted. The prediction or anticipation of fire behavior is the key to good tactical decisions and safety.

2. Extreme fire behavior

The highest level of problem fire behavior can be described with specific elements:

• Rapid rate of spread • Intense burning • Spotting • Crowning

C. Incident Response Pocket Guide

Use the Incident Response Pocket (IRPG) as a field reference to help monitor changing conditions. The pages of the Operational section are green and placed in the front for quick reference in the field.

The Operational section is where the seven fire environment factors of Look Up, Down and Around are located. Each factor lists indicators to help individuals monitor the fire environment and become more aware of changes that are occurring.

3.3 II. THE SEVEN FIRE ENVIRONMENT FACTORS OF LOOK UP, DOWN AND AROUND

The fire environment is the conditions, influences, and modifying forces that control fire behavior. The fire environment has been described with a triangle showing weather, fuels, and topography (terrain).

There are seven factors within this fire environment that fireline personnel must monitor:

• Fuel Characteristics • Fuel Moisture • Fuel Temperature • Topography (Terrain) • Wind • Atmospheric Stability • Fire Behavior

These seven factors and their corresponding indicators help provide clues when monitoring the fire and anticipating what might happen.

A. Fuel Characteristics

1. Continuous fine fuels

Fire is able to change and spread rapidly in these fuels, especially when combined with slope and/or wind.

2. Heavy loading of dead and down

Large amounts of readily available fuel.

3. Ladder fuels

Allow the fire to readily spread into the canopy, launching firebrands (spots) into the air.

3.4 4. Tight crown spacing

Allows fire to move from bush to bush (or tree to tree) easier.

5. Special conditions

a. Firebrand sources

Burning material that is carried by the wind ahead of the fire or outside of control lines.

Potential firebrand sources are:

• pine bark plates • manzanita leaves • eucalyptus leaves • maple leaves • oak leaves

b. Numerous snags

Fire can become established in these dead or partially dead trees, making them very hazardous. These can launch firebrands into the air as well as fall across control lines.

c. Frost and bug kill

More available fuel to be consumed by the fire.

d. Preheated canopy

Caused by a lower intensity fire burning the fuels near the ground. Heat from the fire dries the fuels above it, making those fuels available to burn.

3.5 e. Unusual fine fuels

Light flashy fuels mixed with high energy fuels, such as continuous grass mixed with sage.

f. High dead to live ratio

Greater amounts of potentially available fuel.

B. Fuel Moisture

1. Low RH (<25%)

The lower the humidity, generally, the more available the fine fuels are to carry fire.

The 25% RH indicator is a general threshold for much of the U.S. In the East, Alaska, and Hawaii, the threshold is generally higher.

2. Low 10 hr FMC (< 6%)

10 hour fuels are just one good indicator of how available fuels are to burn.

3. Drought conditions and seasonal drying

Both are indicators that fuels are more receptive to ignition and carrying the spread of fire.

3.6 C. Fuel Temperature

1. High temps (> 85° F)

Increasing the temperature of the fuels closer to the point of ignition.

2. High percent of fuels with direct sun

On any given slope, are a majority of the fuels in the sun or the shade?

3. Aspect fuel temperature increasing

Which slopes tend to have higher fuel temperatures in the morning? Which are higher in the afternoon? Why is this important?

a. South and southwest slopes:

• Are normally more exposed to sunlight.

• Generally have lighter and sparser fuels.

• Have higher temperatures, lower humidity, and lower fuel moisture.

• Are the most critical in terms of start and spread of fire.

b. North facing slopes have more shade, which causes:

• Heavier fuels • Lower temperatures • Higher humidity • Higher fuel moistures

Being aware of which slopes are “hotter” throughout the day allows firefighters to monitor where the potential for the greatest fire behavior is.

3.7 D. Topography (Terrain)

1. Steep slopes (>50%)

Provides for rapid rates of fire spread due to convective heating and increased potential for rollouts below the fire.

2. Chutes – Chimneys

Provides potential for rapid rates of fire spread by combining steep terrain with updrafts of air.

3. Saddles

Fire is pushed faster through these during uphill runs.

4. Box canyons

All provide for rapid rates of fire spread due to the channeling of wind and heat.

5. Narrow canyons

a. Radiant and convective heating could increase spotting across the canyon.

b. Fire can burn down to the bottom of the canyon and then crossover to the other side. This is known as “slope reversal.”

3.8 E. Wind

Wind is the primary factor that influences fire spread.

1. Surface winds above 10 mph

These winds help determine the direction of fire spread, help to carry firebrands ahead of the fire, and increase the supply of oxygen to the fire.

2. Lenticular clouds

Indicates high winds aloft with the potential to surface.

3. High, fast moving clouds

Indicates a potential for wind shifts.

4. Approaching cold fronts

Wind will increase in speed and change direction with the advance of a cold front.

5. Cumulonimbus development

Indicates possible wind speed and direction and potential for erratic winds.

6. Sudden calm

Be alert for a wind change.

3.9 7. Battling or shifting winds

Winds that change direction and go back to the original direction are battling. This is an indication of a probable change in wind speed and direction.

Changes in wind speed and direction affect everyone on the fire from individual firefighters to fire managers on many portions of the fire.

A sudden change in wind direction can cause firebrands to cross control lines. Increasing winds could cause previously quiet parts of the fire to increase in intensity.

F. Atmospheric Stability

Indicators of an unstable atmosphere and the potential for large fire growth:

1. Good visibility

2. Gusty winds and dust devils

3. Cumulus clouds

4. Castellatus clouds in the a.m.

5. Smoke rises straight up

6. Inversion beginning to lift

This is an indication of a transition from a stable to an unstable atmosphere and the potential for fire growth.

7. Thermal belt

An area of lower nighttime relative humidity and higher temperatures. Fires will generally burn more actively in these areas at night.

3.10 G. Fire Behavior

Indicators of a rapidly changing, wind-driven fire with intense burning:

1. Leaning column

2. Sheared column

3. Well-developed column

4. Changing column

Fire behavior is usually increasing.

5. Trees torching

The fire is beginning to transition from a surface fire to a crown fire. Observe if just one tree is torching or small groups of trees are catching fire. Note if there is wind present and how fast it is blowing.

6. Smoldering fires picking up

Fire behavior is increasing. What else might be occurring to cause this? It is possible that the:

• Inversion is lifting

• Wind is increasing

• Shading has decreased on that aspect and temperature is increasing

• Relative humidity has decreased

3.11 7. Small firewhirls beginning

The fire is increasing in intensity.

8. Frequent spot fires

The fire is spreading and increasing in complexity

H. Review the Seven Fire Environment Factors

• Important to not just monitor one or two factors but all of them.

• Equally important to monitor the trends of each indicator as well.

EXERCISE.

List the seven fire environment factors.

3.12 A publication of the National Wildfire Incident Response Coordinating Group Pocket Guide

PMS 461 April 2018 NFES 001077

SIZEUP REPORT

• Incident Type (wildland fire, vehicle accident, hazmat spill, search and rescue, etc.) • Location/Jurisdiction

• Incident Size • Incident Status • Establish IC and Fire Name • Weather Conditions

• Radio Frequencies • Best Access Routes • Assets/Values at Risk • Special Hazards or Concerns • Additional Resource Needs

This reference is intended to assist in reporting key information regarding incident conditions when first arriving on scene. All agencies will have specific information requirements that may involve additional reports. Incident Response Pocket Guide April 2018 PMS 461 NFES 001077

The Incident Response Pocket Guide (IRPG) establishes standards for wildland fire incident response. The guide provides critical information on operational engagement, risk management, all hazard response, and aviation management. It provides a collection of best practices that have evolved over time within the wildland fire service. The IRPG does not provide absolute solutions to the unlimited number of situations that will occur. Some fireline decisions may be relatively simple; many are not. These decisions often require individual judgment and creativity — skills developed through extensive training, dedicated practice, and experience

The National Wildfire Coordinating Group (NWCG) provides national leadership to enable interoperable wildland fire operations among federal, state, tribal, territorial, and local partners. NWCG operations standards are interagency by design; they are developed with the intent of universal adoption by the member agencies. However, the decision to adopt and utilize them is made independently by the individual member agencies and communicated through their respective directives systems. 2018 Revision Summary This edition reflects feedback and input received since the 2014 version. Therefore, the cover color has been changed to purple. The notable changes include: New References Smoke Hazards and Mitigations Smoke and Transportation Safety Principles of Airtanker and Water Scooper Use Recommended Retardant Coverage Levels Important Winds to Firefighters Alignments and Patterns for Dangerous Fire Behavior Helicopter Extraction Operations Deleted References Flight Following Working with Airtankers Severe Fire Behavior Potential Related to RH and Fuel Moisture Content Existing References with Significant Changes Added Assets/Values at Risk to Size Up Report Added LCES to Briefing Checklist Revised Look Up, Down, and Around Added Critical Burn Period to Common Denominators of Fire Behavior on Tragedy Fires Emphasized effects of slope and wind on Safety Zones Updated Wildland Urban Interface Firefighting Removed the 30/30 Rule in Thunderstorm Safety Edited Last Resort Survival Updated Aviation User Checklist Revised Retardant Use Reminders Updated Directing Retardant and Bucket Drops Updated Spot Weather Forecast information Updated Medical section including the Medical Incident Report IRPG i Table of Contents 2018 Revision Summary ...... i Operational Leadership...... vi Communication Responsibilities...... x Leader’s Intent ...... x Human Factor Barriers to Situation Awareness ...... xi After Action Review (AAR) ...... xiii OPERATIONAL ENGAGEMENT – green pages ...... 1 Risk Management...... 1 Planning for Medical Emergencies ...... 2 Look Up, Down and Around ...... 3 Common Denominators of Fire Behavior on Tragedy Fires ...... 5 Common Tactical Hazards ...... 6 LCES ...... 7 Safety Zones ...... 8 Downhill Checklist ...... 9 Indicators of Incident Complexity ...... 10 Wildland Urban Interface Firefighting ...... 12 SPECIFIC HAZARDS – gray pages ...... 19 How to Properly Refuse Risk ...... 19 Thunderstorm Safety ...... 21 Hazard Tree Safety ...... 22 Powerline Safety ...... 24 Roadside Response Safety ...... 26 Unexploded Ordnance Safety ...... 27 Oil and Gas Site Safety ...... 28 Smoke Hazards and Mitigation ...... 30 Smoke and Transportation Safety ...... 31

IRPG ii Last Resort Survival ...... 32 ALL HAZARD RESPONSE – yellow pages ...... 35 Vehicle Accident Operations ...... 35 HazMat Incident Operations...... 36 HazMat Isolation Distances ...... 37 HazMat Classification for Fixed Facilities ...... 38 Local Disaster Response ...... 39 All Hazard Incident Response ...... 40 Structure Hazard Marking System ...... 41 Missing Person Search Urgency ...... 42 AVIATION – blue pages ...... 45 Aviation User Checklist ...... 45 Aviation Watch Out Situations ...... 46 Helicopter Passenger Briefing and PPE...... 47 Helicopter Landing Area Selection ...... 50 One-Way Helispot ...... 51 Two-Way Helispot ...... 52 Longline Mission ...... 53 Helicopter Hand Signals ...... 54 Paracargo Operations Safety ...... 55 Weight Estimates ...... 56 Aerial Retardant Safety ...... 57 Directing Retardant and Bucket Drops ...... 58 Principles for Airtanker and Water Scooper Use ...... 59 Retardant and Suppressant Use Reminders ...... 60 Recommended Retardant Coverage Levels ...... 61 Aircraft Mishap Response Actions ...... 62 SAFECOM Reporting System ...... 63 OTHER REFERENCES – white pages ...... 65 Spot Weather Forecast ...... 65 IRPG iii Weather Watch/Weather Warning ...... 67 Energy Release Component (ERC) ...... 67 Burning Index (BI) ...... 67 Haines Index (HI) ...... 68 Keetch-Byram Drought Index (KBDI) ...... 68 Lightning Activity Level (LAL) ...... 69 Important Winds to Firefighters ...... 70 Beaufort Scale ...... 72 Alignments and Patterns for Dangerous Fire Behavior ... 73 Fire Behavior Hauling Chart ...... 75 Relative Humidity: 1,400-4,999’ Elevation ...... 76 Relative Humidity: 5,000-9,200’ Elevation ...... 77 Probability of Ignition Tables ...... 78 Strategy – Direct Attack ...... 82 Strategy – Indirect Attack ...... 83 Fireline Location ...... 84 Procedural Felling Operations ...... 85 Working with Heavy Equipment ...... 86 Water Delivery Information ...... 87 Engine ICS Typing ...... 88 Water Tender ICS Typing ...... 88 High Pressure Pump Information ...... 89 Troubleshooting a High Pressure Pump ...... 91 Average Perimeter in Chains ...... 94 Fire Size Class ...... 94 Line Spike ...... 95 Minimum Impact Suppression Tactics ...... 97 Reporting Fire Chemical Introductions ...... 99 Fire Origin Protection Checklist ...... 100 Media Interviews ...... 101 IRPG iv Phonetic Alphabet ...... 102 EMERGENCY MEDICAL CARE– red pages ...... 105 Emergency Medical Care Guidelines ...... 105 Patient Assessment ...... 106 Specific Treatments ...... 107 CPR ...... 108 Heat-Related Injury ...... 109 Burn Injuries ...... 111 Multi-Casualty Triage System ...... 113 Injury/Fatality Procedures ...... 114 Helicopter Extraction Operations ...... 116 Medical Incident Report ...... 118 Sizeup Report ...... front cover (inside) Briefing Checklist ...... back cover (inside) Standard Firefighting Orders ...... back cover (outside) Watch Out Situations ...... back cover (outside)

IRPG v Operational Leadership

The most essential element of successful wildland firefighting is competent and confident leadership.

Leadership means providing purpose, direction, and motivation for wildland firefighters working to accomplish difficult tasks under dangerous, stressful circumstances.

In confusing and uncertain situations, a good operational leader will:

• TAKE CHARGE of assigned resources. • ASSESS SITUATION by gaining intel. • MOTIVATE firefighters with a “can do safely” attitude.

• DEMONSTRATE INITIATIVE by taking action in the absence of orders. • COMMUNICATE by giving specific instructions and asking for feedback.

• SUPERVISE at the scene of action.

IRPG vi DUTY

Be proficient in your job, both technically and as a leader • Take charge when in charge. • Adhere to professional standard operating procedures. • Develop a plan to accomplish given objectives. Make sound and timely decisions • Maintain situation awareness in order to anticipate needed actions. • Develop contingencies and consider consequences. • Improvise within the leader’s intent to handle a rapidly changing environment. Ensure tasks are understood, supervised, and accomplished • Issue clear instructions. • Observe and assess actions in progress without micro- managing. • Use positive feedback to modify duties, tasks, and assignments when appropriate. Develop your subordinates for the future • Clearly state expectations. • Delegate tasks that you are not required to do personally. • Consider individual skill levels and developmental needs when assigning tasks.

IRPG vii RESPECT

Know your subordinates and look out for their well-being • Put the safety of your subordinates above all other objectives. • Take care of your subordinates needs. • Resolve conflicts between individuals on the team. Keep your subordinates informed • Provide accurate and timely briefings. • Give the reason (intent) for assignments and tasks. • Make yourself available to answer questions at appropriate times. Build the team • Conduct frequent debriefings with the team to identify lessons learned. • Recognize individual and team accomplishments and reward them appropriately. • Apply disciplinary measures equally. Employ your subordinates in accordance with their capabilities • Observe human behavior as well as fire behavior. • Provide early warning to subordinates of tasks they will be responsible for. • Consider team experience, fatigue, and physical limitations when accepting assignments.

IRPG viii INTEGRITY

Know yourself and seek improvement • Know the strengths and weaknesses in your character and skill level. • Ask questions of peers and superiors. • Actively listen to feedback from subordinates. Seek responsibility and accept responsibility for your actions • Accept full responsibility for poor team performance. • Credit subordinates for good performance. • Keep your superiors informed of your actions. Set the example • Share the hazards and hardships with your subordinates. • Don’t show discouragement when facing setbacks. • Choose the difficult right over the easy wrong.

IRPG ix Communication Responsibilities All firefighters have five communication responsibilities: • Brief others as needed • Debrief your actions • Communicate hazards to others • Acknowledge messages • Ask if you don’t know

Leader’s Intent In addition, all leaders of firefighters have the responsibility to provide complete briefings and ensure that their subordinates have a clear understanding of their intent for the assignment: • Task = What is to be done • Purpose = Why it is to be done • End State = How it should look when done

IRPG x Human Factor Barriers to Situation Awareness

Low Experience Level with Local Factors • Unfamiliar with the area or the organizational structure.

Distraction from Primary Task • Radio traffic • Conflict • Previous errors • Collateral duties • Incident within an incident

Fatigue • Carbon monoxide • Dehydration • Heat stress • Poor fitness level can reduce resistance to fatigue • 24 hours awake affects your decision making capability like .10 blood alcohol content

IRPG xi Stress Reactions • Communication deteriorates or grows tense • Habitual or repetitive behavior • Target fixation – Locking into a course of action; whether it makes sense or not, just try harder • Action tunneling – Focusing on small tasks, but ignoring the big picture • Escalation of commitment – Accepting increased risk as completion of task gets near

Hazardous Attitudes • Invulnerable – That can’t happen to us • Anti-authority – Disregard of the team effort • Impulsive – Do something even if it’s wrong • Macho – Trying to impress or prove something • Complacent – Just another routine fire • Resigned – We can’t make a difference • Group Think – Afraid to speak up or disagree

IRPG xii After Action Review (AAR)

The climate surrounding an AAR must be one in which the participants openly and honestly discuss what transpired, in sufficient detail and clarity, so everyone understands what did and did not occur and why.

Most importantly, participants should leave with a strong desire to improve their proficiency.

• An AAR is performed as immediately after the event as possible by the personnel involved. • The leader’s role is to ensure skilled facilitation of the AAR. • Reinforce that respectful disagreement is okay. Keep focused on the what, not the who. • Make sure everyone participates. • End the AAR on a positive note.

What was planned? What actually happened? Why did it happen? What can we do next time? (Correct weaknesses/sustain strengths)

IRPG xiii OPERA TIONA L ENG AG EMENT – green pages Risk Management Identify Hazards (Situation Awareness) • Gather Information □ Objective(s) □ Previous Fire Behavior □ Communication □ Weather Forecast □ Who’s in Charge □ Local Factors • Scout the Fire Assess Hazards • Estimate Potential Fire Behavior Hazards □ Look Up/Down/Around Indicators • Identify Tactical Hazards □ Watch Outs • As conditions change, what other safety hazards are likely to exist? • Consider probability versus severity? Develop Controls and Make Risk Decisions • Develop control measures that reduce risk: □ Firefighting Orders  LCES Anchor Point - Downhill Checklist (if applicable) □ What- other controls are necessary? Engineering/Administrative - PPE - Educational - Avoidance □ Emergency- Medevac Procedures/Plan • Are controls in place to mitigate risk? □ NO - Reassess situation □ YES - Next question • Are selected tactics based on expected fire behavior? □ NO - Reassess situation □ YES - Next question • Have instructions been given and understood? □ NO - Reassess situation □ YES - Next question • Consider risk versus gain Implement Controls • Ensure controls are in place and being implemented by personnel. • Ensure controls are integrated into operational plan and understood at all levels. Supervise and Evaluate • Are controls adequately mitigating the hazards? □ NO – Reassess and consider: - Human Factors: o Low experience level? o Distracted from primary tasks? o Fatigue or stress reaction? o Unsafe attitude? - The Situation: o What is changing? o Are strategy and tactics working? If the situation changes significantly, restart Risk Management Process at the appropriate step IRPG – Operational Engagement 1

Planning for Medical Emergencies Prior to each operational period, Incident Commanders, supervisors, and all wildland firefighters need to ask and be able to answer the following three questions: 1. What are we going to do if someone gets hurt? • Are there personnel on your crew/division/fire that can provide medical support? • What type of equipment is available to treat and transport injured personnel? 2. How will we get them out of here? • Could you get an injured firefighter to a road or to a helispot? • How many personnel and what kind of equipment would you need to get an injured firefighter out? 3. How long will it take to get them to a hospital? • Where is the closest hospital? • Will you use air or ground transportation? • Could conditions change and affect the transportation timeline? - Smoke/clouds/nightfall - Fire behavior - Mechanical failures All operational activities should be based on answers to these questions. If the answers are insufficient, stop, reassess, and consider alternate strategies and tactics.

IRPG – Operational Engagement 2

Look Up, Down and Around Fire Environment Indicators Factors

Fuel • Substantial amounts of cured or curing Characteristics fine fuel/continuous • Heavy dead and down • Tight crown spacing (<20 ft.) • Unusual low live and dead fuel moisture values (locally defined) • Special conditions □ Efficient firebrand sources □ Numerous snags □ Preheated canopy □ Frost and bug-kill □ High dead-to-live ratio Topography • Steep slopes (> 45%) • Chutes/chimneys/passes/saddles • Box and narrow canyons Weather • Wind □ Speeds above 10 mph □ Lenticular clouds □ Fast moving clouds □ Cold frontal passages indicated by weak vortices and fluctuating temperatures □ Cumulonimbus clouds □ Dust cloud approaching □ Sudden calm □ Battling or shifting wind

IRPG – Operational Engagement 3

Look Up, Down and Around (continued) Fire Environment Indicators Factors Weather • Atmospheric Instability □ Good visibility □ Battling or shifting wind □ Dust devils □ Cumulus clouds □ Castellanus clouds in the a.m. □ Smoke rises straight up □ Inversion begins to lift □ Unusually high Haines values for the local area • Temp/RH □ Above normal temperatures □ Critically low humidity based on local thresholds Plume • Well developed, nearly vertical column Dynamics • Formation of a large ice cap/ pyrocumulus cloud • Thunder heard/lightning flashes • Sprinkles of rain • Sudden calm • Changing column with alternating strengthening inflows and outflows • Becoming hazy with smoke at your feet

Rapidly • Smoldering fires pick up Changing • Trees begin to torch Behavior • Fire whirls beginning • Leaning or sheared column • Frequent spot fires

IRPG – Operational Engagement 4

Common Denominators of Fire Behavior on Tragedy Fires There are five major common denominators of fire behavior on fatal and near-fatal fires. Such fires often occur: 1. On relatively small fires or deceptively quiet areas of large fires. 2. In relatively light fuels, such as grass, herbs, and light brush. 3. When there is an unexpected shift in wind direction or in wind speed. 4. When fire responds to topographic conditions and runs uphill. 5. Critical burn period between 1400 and 1700. Alignment of topography and wind during the critical burning period should be considered a trigger point to reevaluate tactics. Blowup to burnover conditions generally occur in less than 60 minutes and can be as little as 5 minutes. A tactical pause may be prudent around 1400 for reevaluating your situational awareness of topography, weather, and fuel.

IRPG – Operational Engagement 5

Common Tactical Hazards

Position • Building fireline downhill. • Building undercut or mid-slope fireline. • Building indirect fireline or unburned fuel is between you and the fire. • Attempting frontal assault on the fire or you are delivered by aircraft to the top of the fire. • Establishing escape routes that are uphill or difficult to travel.

Situation • Poor communication due to a rapidly emerging small fire or an isolated area of a large fire. • Suppression resources are fatigued or inadequate. • Assignment or escape route depends on aircraft support. • Nighttime operations. • Wildland Urban Interface operations.

When selected tactics put firefighters in these positions or situations, a higher level of risk is involved. Consider additional hazard controls that may be needed.

IRPG – Operational Engagement 6

LCES LCES must be established and known to ALL firefighters BEFORE it is needed. Lookout(s) • Experienced, competent, trusted • Enough lookouts at good vantage points • Knowledge of crew locations • Knowledge of escape and safety locations • Knowledge of trigger points • Map, weather kit, watch, IAP Communication(s) • Radio frequencies confirmed • Backup procedures and check-in times established • Provide updates on any situation change • Sound alarm early, not late Escape Route(s) • More than one escape route • Avoid steep uphill escape routes • Scouted for loose soils, rocks, vegetation • Timed considering slowest person, fatigue, and temperature factors • Marked for day or night • Evaluate escape time vs. rate of spread • Vehicles parked for escape Safety Zone(s) • Survivable without a fire shelter • Back into clean burn • Natural features (rock areas, water, meadows) • Constructed sites (clear-cuts, roads, helispots) • Scouted for size and hazards • Upslope? Downwind? Heavy Fuels? Each means more heat impact meaning larger safety zone. Time available to use escape routes will decrease and safety zone size will increase (possibly by more than double) as wind exceeds 10 mph and/or slope exceeds 20%! IRPG – Operational Engagement 7

Safety Zones A safety zone is an area where a firefighter can survive without a fire shelter. Considerations for effective safety zones: • Take advantage of heat barriers such as lee side of ridges, large rocks, or solid structures. • When possible, burn out safety zones prior to arrival of the fire front. • Avoid locations that are upslope or downwind from the fire; chimneys, saddles, or narrow canyons; and steep uphill escape routes. • Not intended for structure protection. Separation distance between the firefighter and the flames should be at least four times the maximum continuous flame height. Distance separation for flat terrain and no wind is the radius from the center of the safety zone to the nearest fuels. Flame Separation Distance Area in Height (firefighters to flames) acres* 10 ft. 40 ft. 1/10 acre 20 ft. 80 ft. ½ acre 50 ft. 200 ft. 3 acres 100 ft. 400 ft. 12 acres 200 ft. 800 ft. 46 acres *Area in acres is calculated to allow for distance separation on all sides for a 3-person engine crew (1 acre is approximately the size of a football field, or 208 feet by 208 feet). Calculations are based on radiant heat only and do not account for convective heat from wind and/or terrain influences. Since calculations assume no wind and no slope, safety zones downwind or upslope from the fire will require larger separation distances.

IRPG – Operational Engagement 8

Downhill Checklist Downhill fireline construction is hazardous in steep terrain, fast-burning fuels, or rapidly changing weather. It should not be attempted unless there is no tactical alternative. When building downhill fireline, the following is required: 1. Discuss assignments with crew supervisor(s) and fireline overhead prior to committing crew(s). Responsible overhead individual stays with job until completed (TFLD or ICT4 qualified or better). 2. Decision is made after proposed fireline has been scouted by supervisor(s) of involved crew(s). 3. Coordinate LCES for all personnel involved. • Crew supervisor(s) is in direct contact with lookout who can see the fire. • Establish communication between all crews. • Rapid access to safety zone(s) in case fire crosses below crew(s). 4. Use direct attack whenever possible. If not possible, the fireline should be completed between anchor points before being fired out. 5. Fireline will not lie in or adjacent to a chute or chimney. 6. Starting point will be anchored for crew(s) building fireline down from the top. 7. Monitor bottom of fire; if potential exists for the fire to spread, take action to secure the fire edge. IRPG – Operational Engagement 9

Indicators of Incident Complexity Common indicators may include the area (location) involved, political sensitivity, organizational complexity, jurisdictional boundaries, values at risk, weather, and threat to life, environment and property. Most indicators are common to all incidents, but some may be unique to a particular type of incident. The following are common contributing indicators for initial attack and extended attack complexity types. Type 5 Incident Complexity Indicators General Indicators Span of Control Indicators • Incident is typically terminated or concluded • Incident Commander (IC) (objective met) within a short time once position filled. resources arrive on scene. • Single resources are • For incidents managed for resource directly supervised by the objectives, minimal staffing/oversight is IC. required. • One to five single resources may be needed. • Command Staff or General • Formal Incident Planning Process not needed. Staff positions not needed • Written Incident Action Plan (IAP) not to reduce workload or span needed. of control. • Minimal effects to population immediately surrounding the incident. • Critical infrastructure, or key resources, not adversely affected.

Type 4 Incident Complexity Indicators General Indicators Span of Control Indicators • Incident objectives are typically met within • IC role filled. one operational period once resources arrive • Resources either directly on scene, but resources may remain on scene supervised by the IC or for multiple operational periods. supervised through an ICS • Multiple resources (over 6) may be needed. Leader position. • Resources may require limited logistical support. • Task Forces or Strike • Formal Incident Planning Process not needed. Teams may be used to • Written IAP not needed. reduce span of control to • Limited effects to population surrounding an acceptable level. incident. • Command Staff positions • Critical infrastructure or key resources may may be filled to reduce be adversely affected, but mitigation workload or span of measures are uncomplicated and can be control. implemented within one operational period. • General Staff positions • Elected and appointed governing officials, may be filled to reduce stakeholder groups, and political workload or span of organizations require little or no interaction. control.

IRPG – Operational Engagement 10

Type 3 Incident Complexity Indicators* Span of Control General Indicators Indicators • Incident typically extends into • IC role filled. multiple operational periods. • Numerous resources • Incident objectives usually not supervised met within the first or second indirectly through operational period. the establishment • Resources may need to remain at and expansion of scene for multiple operational the Operations periods, requiring logistical Section and its support. subordinate • Numerous kinds and types of positions. resources may be required. • Division • Formal Incident Planning Process Supervisors, Group is initiated and followed. Supervisors, Task • Written IAP needed for each Forces, and Strike operational period. Teams used to • Responders may range up to 200 reduce span of total personnel. control to an • Incident may require an incident acceptable level. base to provide support. • Command Staff • Population surrounding incident positions filled to affected. reduce workload or • Critical infrastructure or key span of control. resources may be adversely • General Staff affected and actions to mitigate positions filled to effects may extend into multiple reduce workload or operational periods. span of control. • Elected and appointed governing • ICS functional units officials, stakeholder groups, and may need to be political organizations require filled to reduce some level of interaction. workload. *If multiple Type 3 Incident Complexity Indicators are exceeded, consider the next level of incident management support.

IRPG – Operational Engagement 11

Wildland Urban Interface Firefighting Structure protection is inherently dangerous because it involves indirect firefighting. Do not commit to stay and protect a structure unless a safety zone for firefighters and equipment has been identified at the structure during sizeup and triage. Move to the nearest safety zone, let the fire front pass, and return as soon as conditions allow. Fire Behavior Prediction • Base all actions on current and expected fire behavior – do this first! • An estimate must be made of the approaching fire intensity in order to determine if there is an adequate safety zone and time available before the fire arrives. • Due to the dynamic nature of fire behavior, intensity estimates are difficult to make with absolute certainty. It is imperative that firefighters consider the worst case and build contingency actions into their plan to compensate for the unexpected.

IRPG – Operational Engagement 12

Structure Sizeup Site Considerations • Adequate safety zone based on fire behavior prediction. • Adequate lookout and communication capability. • Adequate defensible space based on surrounding wildland vegetation. • Avoid narrow canyon bottoms, mid-slope with fire below, and narrow ridges near chimneys and saddles. Tactical Challenges and Hazards (Firefighters with a safety zone can safely defend structures with some challenges.) • Narrow roads, unknown bridge limits, and septic tank locations. • Ornamental plants and combustible debris within 30 feet of structure. • Wooden siding and/or wooden roof materials. • Open vents, eaves, decks, and other ember traps. • Fuel tanks and hazardous materials. • Powerlines or underground utilities. • Limited water sources. • Prevailing sense of urgency. • Property owners remaining on-site or evacuations, which may cause panic. • Smoke byproducts often laced with chemical compounds not found in pure wildland fires.

IRPG – Operational Engagement 13

Structure Triage Defensible – Prep and Hold • Determining Factor: Safety zone present. • Sizeup: Structure has some tactical challenges. • Tactics: Firefighters needed on-site to implement structure protection tactics during fire front contact.

Defensible – Standalone • Determining Factor: Safety zone present. • Sizeup: Structure has very few tactical challenges. • Tactics: Firefighters may not need to be directly assigned to protect structure as it is not likely to ignite during initial fire front contact. However, no structure in the path of a wildfire is completely without need of protection. Patrol following the passage of the fire front will be needed to protect the structure.

IRPG – Operational Engagement 14

Non-Defensible – Prep and Leave • Determining Factor: NO safety zone present. • Sizeup: Structure has some tactical challenges. • Tactics: Firefighters not able to commit to stay and protect structure. If time allows, rapid mitigation measures may be performed. Set trigger point for safe retreat. Remember pre- incident preparation is the responsibility of the homeowner. Patrol following the passage of the fire front will be needed to protect the structure.

Non-Defensible – Rescue Drive-By • Determining Factor: NO safety zone present. • Sizeup: Structure has significant tactical challenges. • Tactics: Firefighters not able to commit to stay and protect structure. If time allows, check to ensure that people are not present in the threatened structure (especially children, elderly, and invalid). Set trigger point for safe retreat. Patrol following the passage of the fire front will be needed to protect the structure.

IRPG – Operational Engagement 15

Structure Protection Tactics Rapid mitigation measures • Remove small combustibles immediately next to structure. • Close windows and doors, including garage (leave unlocked). • Clean area around fuel tank and shut off tank. • Charge garden hoses. • Apply CAF, foam, or gel retardants if available. Equipment and water use • Mark entrance to indicate a staffed location if it is not obvious. • Charge hose lines. • Long hose lays are not recommended. • Keep 100 gallons of water in reserve. • Identify a backup water source. • Identify powerlines for aerial resources. • Never rely on water for firefighter safety. Patrol following the fire front • Many structures do not burn until after the fire front has passed. • Be aware of the structural collapse zone when structures are exposed to fire. • Move to closest safety zone and let fire front go through. • Return as soon as conditions allow safe access to structures. • Secondary ignition is usually due to residual spot fires or creeping ground fire. • Take suppression actions within your capability. • Call for assistance if needed.

IRPG – Operational Engagement 16

NOTES

IRPG – Operational Engagement 17

NOTES

IRPG – Operational Engagement 18

SPECIFIC HAZARDS – gray pages How to Properly Refuse Risk Every individual has the right and obligation to report safety problems and contribute ideas regarding their safety. Supervisors are expected to give these concerns and ideas serious consideration.

When an individual feels an assignment is unsafe they also have the obligation to identify, to the degree possible, safe alternatives for completing that assignment. Turning down an assignment is one possible outcome of managing risk.

A “turn down” is a situation where an individual has determined they cannot undertake an assignment as given and they are unable to negotiate an alternative solution.

The turn down of an assignment must be based on an assessment of risks and the ability of the individual or organization to control those risks. Individuals may turn down an assignment as unsafe when:

1. There is a violation of safe work practices. 2. Environmental conditions make the work unsafe. 3. They lack the necessary qualifications or experience. 4. Defective equipment is being used.

IRPG – Specific Hazards 19

• The individual directly informs their supervisor they are turning down the assignment as given. Use the criteria outline in the Risk Management Process (Firefighting Orders, Watch Out Situations, etc.) to document the turn down. • The supervisor notifies the Safety Officer immediately upon being informed of the turn down. If there is no Safety Officer, the appropriate Section Chief or the Incident Commander should be notified. This provides accountability for decisions and initiates communication of safety concerns within the incident organization. • If the supervisor asks another resource to perform the assignment, they are responsible to inform the new resource that the assignment was turned down and the reasons why it was turned down. • If an unresolved safety hazard exists or an unsafe act was committed, the individual should also document the turn down by submitting a SAFENET (ground hazard) or SAFECOM (aviation hazard) form in a timely manner. These actions do not stop an operation from being carried out. This protocol is integral to the effective management of risk as it provides timely identification of hazards to the chain of command, raises risk awareness for both leaders and subordinates, and promotes accountability.

IRPG – Specific Hazards 20

Thunderstorm Safety Approaching thunderstorms may be noted by a sudden reverse in wind direction, a noticeable rise in wind speed, and a sharp drop in temperature. Rain, hail, and lightning occur only in the mature stage of a thunderstorm. Situation Awareness: Sound waves move at different rates based on atmospheric conditions. Take the storm precautions below as soon as you hear thunder, not when the storm is upon you. Do not resume work in exposed areas until 30 minutes after storm activity has passed. Hazard Control: • Take shelter in a vehicle or building if possible. • If outdoors, find a low spot away from tall trees, wire fences, utility lines and other elevated conductive objects. Make sure the place you pick is not subject to flooding. • If in the woods, move to an area with shorter trees. • If only isolated trees are nearby, keep your distance twice the tree height. • If in open country, crouch low, with feet together, minimizing contact with the ground. You can use a pack to sit on, but never lie on the ground. • If you feel your skin tingle or your hair stand on end, immediately crouch low to the ground. Make yourself the smallest possible target and minimize your contact with the ground. • Don’t group together. • Don’t stay on ridge tops, in wide open areas, or near ledges or rock outcroppings. • Don’t operate landline telephones, machinery, or electric motors. • Don’t handle metal hand tools or flammable materials in open containers.

IRPG – Specific Hazards 21

Hazard Tree Safety Hazard trees, both dead snags and live green trees, are one of the most common risks encountered on the fireline. All firefighters should frequently survey their work area for potential hazard trees. Situation Awareness Environment: • Current and forecasted winds • Night operations • Steep slopes • Diseased or bug-kill areas • Number and height of hazard trees • Anticipated burn-down time • Potential for trees to domino Hazard tree indicators: • Trees burning for any period of time • High risk tree species (rot and shallow roots) • Numerous downed trees • Dead, broken, or burning tops and limbs overhead • Accumulation of downed limbs • Absence of needles, bark, or limbs • Leaning or hung-up trees

IRPG – Specific Hazards 22

Hazard Control • Eliminate the hazards with qualified sawyers, blasters/explosives, or heavy equipment. • Avoid hazards by designating “No Work Zones” (flag, sign, and map). • Modify suppression tactics or fireline location to avoid high risk areas. • Post lookouts to help secure high risk areas. • Utilize road/traffic controls in high risk areas. • Fire proof potential hazard trees to prevent ignition. • Keep clear of bucket drops near trees/snags. • Reposition firefighters to secure areas in response to high winds in forecast. • Provide timely feedback to others regarding any hazard trees. In addition to suppression and mop up operations, assess, control, and monitor hazard trees along roads and when selecting break areas or campsites.

IRPG – Specific Hazards 23

Powerline Safety Fire activity near high voltage electrical transmission/ distribution lines can cause multiple hazards and electrocute or seriously injure firefighters. The IC and line supervisors must be aware and communicate powerline hazards to all resources. Contact power companies when powerlines are threatened or involved. Down Powerlines • Communicate: Notify all responders of down electrical lines. Obtain radio check-back. • Identify: Determine entire extent of hazard by visually tracking all lines, two poles in each direction, from the downed wire. • Isolate: Flag area around down wire hazards; post guards. • Deny entry: Delay firefighting actions until hazard identification and flagging are complete and/or confine actions to safe areas. • Downed line on vehicle: Stay in vehicle until the power company arrives. If vehicle is on fire, jump out with both feet together. Do not touch the vehicle. Keep feet together and shuffle or hop away. • Always treat downed wires as energized! IRPG – Specific Hazards 24

Ground Tactics • Normal tactics apply when fire is more than 100 feet from powerlines. • Heavy smoke and flames can cause arcs to ground. Direct attack must be abandoned within 100 feet of transmission lines. • Spot fires or low ground fires can be fought with hose lines if heavy smoke or flame is not within 100 feet of powerlines. • Always maintain a distance of 35 feet from transmission towers. • Never use straight streams or foam—use a fog pattern. • Use extreme caution if engaging in tactical firing operations. • Extinguish wooden poles burning at the base to prevent down wire hazards. Aerial Tactics • Communicate locations of all transmission lines to air resources. • Aerial drops onto powerlines will cause arcing to ground or arcing to powerline towers and poles. • Drops should be parallel to lines and avoid drift making contact on the powerlines. • When flying across powerlines, cross at the towers. ALWAYS! • Look Out for any powerlines near the incident. • Communicate location of all powerlines that present a hazard. • Escape Routes should not be under or near overhead powerlines. • Safety Zones, ICP, and staging areas should not be located under or near overhead powerlines. IRPG – Specific Hazards 25

Roadside Response Safety • Anytime traffic flow is affected by the incident, contact the jurisdictional law enforcement agency for assistance.

• Conduct all operations as far from traffic lanes as possible. • When working in traffic and not involved in fire suppression activities, high visibility vests must be worn. • Park vehicles on the same side of the roadway. • Exit the vehicle away from the roadway whenever possible. • Post lookouts to watch for and control traffic in both directions. • Utilize road flares or other traffic warning signs. • Operate pumps from the non-traffic side or from the cab of the fire apparatus.

• Keep all hose, fire tools, and equipment out of traffic lanes.

IRPG – Specific Hazards 26

Unexploded Ordnance Safety Unexploded ordnance (UXO) is most likely to be encountered on military or former military sites. UXO poses risk of injury or death to anyone in the vicinity. Situation Awareness • Early identification of potential UXO is the first and most important step in reducing risk posed by UXO. • Many types of UXO may be encountered: Small arms munitions Projectiles Grenades Rockets Mortars Guided missiles Bombs Sub munitions • UXO may be found fully intact or in fragments. All UXO, whether intact or in fragments, presents a potential hazard and should be treated as such. • Deteriorated UXO presents a particular hazard because it may contain chemical agents that could become exposed. Hazard Control • If you see UXO, stop and do not move closer. • Isolate and clearly mark the area. • Deny entry to others. • Never transmit radio frequencies near UXO. • Never remove anything near UXO. • Never touch, move, or disturb UXO. • Keep a minimum of 1,000 feet away from areas on fire that contain suspected UXO. • Report discovery of UXO to your immediate supervisor. • U.S. Army Operations Center for incidents involving explosives and ammunition: (703) 697-0218. IRPG – Specific Hazards 27

Oil and Gas Site Safety When responding to an incident with oil and gas fields and/or coal seams, you must receive the appropriate training or a briefing before your operational assignment. Primary hazards include toxic gases as well as industry operations and facilities. Situation Awareness

Methane (CH4):

• Toxic, flammable, odorless, and colorless. • Unlikely to cause physical problems in open environment, but does pose a fire risk in high concentrations. • Beware of enclosed buildings/vehicles if gas is suspected.

Hydrogen Sulfide Gas (H2S) • Highly toxic, flammable, and colorless gas. • Odor of rotten eggs at low concentrations. • Sense of smell rapidly deteriorates at higher concentrations. • Exposure indicators include high heart rate, respiratory paralysis, seizures, and rapid incapacitation.

IRPG – Specific Hazards 28

Hazard Control • Ensure contact is made with the appropriate authorities before engaging in suppression activities.

• Ask for H2S monitor/breathing apparatus and adequate briefing. • Do not depend of sense of smell for warning.

• Avoid low lying areas during stagnant air conditions. • Anticipate industry traffic on narrow, unimproved roads.

• Be aware of exposed pipes and utility lines. • Park at least 20 feet away from facilities and equipment. Avoid tampering with the oil and gas pumping equipment.

• Avoid open pits/dumps. • Before starting dozer operations, ask your local dispatch to notify the appropriate utility representative. Don’t assume pipelines are buried deeply or directly under their markers. • Seek immediate medical care at a hospital if H2S exposure is suspected.

IRPG – Specific Hazards 29

Smoke Hazards and Mitigation 1. Line Personnel • Direct attack, line holding and mop up resources have the highest smoke exposures. Symptoms of over exposure start with headaches and visual impairment, then impaired decision making, and possible death (from carbon monoxide). If needed rotate resources in and out of smoky areas. Consider exposure when developing mop up standards. • Use lookouts to monitor and communicate hazardous smoke conditions that may impact nearby roads. Make appropriate supervisory and/or safety notifications. 2. ICP/Spike Camps • Avoid locating camps in valleys or lower lying areas where smoke can concentrate under potential inversion conditions, in drainages where smoke can flow through, or where the fire is adjacent to camp. 3. Public • Identify possible smoke sensitive areas (roads, communities, which can include schools and hospitals, etc.) that may be impacted by smoke. Monitor smoke impacts, and when heavy smoke is expected or present, notify authorities such as the air regulatory agency, health department, or public safety directly or through dispatch. IRPG – Specific Hazards 30

Smoke and Transportation Safety 1. Assess safety risks to personnel and public posed by smoke on roads. During initial attack and/or daily sizeup on extended attack, evaluate the potential of smoke to impact roadways up to three miles away. Identify drainages that may allow for smoke to impact roadways during the night and early morning. 2. Critical threshold values that identify potential for reduced visibility: - Surface Temperature ≤ 70 F

- RH ≥ 70 % ⁰ - Surface Wind Speed < 7 mph - Cloud Cover ≤ 60 % 3. Hazard Control: Mitigate when roadway visibility is expected to be impacted. Consider use of: smoke observers, smoke signs, reduced speed limit, drone car, lead car, lane closure, or, if necessary, entire road closure. Notify appropriate authorities. Consider use of local, regional, or national air resource or meteorological specialists (Air Resource Advisors (THSP), Incident Meteorologist (IMET)).

IRPG – Specific Hazards 31

Last Resort Survival Escape if you can. • Utilize all your PPE and act immediately on your best option. • Drop your gear to increase escape speed. Keep your fire shelter and, if time allows, your hand tool, water, and radio. • You may be able to use the fire shelter for a heat shield as you move. • In LIGHT FUELS, you may be able to move through the flames into the black. • If you are on the flank of the fire, try to get below the fire. • Consider vehicles or helicopters for escape. Find a survivable area. • Stay out of hazardous terrain features. • Use bodies of water. • In LIGHT FUELS, you may be able to light an escape fire. In other fuels, you may be able to light a backfire. • Call for helicopter or retardant drops. • Cut and scatter fuels if there is time. • Use any available heat barriers such as large rocks and dozer berms. • Consider vehicle traffic hazards on roads. • Structures and vehicles may be an option for temporary refuge.

IRPG – Specific Hazards 32

Pick a fire shelter deployment site. • Your first priority is to maximize distance from nearest surface fuels. • Find the lowest point available. • If possible, pick a surface that allows the fire shelter to seal and remove ground fuels. • Get into the fire shelter before the flame front hits. • Position your feet toward the fire and hold down the fire shelter. • Keep your face pressed into the ground and protect your airway. • Deploy next to each other and keep talking. Expect: • Extremely heavy ember showers. • Superheated air blast to hit before the flame front. • Noise and turbulent powerful winds hitting the fire shelter. • Heat and fire glow inside the fire shelter. • Long deployment times…WHEN IN DOUBT WAIT IT OUT. • Do not expect radio communication capabilities. • Do not expect water or retardant from aerial resources.

IRPG – Specific Hazards 33

NOTES

IRPG – Specific Hazards 34

ALL HAZARD RESPONSE – yellow pages Vehicle Accident Operations Report on Conditions • Hazards (fuel, electrical, traffic, access, etc.). • Need for law enforcement, ambulance, helicopter, tow truck, extrication tools. • Injuries (number of victims, severity). • Vehicles (number, type). Establish Traffic Control • Place apparatus between oncoming traffic and rescuers. Keep exhaust from pointing at scene and victims. • Place warning devices. • Establish positive communications. • Consider the use of high visibility vests. Assess Fire Hazard or Potential • Take suppression action as needed if trained, equipped and authorized. • Be aware of fuels running downgrade. Perform Patient Assessment • Provide first aid or triage assessment. • If there are fatalities, do not give names or other information over radio that would reveal identity, and do not move body. Keep dispatcher advised of changes. Document all actions taken. IRPG – All Hazard Response 35

HazMat Incident Operations Think Safety • Assess situation. • Safe approach: upwind/upgrade/upstream. • Identify, isolate, establish perimeter, and deny entry. • Notify agency dispatcher. • Exact location, use GPS. • Request needed assistance: identify a safe route. Scene Management • Goal is to protect life, environment and property. • Attempt to identify substance using 2112 Emergency Response Guide (use binoculars, placards/labels, container shapes/colors, Material Safety Data Sheets, shipping papers, or license plate). • Assess quantity of material involved. • Identify exposures and hazards surrounding the site. • Anticipate weather influences. Organizational Responsibilities • Establish command including an IC and Safety Officer. • Develop action plan for area security and evacuation. • Advise all on scene and responding resources of changes in situation. • Keep dispatcher advised of changes. • Document all actions taken. • Make special note of any responder exposures.

IRPG – All Hazard Response 36

HazMat Isolation Distances • Minor event (1 drum, 1 bag, etc.) = 150 feet • Major event (1 drum or more, etc.) = 500 feet • Residential and light commercial = 300 feet • Open areas = 1,000 feet • BLEVE (Boiling Liquid Expanding Vapor Explosion) potential = 2,500 feet (one-half mile) • Stage arriving units 2,500 feet upwind • Position vehicles headed out The following 24-hour emergency response communication services have agreed to provide immediate information about chemicals and/or assistance from a manufacturer: CHEMTREC 1-800-424-9300 CHEMTEL 1-800-255-3924 INFOTRAC 1-800-535-5053 3E COMPANY 1-800-451-8346 U.S. Army Operations Center for incidents involving explosives and ammunition: (703) 697-0218 24-hour emergency and information calls to the nearest Poison Center: 1-800-222-1222 Federal law requires that all spills of hazardous substances must be immediately reported to the U.S. Coast Guard/National Response Center: 1-800-424-8802

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HazMat Classification for Fixed Facilities Based on NFPA 704 HEALTH HAZARD FIRE HAZARD 4 Deadly 4 Below 73ºF 3 Extreme Danger 3 Below 100ºF 2 Hazardous 2 Above 100ºF not 1 Slightly Hazardous exceeding 200ºF 0 Normal Material 1 Above 200ºF 0 Will not burn

SPECIFIC HAZARD REACTIVITY ACID – Acid 4 May detonate ALK – Alkali 3 Shock and heat may COR – Corrosive detonate OX – Oxidizer 2 Violent chemical – Radioactive change W – Use no water 1 Unstable if heated SA – Simple asphyxiant 0 Stable POI – Poisonous IRPG – All Hazard Response 38

Local Disaster Response • Assess crew for injuries. • Move apparatus out of station if possible. • Determine if phones are working. • Check for power. • Assess the station for damage. • Monitor phone and radio for dispatch information. • Report by radio to dispatch or IC if established. • Initiate a “windshield survey” of first response area. • Do not fully commit to any incident. - Prioritize incidents with respect to life, hazard, and property. - Note any damage to infrastructure (roads, bridges, etc.). - Check for hazardous utility situations (gas, electric, water). - Note structural instability/collapse of any buildings. - Expect malfunctioning automatic alarms. - Use “negative reporting.” Only report things out of the ordinary. • Follow local disaster plans.

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All Hazard Incident Response Wildland firefighters often respond to large scale disasters that can cover extensive geographic areas and impact many people. Often times these impacts are to large urban centers. Typical assignment tasks include search and rescue, debris clearing, and distribution of basic necessities. When responding, consider that basic services, utilities, transportation, medical care, credit card/ATM capability and law enforcement and security will likely be disrupted. Be considerate of those impacted by the disaster. • Plan to be self-sufficient for 24 to 48 hours. • Bring a GPS unit if possible. • Be prepared for extreme weather conditions associated with storm disasters. • Establish central rally points for assigned responders. • Develop local contacts for information gathering. • Dust and debris may interfere with respiration and visibility. • Weakened structures, fires, leaking hazardous materials, raw sewage contamination, and waterborne diseases may pose additional risks. • Mobility and access may be impaired by critical infrastructure damage, disrupted utilities, structural collapse, flooding, ice covered roads, or other barriers. • In the case of natural disasters, be aware of the additional threats following the initial storm or earthquake.

IRPG – All Hazard Response 40

Structure Hazard Marking System Never enter a damaged structure unless trained, equipped, and authorized. You may find a 2' x 2' box at the entrance to indicate the condition of the structure. Use orange spray paint or a lumber crayon to mark inside the box.  Structure is safe for Search and Rescue (SAR) with minor damage, or structure is fully collapsed. ⁄ Structure is significantly damaged with some safe areas but other areas which need to be shored up or braced. Falling and collapse hazards need to be removed.  Structure is unsafe and may collapse suddenly.  Entrance is located in direction of the arrow. HM Hazardous material is present. This information should be found outside the upper right portion of the box: • Specialist ID • Time and date of assessment • Hazardous materials identified SAR teams should also mark structures as they conduct operations. ⁄ Single slash (2' long) indicates SAR Team is currently in structure conducting operations. × Cross/slash (2' x 2') indicates SAR Team has left structure/area. This information should be found in the four quadrants of the cross slash: • SAR Team ID Left quadrant • Time and date team left structure Upper quadrant • Personnel hazards Right quadrant • Number of victims still inside Lower quadrant structure (“X” indicates no victims remaining) IRPG – All Hazard Response 41

Missing Person Search Urgency Factor AGE Rating Very young Very old 1 Other 1 MEDICAL CONDITION 2-3 Known/suspected injured, ill or mental problem Healthy 1-2 Know Fatality 3 NUMBER OF SUBJECTS 3 One alone More than one (unless separated) 1 SUBJECT EXPERIENCE PROFILE 2-3 Inexperienced, does not know area Not experienced, knows area 1 Experienced, not familiar with area 1-2 Experienced, knows area 2 WEATHER PROFILE 3 Past and/or existing hazardous weather Predicted hazardous weather (less than 8 hours away) 1 Predicted hazardous weather (more than 8 hours away) 1-2 No hazardous weather predicted 2 EQUIPMENT PROFILE 3 Inadequate for environment and weather Questionable for environment and weather 1 Adequate for environment and weather 1-2 TERRAIN/HAZARDS PROFILE 3 Known terrain or other hazards Few or no hazards 1 TOTAL 2-3

(Range = 7-21, with 7 the highest urgency and 21 the lowest urgency)

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NOTES

IRPG – All Hazard Response 43

NOTES

IRPG – All Hazard Response 44

AVIATION – bl ue pages Aviation User Checklist

• Pilot/ Aircraft Data Card—Approved and current for aircraft type, contract and mission?

• Flight Plan/Flight Following—Initiated and confirmed with agency/bureau? • PPE —available and worn by all passengers and pilot as required for the mission?

• Pilot briefed on mission objectives, flight route, known flight hazards, and aerial hazard map? • Pilot or flight manager safety briefing provided to passengers? To include: - Aircraft hazards - Seatbelt or harness - Fuel and electrical shutoff - ELT and survival kit - Oxygen (if applicable) - First aid kit - Gear and cargo storage - Emergency seating position - Emergency exit(s) - Fire extinguisher - No smoking

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Aviation Watch Out Situations • Is this flight necessary? • Who is in charge? • Are all hazards identified and have you made them known? • Should you stop the operation or flight due to change in conditions? − Communications − Weather − Confusion − Turbulence − Conflicting Priorities − Personnel • Is there a better way to do it? • Are you driven by an overwhelming sense of urgency? • Can you justify your actions? • Are there other aircraft in the area? • Do you have an escape route? • Are any rules being broken? • Are communications getting tense? • Are you deviating from the assigned operation or flight? Anyone can refuse or curtail a flight when an unsafe condition may exist. Never let undue pressure (expressed or implied) influence your judgment or decisions. Avoid mistakes; don’t hurry! IRPG – Aviation 46

Helicopter Passenger Briefing and PPE Pilot or designated helitack must brief all passengers prior to flight. Personal Protective Equipment (PPE) • Flame resistant clothing (long-sleeved shirt and pants, or flight suit). • Approved helicopter flight helmet, or hardhats for fire crew transport from managed sites. • All-leather boots. • Hearing protection. • Eye protection. • Flame resistant or leather gloves. Approach and Departure • Stay clear of landing area during approach/ departure. • Always approach/depart from the downslope (lower) side as directed by pilot/ helitack. • Approach/ depart helicopter in a crouch position. • Do not run. • Keep in pilot’s view at all times. • Do not reach up or chase after loose objects. • Never approach the tail section of the helicopter. • NO SMOKING within 50 feet of the aircraft.

IRPG – Aviation 47

Tools and Equipment • Secure light/loose items awaiting transport. • Assign personnel for carrying tools and equipment to and from helicopter. • Carry tools and long objects parallel to the ground, never on shoulder. • All tools and equipment loaded/unloaded by qualified personnel. • Portable radios turned off. Helicopter Doors • Location and how to operate. In-Flight Discipline • Follow pilot instructions. • Loose items inside of aircraft secured and manageable. • All baggage secured in aircraft or cargo compartment. • No movement inside aircraft once seated. • Never throw objects from the helicopter. • Keep clear of the flight controls at all times. • Unbuckle only when directed to do so by pilot or helitack. • Wait for helitack personnel to open/close doors. • Know location of first aid kit, survival kit, fire extinguisher, ELT (emergency locator transmitter), fuel and battery shutoff switch location and operation, radio operation.

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In-Flight Emergency Procedures • Emergency exit location and how to operate. • Follow instructions of pilot/ helitack personnel. • Snug seat belt and shoulder harness (know how to operate); secure gear. • Emergency Seating Positions: - Forward Facing Seat: o Press your lower torso firmly against the seat back. o Lower your chin to chest. Grip the seat edge with your hands or place them under your legs. o Do not grasp the restraint harness. - Rear Facing Seat: o Same as Forward Facing Seat except, place your head back against the head rest or bulkhead. - Side Facing Seat: o Lean toward the front of the aircraft and brace your upper torso and head against whatever might be contacted, or move the head in the direction of impact to reduce flailing. • Move clear of the aircraft only after rotor blades stop or when instructed by the pilot or helicopter crew. • Assist injured personnel. • Assess situation, remove first aid kit, survival kit, radio, ELT, and fire extinguisher. Render first aid. Attempt to establish contact.

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Helicopter Landing Area Selection Choosing a Landing Area • Locate a reasonably flat area clear of people, vehicles, and obstructions such as trees, poles, and overhead wires. • The area must be free of stumps, brush, posts, large rocks, and anything over 18 inches high. • Consider the wind direction. Helicopters land and take off into the wind. Choose an approach free of obstructions. • Any obstruction should be relayed to the helicopter crew on initial radio contact. • Remove or secure any loose items in and around the landing area such as trash, blankets, hats, or equipment. • Wet down the landing area if dusty conditions are present. • Address LCES prior to staffing existing or proposed helicopter landing areas. Fixed Helispots • Type I Helicopters: - Safety circle: 110′ - Touchdown pad: 30′ x 30′, clear and level • Type II Helicopters: - Safety circle: 90′ - Touchdown pad: 20′ x 20′, clear and level • Type III Helicopters: - Safety circle: 75′ - Touchdown Pad: 15′ x 15′ clear and level Items Needed • 40 BC fire extinguisher (20 lb.) • Wind Indicator • Radio (compatible with helicopter) • Pad marker • Allowable payloads (HIGE & HOGE) for all helicopters using helispot • Passenger/cargo manifest book • Dust abatement, as needed IRPG – Aviation 50

One-Way Helispot

IRPG – Aviation 51

Two-Way Helispot

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Longline Mission • All individuals involved in longline missions will have been trained in longline operations. • If you are on the receiving end or backhaul end of a longline load, you must be able to communicate to the pilot where you want the load delivered or picked up. • Use a signal mirror to identify your position to the pilot. • The drop-off/pick-up area should be as open and free of obstacles as possible. • Once you have contacted the pilot by radio, provide specific load and site information (cargo weight, any hazardous materials, wind speed and direction, etc.). • Mark the drop-off spot with flagging (large “X” on the ground) if possible. • Keep pilot informed of load status (height above the ground, clear of obstacles, etc.). • Let the hook land on the ground before attaching load. • If the electrical release does not release the load, you must manually release it; wait until the hook lands on the ground before releasing. • For ALL backhaul, a “swivel” must be connected to the cargo/longline hook. NO EXCEPTIONS! (When you request nets, request swivels also.) • Load cargo net with heavy items in the center, light items on top. Tape all boxes and loose items. • Pull the “purse strings” of the cargo net to equal length and attach a swivel to the steel rings. It’s not necessary to “cross” the purse strings with an overhand wrap. IRPG – Aviation 53

Helicopter Hand Signals

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Paracargo Operations Safety • Mark the target area with a large “X” using visible flagging in an open or cleared area. • The drop site should be roughly an acre in size, depending on terrain and vegetation. Most helispots, ridge tops, and meadows work well. • Camps should be at least 600' from target area. • All persons, vehicles, and animals should be cleared from the drop site prior to arrival of the cargo aircraft. • An individual should be in charge at drop site. • The individual in charge should relay the following information to the cargo aircraft: - Confirm drop location. - Winds at ground level. - Any specific hazards in the area. - Individuals on the ground are clear and ready to receive cargo. • The individual in charge should alert all personnel around the drop site that cargo operations are about to begin. • All personnel in the vicinity should be “heads up” in the rare event that a parachute doesn’t open. • All personnel should remain clear of the drop site until paracargo operations are complete. • Treat cargo parachutes with care and return them to their respective bases at the earliest convenience.

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Weight Estimates (use only if scale is not available) Item Weight Backpack pump (full) 45 lbs. Cargo net 12’x12’ 20 lbs. Cargo net 20’x20’ 45 lbs. Cargo net (fish net) 5 lbs. Cargo hook (1 hook) 35 lbs. Jerry can/fuel (5 gal.) 45 lbs. Canteen (1 gal.) 10 lbs. Dolmar (full) 15 lbs. Drip torch (full) 15 lbs. Fusee (1 case) 36 lbs. Hand tool (each) 8 lbs. Lead line (12 ft.) 10 lbs. Long line (50 ft.) 30 lbs. Swivel 5 lbs. Chain saw 25 lbs. Hose, 1½" syn. 100' 23 lbs. Hose, 1" syn. 100' 11 lbs. Hose, 3/4" syn. (1,000'/case) 30 lbs. Hose, suction, 8 ft. 10 lbs. Mark 3 – Pump w/kit 150 lbs. Stokes w/ backboard 40 lbs. Trauma bag 35 lbs. MRE, 1 case 25 lbs. Cubee/water (5 gal.) 45 lbs.

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Aerial Retardant Safety Clear personnel out of target area prior to drops. If you can’t escape: • Hold your hand tool away from your body. • Lie face down with head toward oncoming aircraft and hardhat in place. Grasp something firm to prevent being carried or rolled about by the dropped liquid. • Do not run unless escape is assured. • Get clear of dead snags, tops, and limbs in drop area. • Working in an area covered by wet retardant should be done with caution due to slippery surfaces.

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Directing Retardant and Bucket Drops • Give general location on incident to aerial resource– division/head/heel/flank. • Identify any flight hazards to the ATGS, ASM/LP, airtanker pilot or helicopter pilot. • Finalize location with: - Clock position from pilot’s perspective (see IRPG front cover). - Description of prominent landmarks. - Target position on slope – lower 1/3, upper 1/3, mid-slope, top of ridge, etc. - Utilize signal mirrors whenever possible. - Utilize panels or flagging to mark target as needed. • Describe target from your location and explain mission. The pilot will decide drop technique and flight path. • Know the pilot’s intentions prior to the drop. Clear the area to avoid direct flights over ground personnel and equipment. • Give feedback to pilot about drop accuracy. Be honest and constructive. Let pilot know if drop is early, late, uphill, downhill, on target, too high, too low, etc. Report low drops immediately. IRPG – Aviation 58

Principles for Airtanker and Water Scooper Use • Determine tactics, direct or indirect, based on fire sizeup and resources available. • Discuss strategy, tactics, wind conditions, and hazards with ATGS, ASM/LP, or airtanker pilot. - Establish a clear, obtainable objective for retardant use with aerial supervision. • Maintain effective communication with ATGS, ASM, or airtanker pilot. • Establish an anchor point and work from it. • Order appropriate aircraft for mission based on objectives, terrain and supporting ground resource tactics. • Use the appropriate coverage levels for the fuel type. See chart on page 61. • Drop downhill, into the wind and away from the sun if possible. • Order airtankers early; aircraft are most effective during initial attack and early and late in the day. • Let ground resources know when there is an airtanker inbound. • Ensure approach, departure, and line is clear of personnel and equipment. • Inform ATGS, ASM/LP, or pilot when the area drop area is clear. • Let ground resources know when drops are completed. • Get feedback from on-scene ground resources regarding drop effectiveness. • Relay feedback to aerial resource(s).

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Retardant and Suppressant Use Reminders • Suppressant (water, foam or water enhancer) = Direct attack with close ground support. • Retardant = Indirect attack, point protection and direct attack ahead of ground support. • Retardant use should coincide with ground support within 24 hours. Minimum Drop Heights for Airtankers and Water Scoopers

- SEAT/Amphibious SEAT = Min. 60 ft. (optimum 90 ft.) above the vegetation - LAT = 150 ft. above the vegetation - VLAT = 200 ft. above the vegetation - Water Scooper (CL 215/415) = 150 ft. above the vegetation ATGS = Air Tactical Group Supervisor ASM/LP = Aerial Supervision Module/ Lead plane Type 3 Airtanker = 800-1,799 gallons (S-2T, SEAT) Type 2 Airtanker = 1,800-2,999 gallons (Convair 580, Q- 400) Type 1 or Large Airtanker (LAT) = 3,000-5,000 gallons (BAe-146, RJ85, MD87, C-130) VLAT = Very Large Airtanker = >8,000 gallons (DC10, 747)

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Recommended Retardant Coverage Levels Coverage Fuel Model Description Level CL1 Short/Medium grasses and tundra

CL2 Conifer with grass Shortneedle closed conifer; summer hardwood Longneedle conifer; fall hardwood

CL3 Sagebrush with grass Sawgrass and tall grass Intermediate brush (green) Light Slash

CL4 Shortneedle conifer (heavy dead litter)

CL6 Southern Rough Intermediate brush (cured); Alaska Black Spruce

>CL6 California mixed chaparral; high pocosin Medium to heavy slash

IRPG – Aviation 61

Aircraft Mishap Response Actions Time is extremely critical when responding to an emergency. Immediate positive action is necessary; delay may effect someone’s survival. Rescue Operations • Preserve life. • Do whatever is necessary to extricate injured occupants and to extinguish fires. • Secure the area. • Document and/or photograph the location of any debris that must be disturbed in order to carry out rescue and/or fire suppression activities. • Identify witnesses and get contact information.

Site Safety Precaution Aircraft wreckage sites can be hazardous for many reasons other than adverse terrain or climatic conditions. Personnel involved in the recovery, examination, and documentation of wreckage may be exposed to physical hazards such as hazardous cargo, flammable and toxic fluids, sharp or heavy objects, and disease. It’s important to exercise good judgment, use available protective devices and clothing, and use extreme caution when working in the wreckage.

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SAFECOM Reporting System The purpose of the SAFECOM system is for accident prevention. It is a tool used to encourage the reporting of any condition, observance, act, maintenance problem, or circumstance that has the potential to cause an aviation or aviation-related accident. It can also be used for reporting positive safety actions and mishap prevention measures. Submitting a SAFECOM is not a substitute for on-the- spot correction(s) to a safety concern. While it is imperative that problems and issues be addressed at the local level, it is beneficial to share problems and solutions system wide. The SAFECOM system is not intended for initiating punitive actions. SAFECOM managers are responsible for protecting personal data and sanitizing SAFECOMs prior to posting to the public. Submit SAFECOMs online at https://www.safecom.gov/. FAX hard copies to OAS 208-433-5007 or USFS 208- 387-5735. Report any interagency aircraft mishap to 888-464-7427 (888-4MISHAP).

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NOTES

IRPG – Aviation 64

OTHER R EFER ENC ES – white pages Spot Weather Forecast Spot weather forecasts should always be requested for fires that have the potential for active fire behavior, exceed initial attack, or are located in areas where Red Flag Warnings have been issued. In addition, personnel should consider requesting a spot weather forecast for non-fire incidents including HazMat or search and rescue activities. The basic elements needed for a spot weather request include: • Location by street address/zip code/city name, latitude/longitude, US National Grid, or drag to a location using the spot forecast request webpage https://www.weather.gov/spot/ • Type of incident (wildfire, prescribed burn, HazMat, SAR) • Project/Incident Name • Requesting Agency/Official, email address and phone number • Elevation (at top and bottom of incident) • Drainage name, size, aspect, fuel type and sheltering (full, partial, unsheltered) • Forecast delivery time (i.e. as soon as possible or a later time), time forecast should start, and time zone • Any remarks that can help meteorologists forecast the site, pertinent feedback information (i.e. humidity values were lower than predicted), or special requests (i.e. very interested in potential wind shifts)

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Weather observations need to include: • Site location on the fire • Date of observation • Time of observation • Elevation • Wind direction • Wind speed • Dry bulb temp • Wet bulb temp • RH • Dewpoint temp (Td) • Sky cover • Weather (Wx) • Any special remarks for the observation time which could include fire behavior or describe wind/weather changes It is important weather feedback is provided to meteorologists who are completing the spot forecast request, either during or soon after the operational period is completed. If conditions on the ground do not match the forecast for a period of time you should request an updated or new spot forecast. Weather feedback can be provided several ways including: • Feedback text box found at the bottom of the spot forecast webpage for each specific incident. • Remarks/weather observation boxes prior to submitting a new request. • Fax fireline observations to local NWS office or call to relay the information.

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Weather Watch/Weather Warning A Watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still uncertain. A Warning is issued when a hazardous weather or hydrologic event is occurring, is imminent, or has a very high probability of occurring. A warning is used for conditions posing a threat to life or property.

Energy Release Component (ERC) The ERC serves as a good characterization of local seasonal fire danger trends resulting from the area’s fuel moisture conditions. The ERC is a relative index and should be compared to historic trends and thresholds on the corresponding area’s pocket card. The ERC relies heavily on large and live fuels, has low variability, and is not affected by wind speed.

Burning Index (BI) The BI reflects the changes in fine fuel moisture content and wind speed and is highly variable day-today. The BI is more appropriate for short-term fire danger and can be loosely associated with flame length by dividing the BI by 10. The BI is readily affected by wind speed and fine fuel moisture.

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Haines Index (HI) The HI is used to indicate the potential for rapid fire growth due to dry and unstable atmospheric conditions over a fire area. The index is a simple way to measure the atmosphere's contribution to the fire’s growth potential. A high Haines Index is correlated with large fire growth where winds do not dominate fire behavior. Index Fire’s Growth Potential 2 Very Low Potential (Moist and stable lower atmosphere) 3 Very Low Potential 4 Low Potential 5 Moderate Potential 6 High Potential (Dry and unstable lower atmosphere) Keetch-Byram Drought Index (KBDI) The KBDI is a daily value representative of the water balance where yesterday’s drought index is balanced with today’s drought factor (precipitation and soil moisture). The drought index ranges from 0 to 800; an index of 0 represents no moisture depletion and an index of 800 represents absolutely dry conditions. Index KBDI Indicators 0-200 Soil and large class fuel moistures are high. Most fuels will not readily ignite or burn. 200-400 Lower litter and duff layers are drying and beginning to contribute to fire intensity. Heavier fuels will still not readily ignite and burn. 400-600 Lower litter and duff layers actively contribute to fire intensity and will burn actively. Expect complete consumption of all but the largest fuels. Drying of soil will lower live fuel moistures allowing live fuels to become available to burn. 600-800 Often associated with severe drought and increased wildfire occurrence. Expect intense deep burning fires with significant spotting problems. Live fuels will burn actively at these levels and expect fires to be difficult to contain and control.

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Lightning Activity Level (LAL) Level LAL Indicators LAL 1 • No thunderstorms LAL 2 • Isolated thunderstorms. • Light rain occasionally reaches the ground. • Lightning very infrequent. • 1-5 strikes in 5 minutes. LAL 3 • Widely scattered thunderstorms. • Light to moderate rain will reach the ground. • Lightning is infrequent. • 6-10 strikes in 5 minutes. LAL 4 • Scattered thunderstorms. • Moderate rain is commonly produced. • Lightning is frequent. • 11-15 strikes in 5 minutes. LAL 5 • Numerous thunderstorms. • Rainfall is moderate to heavy. • Lightning is frequent and intense. • More than 15 strikes in 5 minutes. LAL 6 • Widely scattered dry thunderstorms. • No rain reaches the ground. • Lightning is infrequent. • May constitute the issuance of a Red Flag Warning.

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Important Winds to Firefighters

Typical Wind Wind Type Notes Speed Ranges Critical Winds Thunderstorm 25-35 mph can Gusty/erratic in (a.k.a. outflow exceed 60 mph nature. Blow and downdraft) from the direction of the thunderstorm. Frontal 20-30 mph can Also note shift exceed 50 mph in wind direction with frontal passage. Foehn Winds 20-60 mph can Warming and (Chinook, exceed 90 mph drying winds Santa Ana, blowing from Mono, high elevation Wasatch, East, to low and North) elevation. Surfacing or 25-45 mph Generally occur low level jets 100’s of feet above the ground. Can enhance fire plume. Whirlwinds 50+ mph Dust devils and fire whirls. Glacier 30-50 mph Occur down slope from glaciers. IRPG – Other References 70

Typical Wind Wind Type Notes Speed Ranges Local Winds Upslope 3-8 mph Late morning into early afternoon. Up-valley 10-15 mph Mid- to late afternoon. Downslope 2-5 mph Late evening through midnight. Downvalley 5-10 mph Late night into very early morning. Sea Breeze 10-20 mph Daytime: can exceed 30 Blows from mph the sea toward the land. Land Breeze 3-10 mph Nighttime: Blows from the land toward the sea. Source: S-290, Intermediate Fire Behavior

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Beaufort Scale FOR ESTIMATING 20-FT WIND SPEED Wind Wind Speed Nomenclature Class (mph) 1 <3 Very light – smoke rises nearly vertically. Leaves of quaking aspen in constant motion; small branches sway; slender branches and twigs of trees move gently; tall grasses and weeds sway and bend with wind; wind vane barely moves. 2 4-7 Light – trees of pole size in the open sway gently; wind felt distinctly on face; loose scraps of paper move; wind flutters small flag. 3 8-12 Gentle breeze – trees of pole size in the open sway very noticeably; large branches of pole size trees in the open toss; tops of trees in dense stands sway; wind extends small flag; a few crested waves form on lakes. 4 13-18 Moderate breeze – trees of pole size in the open sway violently; whole trees in dense stands sway noticeable; dust is raised on the road. 5 19-24 Fresh – branchlets are broken from trees; inconvenience is felt in walking against wind. 6 25-31 Strong – tree damage increases with occasional breaking of exposed tops and branches; progress impeded when walking against wind; light structural damage to buildings. 7 32-38 Moderate gale – severe damage to tree tops; very difficult to walk into wind; significant structural damage occurs. 8 >39 Fresh gale – surfaced strong Santa Ana; intense stress on all exposed objects, vegetation, buildings; canopy offers virtually no protection; wind flow is systematic in disturbing everything in its path. Source: Fire Behavior Field Reference, PMS 437

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Alignments and Patterns for Dangerous Fire Behavior Drought o Short-term or “Flash” • “snap-crackle-pop” - Do sticks snap with ease? - Does the timber litter crackle while you walk? - Do the leaves pop back in place after being crumpled? • Dust in the duff • ERC values at the 90th percentile or greater o Long term • Mortality-red needles Hot-Dry-Unstable Days o Plenty of sun during the morning o Temperatures above normal o Critically low humidity determined by regional climatology o High mixing heights o Haines Index values that are unusually high for the region. Inversion Breaks o Timing can vary based on terrain type, seasonality, latitude and day-to-day weather pattern changes o Quick jump in temperature, lowering humidity, and increased wind Windy-Dry-Unstable Days o Wide gust spreads (difference between gusts and sustained wind) • Difference range: 15 to 20 mph (battling-shifting wind) o Mostly sunny/high mixing heights/above normal surface temperatures

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o Leading edge of cold frontal passages o Low humidity for the area Thunderstorms (outflows/microbursts/gust fronts) o Cloud to ground lightning from fast moving and/or drier storms o Outflow boundaries that significantly raise wind speeds during hot-dry-unstable days o Outflow boundaries that quickly alter wind direction by 90 to 180 degrees Foehn/Downslope and Mountain Wave Events o Sudden bursts of wind especially during overnight hours that can lead to accelerated down slope/down canyon fire spread o Reversal of normal day/night (diurnal) wind flows o Rapid warming/drying Firefighters are encouraged to review and understand atmospheric patterns that lead to these critical weather alignments. They include:

o Cold frontal passages o Break-down of the upper level ridge o Monsoon bursts o Thermal lows/troughs o Mid-level dry intrusions/slots o Migrating surface dry line o Upper and low level jets o Subsidence-windy sector of Tropical Storms o Foehn downslope wind events (i.e. Santa Ana and Chinook) Consult National Weather Service and GACC Predictive Service meteorologists if there are any questions about the predicted patterns.

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Fire Behavior Hauling Chart Tactical Interpretations from Flame Length

Flame Length Interpretations Fires can generally be attacked at the head or flanks by firefighters Less than 4 feet using hand tools. Handline should hold fire. Fires are too intense for direct attack on the head with hand tools. Handline cannot be relied 4 to 8 feet on to hold the fire. Dozers, tractor-plows, engines, and retardant drops can be effective. Fire may present serious control problems: torching, crowning, 8 to 11 feet and spotting. Control efforts at the head will probably be ineffective. Crowning, spotting, and major fire runs are probable. Control Over 11 feet efforts at the head of the fire are ineffective.

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Relative Humidity: 1,400-4,999’ Elevation

IRPG – Other References 76

Relative Humidity: 5,000-9,200’ Elevation

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Probability of Ignition Tables 1. Using Table A, determine Reference Fuel Moisture (RFM) % from intersection of temperature and relative humidity. Record this RFM percentage. 2. Select Table B, C, or D to adjust RFM for local conditions by finding current month in table title. • Are the fine fuels more than 50% shaded by canopies and clouds? If yes, use bottom (shaded) portion of table. If no, use top (exposed) portion of table. • Determine the appropriate row based on aspect and slope. Determine the appropriate column based on time of day and elevation of area of concern when compared to the weather site elevation. • Obtain the Dead Fuel Moisture Content Correction (%) from the intersection of row and column. 3. Add the resulting Dead Fuel Moisture Content Correction (%) to the Reference Fuel Moisture (%).

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IRPG – Other References 80

IRPG – Other References 81

Strategy – Direct Attack Advantages: • Minimal area is burned; no additional area is intentionally burned. • Safest place to work; firefighters can usually escape into the burned area. • The uncertainties of firing operations can be reduced/eliminated. Disadvantages: • Firefighters can be hampered by heat, smoke, and flames. • Control lines can be very long and irregular. • Burning material can easily spread across mid-slope lines. • May not be able to use natural or existing barriers. • More mop up and patrol is usually required.

IRPG – Other References 82

Strategy – Indirect Attack Advantages: • Control lines can be located using favorable topography. • Natural or existing barriers can be used. • Firefighters may not have to work in smoke and heat. • Control lines can be constructed in lighter fuels. • There may be less danger of slopovers. Disadvantages: • More area will be burned. • Must be able to trade time and space for line to be constructed and fired. • Firefighters may be in more danger because they are distant from the fire and have unburned fuels between them and the fire. • There may be some dangers related to firing operations. • Firing operations may leave unburned islands of fuel. • May not be able to use control line already built.

IRPG – Other References 83

Fireline Location • The first consideration of line location is firefighter safety. • Whenever possible, use direct attack and build line as close to fire edge as conditions safely permit. • If indirect attack is required, locate line an adequate distance from the main fire so it can be completed, fired, and held considering the predicted rate of spread of the main fire. • Allow adequate time to permit forces to complete the line and conduct any firing operations in advance of severe burning conditions. • Make the line as short and straight as practical, using topography to your advantage. • Use easiest routes, taking advantage of light fuels, without sacrificing holding capability or significant resource values. • Use existing natural and human-made barriers. • Eliminate potential hazards from the fireline area whenever possible. If hazards must be left in the fire area, locate line a safe distance away. • Avoid undercut and mid-slope line in steep terrain. • Avoid sharp turns in the line. • Encircle area where spot fires are so numerous that they are impractical to handle as individual fires, then burn out the unburned fuels. • Lines that run along ridges should be located on the ridgetop or slightly to the lee side away from the main fire. • Use the Downhill Checklist (pg. 9) when considering building downhill line in steep terrain.

IRPG – Other References 84

Procedural Felling Operations Assess the situation, complete a hazard analysis, and establish cutting area control. Situation Awareness • Evaluate tree characteristics • Determine soundness or defects • Analyze the tree base • Check surrounding terrain • Examine work area Hazard Assessment • Overhead hazards • Ground hazards • Environmental hazards • Mental/physical hazards Felling Operation Controls • Use a lookout to help control felling area • Check for nearby hazard trees (domino effect) • Assess lean(s) and lay • Swamp out base and escape route • Brief swamper (role/responsibility) • Face tree with adequate undercut • Give warning yell • Maintain holding wood and stump shot • Frequently look up while cutting • Use proper wedging procedure • Use established escape route • Analyze stump for lessons learned IRPG – Other References 85

Working with Heavy Equipment • When working around heavy equipment stay at least 100 feet in front and 50 feet behind the equipment. In timber, distances should be increased to 2½ times the canopy height. • No one but the operator should ride on the equipment. • Never approach equipment until you have eye contact with the operator, all implements have been lowered to the ground, and equipment is idled down. • Avoid working downhill from equipment where rolling material could jeopardize your safety.

• Night work is more dangerous due to reduced visibility. Use headlamp and/or glow sticks so the operator can see you. • Establish visual and radio communication methods prior to engaging. • Communicate all hazards to the operator (spot fires, firing operations, and obstacles). • Equipment operators have difficulty seeing ground personnel; take responsibility for your safety and all those around you.

IRPG – Other References 86

Water Delivery Information • Pump Discharge Pressure (PDP) = Nozzle Pressure (NP) + Friction Loss (FL) of Hoselay ± Head Pressure (HP) • Gallons per Minute (GPM) and NP: Forester 3/16 tip: 7 gpm (50 psi NP) 3/8 tip: 30 gpm (50 psi NP) Variable Pattern (Adjustable Barrel) 1 inch: 20 gpm (100 psi NP) 1½ inch: 60 gpm (100 psi NP) • FL for 1" hose: 10 gpm = 5* psi per 100’ 20 gpm = 10 psi per 100’ 30 gpm = 20* psi per 100’ • FL for 1½" hose: 20 gpm = 1 psi per 100’ 30 gpm = 5* psi per 100’ 60 gpm = 15* psi per 100’ * Numbers rounded for easier math • HP: Add or subtract 1 psi for every 2’ elevation change. • Gallons of water to fill 100’ of hose: ¾" hose ≈ 2 gals. 1" hose ≈ 4 gals. 1½" hose ≈ 9 gals. • Maximum effective lift for drafting = 22’ at sea level, 14’ at 8,000’ elevation. • Loss of 1’ draft per 1,000’ elevation. • Use check and bleeder valve on pump discharge when pumping uphill to prevent back flow into the pump. • A parallel hose lay will have ¼ the friction loss of a single hose lay. IRPG – Other References 87

Engine ICS Typing

Engine Type Structure Wildland Requirements 1 2 3 4 5 6 7 Tank minimum capacity (gal) 300 300 500 750 400 150 50

Pump minimum flow (gpm) 1,000 500 150 50 50 50 10

@ rated pressure (psi) 150 150 250 100 100 100 100 Hose 2½" 1,200 1,000 – – – – – 1½" 500 500 1,000 300 300 300 – 1" – – 500 300 300 300 200 Ladders per NFPA 1901 Yes Yes – – – – – Master stream 500 (gpm) Yes – – – – – –

Pump and roll – – Yes Yes Yes Yes Yes

Maximum GVWR (lbs.) – – – – 26,000 19,500 14,000

Personnel (min) 4 3 3 2 2 2 2

Water Tender ICS Typing

Water Tender Type Support Tactical Requirements S1 S2 S3 T1 T2 Tank capacity 4,000 2,500 1,000 2,000 1,000 Pump minimum flow (gpm) 300 200 200 250 250 At rated pressure (psi) 50 50 50 150 150 Maximum refill time (minutes) 30 20 15 – – Pump and roll – – – Yes Yes Personnel (minimum) 1 1 1 2 2

IRPG – Other References 88

High Pressure Pump Information Max pressure: 360 to 380 psi Weight: 60 lbs. maximum (without fuel can) Fuel Consumption: ≈ 1.2 gal/hr. Minimum Pump Performance at Sea Level: 78 gpm at 100 psi 65 gpm at 150 psi 32 gpm at 250 psi 18 gpm at 300 psi High Pressure Pump Starting Procedures: • Verify correct fuel/oil mixture in fuel tank. Attach fuel line to tank and pump. • Open fuel supply line valve and fuel tank vent. • Attach discharge and suction hose with foot valve and prime pump head. • Move throttle lever to “Start” and “Warm Up” position (center). • Slowly pump fuel bulb until fuel mixture is just touching the bottom of carburetor. • If pump is equipped with on/off switch, turn it on. • On Mark 3 pump, ensure over-speed reset rod is pushed in. • Close choke if engine is cold.

IRPG – Other References 89

• Pull starter rope with short quick pulls until engine “pops.” • Immediately set choke lever to run position. • Pull starter rope approximately 1 to 3 more times and engine should start. • Allow engine to warm up for at least 2 minutes before moving the throttle to the “run” position. • Water must flow through the pump head at all times. Run pump at full throttle, open check and bleeder valve to maintain flow through pump and to control pressure. Use 1” port on check and bleeder valve to re-circulate water back to water source. Mixed Fuel Ratios: • High pressure pumps (all years) – 24:1 • 2 stroke lightweight pumps – 50:1 • Stihl and Husqvarna chainsaws (all years) – 50:1

IRPG – Other References 90

Troubleshooting a High Pressure Pump Symptom: Engine backfires. Possible Cause Remedy Spark plug fouled or Clean or replace. defective.

Symptom: Engine does not start or starts momentarily and then stops. Possible Cause Remedy Fuel supply tank empty. Refill fuel tank. Fuel supply valve closed. Open supply valve. Air vent on fuel tank Open air vent or unscrew cap. closed. Defective fuel supply hose. Replace. Dirty fuel strainer screen. Clean or replace. Leak in fuel supply system. Tighten or replace fittings. Carburetor mountings Tighten mountings. loose. Water or dirt in fuel Drain, then flush thoroughly. system. Too much oil in fuel Mix new batch of fuel. mixture. Engine flooded. Dry the engine. Air filter dirty. Clean or replace. Spark plug fouled or Clean or replace. defective. No spark. Cannot repair in field. Use flagging to identify problem, and return the pump to warehouse. IRPG – Other References 91

Symptom: Engine runs irregularly or misfires. Possible Cause Remedy Defective fuel supply Replace. hose. Dirty fuel strainer screen. Clean or replace. Leak in fuel supply Tighten or replace fittings. system. Carburetor mountings Tighten mountings. loose. Water or dirt in fuel Drain, then flush system. thoroughly. Wrong gasoline in fuel Mix new batch of fuel. mixture. Too much oil in fuel Mix new batch of fuel. mixture. Air filter dirty. Clean or replace. Spark plug fouled or Clean or replace. defective. Wrong type spark plug. Use recommended plug.

Symptom: Engine sounds like a four stroke engine. Possible Cause Remedy Too much oil in fuel mixture. Mix new batch of fuel. Engine not warmed up Allow longer warm up period. properly. Air filter dirty. Clean or replace.

IRPG – Other References 92

Symptom: Engine does not idle properly. Possible Cause Remedy Carburetor mountings Tighten mountings. loose. Too much oil in fuel Mix new batch of fuel. mixture. Spark plug fouled or Clean or replace. defective. Wrong type spark plug. Use recommended plug.

Symptom: Engine does not develop normal power, overheats, or both. Possible Cause Remedy Carburetor mounting loose. Tighten mountings. Wrong gasoline in fuel Mix new batch of fuel. mixture. Wrong oil in fuel mixture. Mix new batch of fuel. Not enough oil in fuel Mix new batch of fuel. mixture. Too much oil in fuel Mix new batch of fuel. mixture. Air filter dirty. Replace. Spark plug fouled or Clean or replace. defective. Wrong type of spark plug. Use recommended plug. Muffler blocked or dirty. Replace.

IRPG – Other References 93

Average Perimeter in Chains Acres Perimeter Acres Perimeter 1 17 75 150 2 24 100 170 3 29 150 200 4 34 200 240 5 38 300 300 7 45 400 350 10 53 500 375 15 65 600 425 20 75 700 450 25 85 800 475 30 90 900 500 40 105 1,000 525 50 120 One Chain = 66 feet

Fire Size Class Class Fire Size A 0 – ¼ acre B ¼ – 10 acres C 10 – 99 acres D 100 – 299 acres E 300 – 999 acres F 1,000 – 4,999 acres G 5,000+ acres

IRPG – Other References 94

Line Spike The “Line Spike,” or “Coyote,” is a progressive line construction technique in which self-sufficient crews build fireline until the end of an operational period, remain overnight (RON) at or near that point, and then begin again the next operational period. Crews should be properly equipped and prepared to spend two or three shifts on the line with minimal support from the incident base. Safety Considerations • Can line spike locations maintain LCES at all times? • Can emergency medical technicians be on the line? • Can a timely medevac plan be implemented? • Can daily communications (verbal and written) be maintained? • Can food and water be provided daily? • Is each crew boss comfortable with the assignment? Operational Considerations • Meals during line spike operational periods may consist of rations and/or sack lunches. • The line spike generally will not last more than two or three operational periods for any one crew. • Division Supervisors will be responsible for establishing on and off operational period times. • Crews working line spike operational periods will be resupplied on the fireline as close as possible to the RON point.

IRPG – Other References 95

Logistical Considerations • Bringing toothbrush/paste, extra socks/underwear, light coat, double lunch, space blanket, etc. • Considering early in the operational period where the crew(s) will RON and that the location provides for safety and logistical needs of the crew (main fire poses no threat, helicopters can longline or land at site, personnel are provided semi-flat ground to sleep on, adequate firewood exists for warming fires, etc.). • Anticipating resupply needs and placing those orders early in the operational period. Crew leaders should make arrangements to have qualified individuals at RON locations to accept those orders by longline or internal helicopter operations. • Take measures to prevent problems with food, trash, etc., in areas where bears are a concern. It’s a common practice to leave one or more individuals with radio communications at the RON location to coordinate the back haul of trash or the pre-positioning of reusable supplies to advanced RON locations. • Determine how crew time and commissary items will be managed. Normally this function can be provided using inbound/outbound helicopter flights at the RON location, or the time is turned in upon returning to the incident base. • Determine how medical emergencies will be managed. An emergency medical technician may be needed at the RON location.

IRPG – Other References 96

Minimum Impact Suppression Tactics The intent of minimum impact suppression tactics (MIST) is to manage a wildland fire with the least impact to natural and cultural resources. Firefighter safety, fire conditions, and good judgment dictate the actions taken. By minimizing impacts of fire management actions, unnecessary resource damage is prevented and cost savings can be realized. These actions include, but are not limited to: Line Construction and Mop Up • Consider: - Cold-trailing fireline. - Using wetline or sprinklers as control line. - Using natural or human-made barriers to limit fire spread. - Burning out sections of fireline. - Limiting width and depth of fireline necessary to limit fire spread. • Locate pumps and fuel sources to minimize impacts to streams. • Minimize cutting of trees and snags to those that pose safety or line construction concerns. • Move or roll downed material out of fireline construction area. • In areas of low spotting potential, allow large- diameter logs to burn out.

IRPG – Other References 97

• Limb only fuels adjacent to the fireline with potential to spread outside the line or produce spotting issues. • Scrape around tree bases near fireline likely to cause fire spread or act as ladder fuel. • Minimize bucking of logs to check/extinguish hot spots; preferably roll logs to extinguish and return logs to original position. • Utilize extensive cold-trailing and/or hot-spot detection devices along perimeter. • Increased use of fireline patrols/monitoring. • Flush-cut stumps after securing fireline. Long Term Incidents • Consult with Resource Advisor to locate suitable campsites. Scout thoroughly to avoid hazards (bee’s nests, widow-makers, etc.). • Plan for appropriate methods of: - Helispot locations - Supply deliveries - Trash backhaul - Disposal of human waste • Minimize ground and vegetation disturbance when establishing sleeping areas. • Use locally approved storage methods to animal- proof food and trash. • When abandoning camp, rehab impacts created by fire personnel.

IRPG – Other References 98

Reporting Fire Chemical Introductions Reporting is required for all introductions of wildland fire chemicals into waterways, or within 300 feet of a waterway if aerially applied. Waterway is any body of water including lakes, rivers, streams and ponds – whether or not they contain aquatic life. Some agencies also require reporting for wildland fire chemicals applied in the habitats of specific threatened and endangered species (TES) identified by the U.S. Fish and Wildlife Service. • If you see anything that suggests fire chemicals may have been introduced into a waterway, the 300-foot buffer zone, or a TES habitat, regardless of delivery method, inform your supervisor. • Information is to be forwarded through the chain of command to the Incident Commander, local Agency Administrator, and/or the Resource Advisor.

IRPG – Other References 99

Fire Origin Protection Checklist • Request wildland fire investigator or law enforcement. • Make notes of all your actions and findings: □ Identify and ask the responsible party and witnesses to remain on scene until fire investigator arrives. □ Name and identification of reporting party. □ En route observations. Include people or vehicles and smoke column color and direction. □ First resources on scene. □ Name and identification of persons or vehicles in vicinity of fire origin. □ Weather observations. • Locate and protect fire origin. □ Do not contaminate area of origin or evidence with trash, cigarette butts, or foot and tire traffic. □ Avoid suppression impacts to origin area, including charred vegetation: - Use fog nozzle. - Establish containment lines to protect area. - Allow heavier fuels to burn down. - Focus on securing the fire perimeter until investigations are complete. • Protect physical evidence. Do not remove unless necessary to prevent destruction. • Take photographs, including close-up views of fire origin area and evidence, if able. • Turn over all notes, information, and physical evidence to fire investigator or law enforcement. • Follow local procedures and policy regarding reporting of cause information. IRPG – Other References 100

Media Interviews • Ensure that the appropriate Public Information Officer or the local Public Affairs office is aware of media visits. • Be prepared. Know the facts. Develop a few key messages and deliver them. Prepare responses to potential tough questions. If possible, talk to reporter beforehand to get an idea of subjects, direction, and slant of the interview. • Be concise. Give simple answers (10-20 seconds), and when you’re done, be quiet. If you botch the answer, simply ask to start again. • Be honest, personable, professional, and presentable (remove sunglasses and hats). • Look at the reporter, not the camera. • Ensure media are escorted and wearing PPE when going to the fireline or hazardous sites. • NEVER talk “off the record,” exaggerate, or try to be cute or funny. • DON’T guess or speculate or say “no comment.” Either explain why you can’t answer the question or offer to track down the answer. • DON’T disagree with the reporter. Instead, tactfully and immediately clarify and correct the information. • DON’T speak for other agencies or offices. • DON’T use jargon or acronyms.

IRPG – Other References 101

Phonetic Alphabet Letter Law Enforcement International A Adam Alpha B Boy Bravo C Charles Charlie D David Delta E Edward Echo F Frank Foxtrot G George Golf H Henry Hotel I Ida India J John Juliet K King Kilo L Lincoln Lima M Mary Mike N Nora November O Ocean Oscar P Paul Papa Q Queen Quebec R Robert Romeo S Sam Sierra T Tom Tango U Union Uniform V Victor Victor W William Whiskey X X-Ray X-Ray Y Young Yankee Z Zebra Zulu

IRPG – Other References 102

NOTES

IRPG – Other References 103

NOTES

IRPG – Other References 104

EMERGENCY M EDICAL CARE– red pages Emergency Medical Care Guidelines Legality: Do only what you are trained and authorized to do. Keep records of what you do for the patient. Blood-Borne Pathogens Use PPE (pocket mask, waterproof gloves, goggles) if contact with body fluids is possible. Treatment Principles • Prevent further injury by removing from danger. • Rapid assessment: Airway, Breathing, Circulation, and life- threatening injuries. • Thorough exam: Look for method of injury. Check for deformities, contusions, abrasions, punctures, burns, tenderness, lacerations, or swelling. • Stabilize patient. • Transport decision: Air or Ground Extraction. • Document on-scene observations and treatment (send with patient). Medical Response Procedures • All injuries must be reported to direct supervisor. • In case of medical emergency, contact incident supervisor or communications dispatcher using the Medical Incident Report on page 118. • Medevac is an incident within an incident. One person needs to become the on-scene incident commander and transfer command later if necessary. • Identify nature of incident, number injured, patient assessment(s), and location (geographic and GPS coordinates). • Do not use patient names on the radio. • Determine transport plan (limited visibility or darkness may delay or negate air transport). IRPG – Emergency Medical Care 105

Patient Assessment Initial Patient Assessment Skin Color . . General impression of patient Normal . . Major bleeding control Pale . . Airway Bluish . . Breathing Flushed/red . Circulation Skin Moisture . Wrist or neck pulse . Normal Patient Information . Dry . . Chief complaint Moist/clammy . . Age & weight Profuse sweating Level of Consciousness Skin Temperature . . Alert & oriented Normal/warm . . Verbal (responds to voice) Hot . . Pain (responds to painful stimuli) Cool . . Unresponsive Cold Breathing Pupils . . Normal Equal or Unequal? . Difficult/labored breathing . Reactive to light . Not breathing? Start rescue . Fixed or Slow breathing response . Dilated or Pulse Constricted . Present . Absent – Start CPR (pg. 108) Make a transport decision

IRPG – Emergency Medical Care 106

Specific Treatments The following injuries may merit immediate transport. Bleeding: Direct pressure, elevate, and tourniquet if the first two actions fail to control extremity bleeding. Shock: Lay patient down, elevate feet, and keep warm. Fractures: Splint joints above and below injury. Monitor pulse and sensation before and after splinting the limb. Head Injury: Stabilize patient’s head and neck, maintain airway. Bee Sting: (or other allergic reaction with rash, face or airway swelling, difficulty talking/breathing): If the patient has an epi kit, assist them in using the medication. Burns: Remove heat source, cool with water, dry wrap, and give fluids if conscious. Eye Injuries: Wash out foreign material. Don’t open swollen eyes. Bandage impaled objects in place, and bandage both eyes if possible. Heat Stroke: Cool body as quickly as possible. See page 109 for additional information.

IRPG – Emergency Medical Care 107

CPR 1. Scene Safety: Look for any dangers or hazards. 2. Determine Responsiveness: Tap on both of the victim’s shoulders and shout, “Are you OK?” Look for chest rise and fall. If the patient is not breathing, continue with steps 3 and 4. If the patient is breathing and no spinal injury is suspected, place patient on his/her side. Continue to monitor breathing. 3. Call for Help: Activate Emergency Response. If possible, obtain an automated external defibrillator (AED). 4. Chest Compressions: Place the heel of one hand on the center of the victim’s chest. Place the other hand over the first and interlock the fingers. Perform compressions at a rate of 100 to 120 per minute, compressing the victim’s chest at least two inches. Push hard and fast. Perform 30 compressions. 5. Airway: Open the victim’s airway by tilting the head back and lifting the chin. If trauma is suspected and you are trained, use the jaw thrust. 6. Breathing: If possible, use a barrier device. Place the barrier device over the victim’s nose and mouth. Pinch the victim’s nose and give 2 breaths, making the chest rise. If no barrier device is available, perform continuous compressions with no breaks or perform mouth-to-mouth. To perform mouth- to-mouth, pinch the victim’s nose and cover the victim’s mouth with your mouth. Form an airtight seal and give two breaths. 7. Continue CPR: Continue alternating 30 compressions and two breaths. If a second rescuer arrives, one person can perform ventilations and one person can perform compressions. Maintain the same 30:2 ratio. 8. AED: If an AED arrives, turn the AED on and follow the instructions provided. IRPG – Emergency Medical Care 108

Heat-Related Injury Definition and Symptoms:

• A heat-related injury (HRI) is a potentially fatal condition caused by elevated body temperatures from internal heat produced by activity or external environmental heat added to the body that cannot be removed to maintain a normal body temperature. • Symptoms of an HRI may be difficult to recognize and may occur in no particular order. If an individual shows any of the symptoms below they should seek medical attention. o Profuse sweating with warm or cool, clammy skin leading to hot dry skin o Muscle cramps and weakness o Dizziness, headache, and irritability o Rapid, weak pulse o Vomiting o Mental status change, as simple as not talking as much o Loss of consciousness Steps to take if a HRI is suspected:

• Cool the body as quickly as possible, then treat other conditions. o Cooling levels will depend on severity

IRPG – Emergency Medical Care 109

o Recovery of high body temperature requires: . Reduction of work output . Removal from sources of heat . Proper nutrition and hydration strategies Considerations for mitigation during firefighting activity: • Heat stress mitigations are not just a shift-to-shift concept. It is also task-to-task and even a minute- to-minute process. • Ability to handle heat is different between individuals and varies on a daily basis. • Performing physical tasks, such as hiking up hills, is our largest producer of body heat. o Hikes into a fire typically raise your body temperature 1–2 ° F from your pre-hike level. • At elevated body temperatures, risk of heat-related injury has a lesser margin of error. • Maintain low skin temperature when possible, as it allows heat transfer from the body. • Pack weights exceeding 25% of body weight add to the demand of an activity. • Work expectations above physical fitness levels can increase risk of HRI.

IRPG – Emergency Medical Care 110

Burn Injuries • INITIATE MEDEVAC IMMEDIATELY. • Remove person from heat source while looking for signs of a burned airway (e.g., singed facial hair, nasal hairs, soot, or burns around or in nose, mouth, black sooty sputum, etc.). • Apply cool, clear water over burned area. Do not soak person or use cold water and ice packs, as this may cause hypothermia. • Examine for other injuries. - Provide basic first aid. - Monitor airway, breathing, circulation (ABCs). - Treat for shock by keeping person warm, feet elevated. - Provide oxygen, if available and trained to administer. • Assess degree of burn and area affected. □ First Degree (Superficial) Red, mild to moderate pain. □ Second Degree (Partial Thickness) Skin may be red and raw, blistered, swollen, painful to very painful.

IRPG – Emergency Medical Care 111

□ Third Degree (Full Thickness) Whitish, charred, or translucent, no pin prick sensation in burned area. □ Rule of Palms: Patient’s palm = 1% of their body surface. Estimate how many times the patient’s palm could be placed over the burned areas to estimate the % of body that has been burned. • Cut away only burned clothing. Do not cut away clothing stuck to burned skin. Remove jewelry near injured area. • Cover burned area with clean, dry dressing, and moisten with clean water, and apply dry dressing on top. • For severe burns or burns covering large area of body: - Wrap with a clean sheet followed by plastic sheet. - Place inside sleeping bag or cover with insulated blanket. • Monitor ABCs and keep burn areas moist with clean water. • Avoid hypothermia and overheating.

IRPG – Emergency Medical Care 112

Multi-Casualty Triage System

Color Priority Description

Red Immediate Serious, life-threatening injury. Breathing but unconscious; respirations more than 30/minute. Radial pulse absent, capillary refill more than 2 seconds. Or can’t follow simple commands.

Yellow Delayed Treatment and transport delayed. Respirations less than 30/minute. Radial pulse present, capillary refill less than 2 seconds. And can follow simple commands.

Green Minor All walking wounded; treatment can be delayed.

Black Deceased/ Dead or with injuries not Dying compatible with life. No respirations after repositioning airway.

IRPG – Emergency Medical Care 113

Injury/Fatality Procedures

Serious Injury: • Give first aid - call for medical aid and transportation if needed. • Do not release victim's name except to authorities. • Never broadcast victim's name on the radio. • Do not allow unauthorized picture taking or release of pictures. • Notify Incident Commander, who will: - Assign a person to supervise evacuation, if necessary, and stay with the victim until under medical care. In rough terrain, at least 15 workers will be required to carry a stretcher. - Assign person to get facts and witness statements and preserve evidence until investigation can be taken over by the Safety Officer or appointed investigating team. - Notify the Agency Administrator.

IRPG – Emergency Medical Care 114

Fatality: • Do not move the body unless it is in a location where it could be burned or otherwise destroyed. Secure accident scene. • Do not release victim's name except to authorities. • Never broadcast victim's name on air. • Do not allow unauthorized picture taking or release of pictures. • Notify Incident Commander, who will: - Assign person to start investigation until relieved by appointed investigating team. - Notify Agency Administrator and report essential facts. The Agency Administrator will notify proper authorities and next of kin as prescribed by agency regulations. - If requested, assist authorities in transporting remains. - Mark location of body on ground. Note location of tools, equipment, or personal gear. - Retain PPE as evidence.

IRPG – Emergency Medical Care 115

Helicopter Extraction Operations The intent of helicopter extraction operations is to insert qualified personnel into inaccessible areas to extract a patient for transport to the nearest medical facility. These operations are not meant to be a medical transport resource; life flight or ground transport should be ordered in addition to the extraction aircraft and crew. ORDERING: • On-scene EMT or Medical Incident IC determines/ requests that medical extraction is required and coordinates the order through the IMT or local dispatch. • Use the Medical Incident Report (p.118). Include the patient weight and name of on-scene radio contact. • Establish communications with incoming aircrew. Provide the following information: known hazards, terrain, wind speed/direction, patient update. CONSIDERATIONS: • Choose extraction site away from fireline or black edge. • Ensure the area is clear of non-essential items and personnel. Follow the directions of the aircrew.

IRPG – Emergency Medical Care 116

• Rotor wash may affect overhead hazards and blowing dust/debris can create “brown out” conditions. • Aerial Supervision is valuable for coordinating aviation medevac missions. • The aircrew will make the final assessment regarding the safety of the mission. Always have a contingency plan in case a helicopter cannot be used. • It is easy to become caught up in the urgency of a mission, especially those involving life- threatening situations. Regardless of the emergency, follow basic fireline and aviation safety procedures. Rescue Hoist: A cable winching device mounted to the helicopter that is capable of lowering/raising persons attached to the cable.

Short-haul: To transport one or more persons suspended on a fixed line beneath a helicopter. The intent is to transport persons a short distance (short- haul), normally from a limited or inaccessible location to a safe landing area.

IRPG – Emergency Medical Care 117

Medical Incident Report FOR A NON-EMERGENCY INCIDENT, WORK THROUGH CHAIN OF COMMAND TO REPORT AND TRANSPORT INJURED PERSONNEL AS NECESSARY. FOR A MEDICAL EMERGENCY: IDENTIFY ON-SCENE INCIDENT COMMANDER BY NAME AND POSITION AND ANNOUNCE "MEDICAL EMERGENCY" TO INITIATE RESPONSE FROM IMT COMMUNICATIONS/DISPATCH. Use the following items to communicate situation to communications/dispatch. 1. CONTACT COMMUNICATIONS / DISPATCH (Verify correct frequency prior to starting report) Ex: "Communications, Div. Alpha. Stand-by for Emergency Traffic." 2. INCIDENT STATUS: Provide incident summary (including number of patients) and command structure. .Ex: “Communications, I have a Red priority patient, unconscious, struck by a falling tree. Requesting air ambulance to Forest Road 1 at (Lat. / Long.) This will be the Trout Meadow Medical, IC is TFLD Jones. EMT Smith is providing medical care.”

☐ RED / PRIORITY 1 Life or limb threatening injury or illness. Evacuation need is IMMEDIATE. Ex: Unconscious, difficulty breathing, bleeding severely, 2° – 3° Severity of burns more than 4 palm sizes, heat stroke, disoriented. Emergency / ☐ YELLOW / PRIORITY 2 Serious Injury or illness. Transport Evacuation may be DELAYED if necessary. Ex: Priority Significant trauma, unable to walk, 2° – 3° burns not more than 1-3 palm sizes. ☐ GREEN / PRIORITY 3 Minor Injury or illness. Non-Emergency transport. Ex: Sprains, strains, minor heat-related illness. Nature of Injury Brief Summary of Injury or or Illness & Illness (Ex: Unconscious, Mechanism of Struck by Falling Tree) Injury Air Ambulance / Short- Transport Haul/Hoist/ Ground Request Ambulance / Other Patient Descriptive Location & Lat. / Location Long. (WGS84)

IRPG – Emergency Medical Care 118

Geographic Name + Incident Name "Medical" (Ex: Trout Meadow Medical) On-Scene Name of on-scene IC of Incident Incident within an Incident Commander (Ex: TFLD Jones) Name of Care Provider (Ex: Patient Care EMT Smith) 3. INITIAL PATIENT ASSESSMENT: Complete this section for each patient as applicable (start with the most severe patient). Patient Assessment: See IRPG page 106 Treatment: 4. TRANSPORT PLAN: Evacuation Location (if different): (Descriptive Location (drop point, intersection, etc.) or Lat. / Long.) Patient's ETA to Evacuation Location: Helispot / Extraction Site Size and Hazards: 5. ADDITIONAL RESOURCES / EQUIPMENT NEEDS: Example: Paramedic/EMT, Crews, Immobilization Devices, AED, Oxygen, Trauma Bag, IV/Fluid(s), Splints, Rope rescue, Wheeled litter, HAZMAT, Extrication 6. COMMUNICATIONS: Identify State Air/Ground EMS Frequencies and Hospital Contacts as applicable. Channel Receive Tone/ Transmit Tone/ Function Name/# (RX) NAC* (TX) NAC COMMAND AIR-TO- GROUND TACTICAL 7. CONTINGENCY: Considerations: If primary options fail, what actions can be implemented in conjunction with primary evacuation method? Be thinking ahead. 8. ADDITIONAL INFORMATION: Updates/Changes, etc. REMEMBER: • Confirm ETA's of resources ordered. • Act according to your level of training. • Be Alert. Keep Calm. Think Clearly. Act Decisively IRPG – Emergency Medical Care 119

The Incident Response Pocket Guide (IRPG) is developed and maintained by the Operations and Training Committee (OTC), an entity of the National Wildfire Coordinating Group (NWCG). Previous editions: 2014, 2010, 2006, 2004, 2002, 1999. While they may still contain current or useful information, previous editions are obsolete. The user of this information is responsible for confirming that they have the most up-to-date version. NWCG is the sole source for this publication. This publication is available electronically at. https://www.nwcg.gov/sites/default/files/publications/pms461.pdf Printed copies of this guide may be ordered from the Great Basin Cache at the National Interagency Fire Center in Boise, Idaho. Refer to the annual NFES Catalog Part 2: Publications and find ordering procedures at https://www.nwcg.gov/catalogs-ordering- quicklinks. Comments or questions may be submitted to the appropriate agency program manager assigned to OTC. View the complete roster at https://www.nwcg.gov/committees/operations-and- training-committee. Publications and training materials produced by the National Wildfire Coordinating Group (NWCG) are in the public domain. Use of public domain information, including copying, is permitted. Use of NWCG information within another document is permitted if NWCG information is accurately credited to NWCG. The NWCG logo may not be used except on NWCG authorized information. “National Wildfire Coordinating Group,” “NWCG,” and the NWCG logo are trademarks of NWCG. The use of trade, firm, or corporation names or trademarks in NWCG products is solely for the information and convenience of the reader and does not constitute endorsement by NWCG or its member agencies or any product or service to the exclusion of others that may be suitable.

IRPG 120 BRIEFING CHECKLIST Situation □ Fire name, location, map orientation, other incidents in area □ Terrain influences □ Fuel type and conditions □ Fire weather (previous, current, and expected) □ Winds, RH, temperature, etc. □ Fire behavior (previous, current, and expected) Time of day, alignment of slope and wind, etc. Mission/Execution □ Command Incident Commander/immediate supervisor □ Leader’s intent Overall objectives/strategy □ Specific tactical assignments □ Contingency plans □ Medevac plan: Personnel, equipment, transport options, contingency plans Communications □ Communication plan Tactical, command, air-to-ground frequencies Cell phone numbers Service/Support □ Other resources Working adjacent and those available to order Aviation operations □ Logistics Transportation Supplies and equipment Risk Management □ Identify known hazards and risks □ Identify control measures to mitigate hazards/reduce risk o Include LCES □ Identify trigger points for reevaluating operations Questions or Concerns? STANDARD FIREFIGHTING ORDERS 1. Keep informed on fire weather conditions and forecasts. 2. Know what your fire is doing at all times. 3. Base all actions on current and expected behavior of the fire. 4. Identify escape routes and safety zones, and make them known. 5. Post lookouts when there is possible danger. 6. Be alert. Keep calm. Think clearly. Act decisively. 7. Maintain prompt communications with your forces, your supervisor, and adjoining forces. 8. Give clear instructions and be sure they are understood. 9. Maintain control of your forces at all times. 10. Fight fire aggressively, having provided for safety first. WATCH OUT SITUATIONS 1. Fire not scouted and sized up. 2. In country not seen in daylight. 3. Safety zones and escape routes not identified. 4. Unfamiliar with weather and local factors influencing fire behavior. 5. Uninformed on strategy, tactics, and hazards. 6. Instructions and assignments not clear. 7. No communication link with crewmembers or supervisor. 8. Constructing line without safe anchor point. 9. Building fireline downhill with fire below. 10. Attempting frontal assault on fire. 11. Unburned fuel between you and fire. 12. Cannot see main fire; not in contact with someone who can. 13. On a hillside where rolling material can ignite fuel below. 14. Weather becoming hotter and drier. 15. Wind increases and/or changes direction. 16. Getting frequent spot fires across line. 17. Terrain and fuels make escape to safety zones difficult. 18. Taking a nap near fireline. Fire Environment Visualization

Determining distances from known points on a map is rather simple. But when you are in the field, it is another matter, unless you can relate to something known. How long are those flame lengths? Or how fast is this fire spreading? Obviously direct measurement is the most accurate way to make determinations. But how do you physically measure flame length on a high intensity fire? Is it important to know spread distance in feet or chains per hour? Using references in the field (something of known length or size) are very good aids to make calculated estimates of fire behavior. Learn to visualize the fire environment.

Visualization tools: What is the average canopy height of the trees? Telephone poles are about 30 feet tall. Fence posts are about 5 feet tall. How tall is the brush or grass you are standing next to, which is also the same fuel the fire is consuming? By relating flame length to the height of a known object, you can come up with a ratio to estimate. Example: Trees in the area are 40 feet tall. Flame lengths are one-half the height of the trees. Average flame length is about 20 feet (.5x the height of the trees in this example).

An effective way to estimate rate of spread is to know how much time it takes to burn between two known points. To determine spread distance, measure the distance between two points. Start timing when fire reaches the first point, and stop timing when fire reaches the second point. This establishes a ratio, which then can be mathematically applied to a unit of measure and time (ft/min, chains/hour, or miles/hour).

Other aids include using the odometer in a vehicle or by pacing to establish known ground distance. Range finders are useful if you have one. Barbed wire fence posts are about 1 rod (16.5 feet) apart. The distance between 4 fence posts then is 1 chain (66 feet). Although more variable, the distance between telephone poles is about 132 feet. On a larger scale and using a map, you can relate terrain features to distance and get a good idea of how quickly a fire is advancing. Another hint: Most detection reports list a time of discovery. By estimating how far the fire has traveled upon your arrival and noting your arrival time, you can determine fire spread. But a word of caution: the fire environment is dynamic (changing with time and space). What occurred in the past may be of value, but may not apply to the current situation or what could happen in the near future. For safety reasons, base all your actions on current conditions, the forecasted expected conditions, and what the fire is doing (fire behavior).

Awareness and relationships tend to be more important than actual measurements. In this course you are going to learn more about fire events which don’t require a lot of math or figuring. When is the next “Big Change” coming? Is it very little, such as a 2-fold (2x) increase, or is it a big change, such as a 60-fold (60x) change? When the change happens, are fire fighters at risk? Is there enough time to get to a safety zone when the change comes? Understanding the fire environment along with the magnitude of the “big change” is the key.

NWCG FIRELINE HANDBOOK APPENDIX B FIRE BEHAVIOR

APRIL, 2006 PMS 410-2 NFES 2165

Additional copies of this publication may be ordered from:

National Interagency Fire Center ATTN: Supply 3833 S. Development Avenue Boise, Idaho 83705

Order NFES 2165

B-1 CONTENTS

PURPOSE ...... 4

FIRE BEHAVIOR WORKSHEETS ...... 5

INPUT 0–Projection Point ...... 10

INPUT 1–Selecting a Fuel Model ...... 10 Fire Behavior Fuel Model Key ...... 12 Fire Behavior Fuel Model Descriptions ...... 16 Grass Group ...... 16 Shrub Group ...... 17 Timber Litter Group ...... 18 Logging Slash Group ...... 19 Table 1–Description of Fuel Models ...... 21

INPUT 2–Fine Dead Fuel Moisture (1-H FDFM) ...... 22 Table 2–Reference Fuel Moisture, Day (0800-1959) ...... 25 Table 3–Dead Fuel Moisture Content Corrections, Day (0800-1959) May, June, July ...... 26 Table 4–Dead Fuel Moisture Content Corrections, Day (0800-1759) February, March, April, August, September, October ...... 27 Table 5–Fine Dead Fuel Moisture Content Corrections, Day (0800-1759) November, December, January ...... 28

INPUT 3–Live Fuel Moisture (LFM) Fuel Models 2, 4, 5, 7 and 10 ...... 29 Table 6–Live Fuel (Foliage) Moisture Content % ...... 29

INPUT 4–Midflame Windspeed (MFWS) ...... 30 Diagram 1: 20-Foot Windspeed Adjusted to Midflame Windspeed Based on Overstory...... 32 Table 7–Wind Adjustment Table ...... 33 Table 8–Modified Beaufort Scale for Estimating 20-Foot Windspeed ...... 34

INPUT 5–Slope (SLP) ...... 35 Slope Determination Process ...... 35 Table 9–Map Scale Conversion Factors ...... 36

B-2 CONTENTS (continued)

INPUT 6–Effective Windspeed (EWS) ...... 37

FIRE BEHAVIOR OUTPUTS

OUTPUT 1–Rate of Spread ...... 38 OUTPUT 2–Heat Per Unit Area ...... 38 OUTPUT 3–Fireline Intensity ...... 38 OUTPUT 4–Flame Length ...... 38 OUTPUT 5–Spread Distance ...... 38

OUTPUT 6/7–Projected Fire Perimeter and Area ...... 40 Table 10–Perimeter Estimations for Point Source Fires ..... 41 Table 11–Area Estimations for Point Source Fires ...... 44 Diagram 2: Approximate Fire Shapes for Various Effective Windspeeds ...... 47

OUTPUT 8–Maximum Spotting Distance ...... 48 Nomogram 1–Flame Height ...... 50 Nomogram 2–Flame Duration ...... 51 Nomogram 3–Ratio of Lofted Firebrand Height to Flame Height ...... 52 Nomogram 4–Maximum Spotting Distance ...... 53

OUTPUT 9–Probability of Ignition ...... 54 Table 12–Probability of Ignition Table ...... 55

INTERPRETATION OF FIRE BEHAVIOR INFORMATION

Table 13–Fire Severity Related to Fuel Moisture Chart ..... 56 Diagram 3: Fire Behavior Characteristics Chart (Light Fuel) ...... 57 Diagram 4: Fire Behavior Characteristics Chart (Heavy Fuel) ...... 58 Table 14–Fire Suppression Interpretations ...... 59

SAFETY AND FIRE BEHAVIOR ...... 60 Look Up/Look Down/Look Around ...... 61

Tables 15 through 78 – Rate of Spread and Flame Length Tables by Fuel Type and Percent Slope ...... 63

B-3 PURPOSE

The purpose of this appendix is to provide some basic fire behavior information that will enable a person with a moderate level of fire behavior training (Introduction to Wildland Fire Behavior Calculations, S-390) to predict and calculate some basic elements of fire behavior and fire size.

Information in this appendix will provide the qualified user with the means to:

• Predict rate of spread (ROS) and flame length (FL) for each Fire Behavior Fuel Model based on the 1-hour timelag dead fuel moisture, live fuel moisture for Fuel Models 2, 4, 5, 7 and 10, midflame windspeed and percent slope.

• Estimate the area and perimeter of a fire, given inputs of spread distance (rate of spread x time) and midflame windspeed.

• Predict maximum spotting distance and probability of ignition.

• Provide worksheets for fire behavior prediction.

The Fire Behavior Worksheet is on page B-5. Other worksheets that help track fire behavior input and output date (Fine Dead Fuel Moisture/Probability of Ignition, Wind Adjustment, Slope, Map- Spread, Size, Spotting, and Map-Spot) are provided on pages B-6 through B-9. Pages B-10 through B-37 go over the six required input items on the Fire Behavior Worksheet and B-38 through B-55 cover the output items.

It is imperative that the user of information contained in this appendix know the assumptions, limitations, and appropriate uses of fire behavior prediction models and is able to recognize how environmental factors and processes affect fire behavior predictions and safety.

B-4 FIRE BEHAVIOR WORKSHEET

NAME OF FIRE ______FIRE PRED SPEC______DATE______TIME______

PROJ PERIOD DATE______PROJ TIME FROM _____TO____

INPUT 0 PP PROJECTION POINT ______1 MODEL# FUEL MODEL NUMB (1-13) ______2 1H-FDFM FINE DEAD FUEL MOIST, % ______3 LFM LIVE FUEL MOISTURE, % ______4 MFWS MIDFLAME WINDSPD, mi/h ______5 SLP SLOPE, % ______6 EWS EFFECTIVE WNDSPD, mi/h ______

OUTPUT 1 ROS RATE OF SPREAD, ch/h ______2 HA HEAT PER UNIT AREA, ______Btu/sq ft 3 FLI FIRELINE INTENSITY, ______Btu/ft/s 4 FL FLAME LENGTH, ft ______5 SD SPREAD DISTANCE, ch ______MAP SPREAD DIST, in 6 PER PERIMETER, ch ______7 AC AREA, ac ______8 SPOT MAX SPOTTING DIST, mi ______MAP DIST SPOT, in ______9 PIG PROB OF IGNITION, % ______

B-5 FINE DEAD FUEL MOISTURE/PROBABILITY OF IGNITION WORKSHEET

INPUT 0 PP PROJECTION POINT ______1 D DAY TIME CALCULATION D D D 2 DB DRY BULB TEMP. °F ______3 WB WET BULB TEMP. °F ______4 DP DEW POINT, °F ______5 RH RELATIVE HUMIDITY, % ______6 RFM REFERENCE FUEL ______MOIST, % (TABLE 2) 7 MO MONTH ______8 SH UNSHADED (U) U/S U/S U/S SHADED (S) 9 T TIME ______10 CH ELEVATION CHANGE B/L/A B/L/A B/L/A B = 1000' to 2000' below site L = +1000' of site location A = 1000' to 2000' above site 11 ASP ASPECT, (N, E, S, W) ______12 SLP SLOPE % ______13 FMC FUEL MOIST CORRECT, % ______(TABLE 3, 4, OR 5)

OUTPUT 1 1H- FINE DEAD FUEL MOIST, % ______FDFM (line 6 + line 13) 2 PIG PROB OF IGNITION, % ______(TABLE 12)

B-6 WIND ADJUSTMENT WORKSHEET

INPUT 0 PP PROJECTION POINT ______1 20' W 20-FT WINDSPEED, mi/h ______2 MODEL # FUEL MODEL # (1-13) ______3 SHLTR WIND SHELTERING ______1=Unsheltered 2=Partially Sheltered 3=Fully Sheltered, Open 4=Fully Sheltered, Closed 4 WAF WIND ADJUST FACTOR ______(TABLE 7)

OUTPUT 1 MFWS MIDFLAME WNDSPD, mi/h ______(line 1 x line 4)

SLOPE WORKSHEET

INPUT 0 PP PROJECTION POINT ______1 CON INT CONTOUR INTERVAL ______2 SLC MAP SCALE ______3 CF CONVERSION FACTOR, ______ft/in 4 # INTVLS # CONTOUR INTERVALS ______5 RISE RISE IN ELEVATION ______6 MD MAP DISTANCE, in ______(Between Points) 7 HZGD HORIZ GROUND DIST, ft ______

OUTPUT 1 SLP % SLOPE, % ______B-7 MAP-SPREAD WORKSHEET

INPUT 0 PP PROJECTION POINT ______1 ROS RATE OF SPREAD, ch/h ______2 PT PROJECTION TIME, hr ______3 SDCH SPREAD DISTANCE, ch ______(line 1 x line 2) 4 SDFT SPREAD DISTANCE, ft ______(line 3 x 66 ft/ch) 5 SCL MAP SCALE ______6 CF CONVERSION FACTOR, ______ft/in (See Map Scale Conversion)

OUTPUT 1 MD MAP SPREAD DIST, in ______(line 4 divided by line 6)

SIZE WORKSHEET

INPUT 0 PP PROJECTION POINT ______1 ROS RATE OF SPREAD, ch/h ______2 EWS EFFECTIVE WINDSPD, mi/h ______3 PT PROJECTION TIME, hr ______4 SD SPREAD DISTANCE, ch ______(line 1 x line 3 = line 4)

OUTPUT 1 PER PERIMETER, ch ______2 AC AREA, ac ______

B-8 SPOTTING WORKSHEET

MAP-SPOT WORKSHEET

INPUT 0 PP PROJECTION POINT ______1 SPOTMI SPOTTING DISTANCE, mi ______2 SPOTFT SPOTTING DISTANCE, ft ______(line 1 x 5,280 ft) 3 SCL MAP SCALE ______4 CF CONVERSION FACTOR, ______ft/in

OUTPUT 1 SPOT MAP DISTANCE SPOT, in ______(line 2 divided by line 4)

B-9 COMPLETING THE FIRE BEHAVIOR WORKSHEET

INPUT 0: Projection Point (PP)

Assign a number or letter to designate the projection point location and enter as Input 0 on the Fire Behavior Worksheet on page B-5.

INPUT 1: Fuel Model (Model #)

• Using the guidelines below, proceed through the fuel model key and descriptions which follow and select a fuel model and enter as Input 1 on the Fire Behavior Worksheet on page B-5.

• Determine the primary carrier of fire.

• Determine which stratum of the surface fuels is most likely to carry the spreading fire (grass, needle litter, leaves, logging slash, etc.).

• Determine the appropriate fuel group/general vegetation type; i.e., Grass (Models 1-3), Shrub (Models 4-7), Timber Litter (Models 8-10), or Logging Slash (Models 11-13).

• Using the fuel model key, determine the appropriate fuel model.

• Go to the fuel model description and determine if it fits.

• If yes, use it and enter into Input 1 on the Fire Behavior Worksheet.

• If no, find another that more closely fits your situation.

• The fuel models used here are those used by Albini (1976)¹ to develop the nomograms published in his paper Estimating Wildfire Behavior and Effects. There are 13 models which are called the Fire Behavior Fuel Models.

¹ Albini Frank A.; Estimating Wildfire Behavior and Effects. Gen. Tech. Report INT-30; 1976.

B-10 They are tuned to the fine fuels that carry the fire and thus describe the conditions at the head of the fire or the flaming front. These models are designed to give predictions for fire spread at a steady rate. It is important to recognize that rate of spread (ROS) and flame length (FL) predictions are estimates and the actual ROS and FL may vary considerably from the predicted.

• Assessment of fire behavior is simpler if a single fuel model is used to describe the fuels in the area. In fact, as experience is gained by observation of fires and estimating their behavior, it is possible to pick the fuel model not only by its description of physical vegetation, but also by its known fire behavior characteristics.

Examples: The fire may be in timbered area, but the timber is relatively open and dead grass, not needle litter, is the stratum carrying the fire. In this case, Fuel Model 2, which is not listed as a timber model, should be considered, or

In the same area if the grass is sparse and there is no wind or slope, the needle litter would be the stratum carrying the fire and Fuel Model 9 would be the better choice.

• Determine the general depth and compactness of the fuel. This information will be needed when using the fuel model key. There are very important considerations when matching fuels, particularly in the grass and timber types.

• Determine which fuel models are present and what their influence on fire behavior is expected to be.

Example: Green fuel may be present, but will it play a significant role in fire behavior? Large fuels may be present, but are they sound, or decaying and breaking up? Do they have limbs and twigs attached or are they bare cylinders? Look for the fine fuels and choose a model that represents their depth, compactness, and to some extent, the amount of live fuel and its contribution to fire. Do not be restricted by the model name or the original intended application.

B-11 FIRE BEHAVIOR FUEL MODEL KEY¹

I. PRIMARY CARRIER OF THE FIRE IS GRASS. Expected rate of spread is moderate to high, with low to moderate fireline intensity (flame length).

A. Grass is fine structured, generally below knee level, and cured or primarily dead. Grass is essentially continuous. SEE THE DESCRIPTION OF MODEL 1.

B. Grass is coarse structured, above knee level (averaging about 3 ft.) and is difficult to walk through. SEE THE DESCRIPTION OF MODEL 3.

C. Grass is usually under an open timber or brush overstory. Litter from the overstory is involved, but grass carries the fire. Expected spread rate is slower than Fuel Model 1 and intensity is less than Fuel Model 3. SEE THE DESCRIPTION OF MODEL 2.

¹ Richard C. Rothermel; How to Predict the Spread and Intensity of Forest and Range Fires. Gen. Tech Report INT-143; June 1983 (NFES 1574).

B-12 II. PRIMARY CARRIER OF THE FIRE IS SHRUB or LITTER BENEATH SHRUB. Expected rates of spread and fireline intensities (flame length) are moderate to high.

A. Vegetative type is southern rough or low pocosin. Shrub is generally 2 to 4 ft. high. SEE THE DESCRIPTION OF MODEL 7.

B. Live fuels are absent or sparse. Brush averages 2 to 4 ft. in height. Brush requires moderate winds to carry fire. SEE THE DESCRIPTION OF MODEL 6.

C. Live fuel moisture can have a significant effect on fire behavior.

1. Shrub is about 2 ft. high, with light loading of brush litter underneath. Litter may carry the fire, especially at low windspeeds. SEE THE DESCRIPTION OF MODEL 5.

2. Shrub is head-high (6 ft.), with heavy loadings of dead (woody) fuel. Very intense fire with high spread rates expected. SEE THE DESCRIPTION OF MODEL 4.

3. Vegetative type is high pocosin. SEE THE DESCRIPTION OF MODEL 4.

B-13 III. PRIMARY CARRIER OF THE FIRE IS LITTER BENEATH A TIMBER STAND. Spread rates are low to moderate, fireline intensity (flame length) may be low to high.

A. Surface fuels are mostly foliage litter. Large fuels are scattered and lie on the foliage litter, that is, large fuels are not supported above the litter by their branches. Green fuels are scattered enough to be insignificant to fire behavior.

1. Dead foliage is tightly compacted, short needle (2 inches or less) conifer litter or hardwood litter. SEE THE DESCRIPTION OF MODEL 8.

2. Dead foliage litter is loosely compacted long needle pine or hardwoods. SEE THE DESCRIPTION OF MODEL 9.

B. There is a significant amount of larger fuels with attached branches and twigs, or it has rotted enough that it is splintered and broken. The larger fuels are fairly well distributed over the area. Some green fuel may be present. Overall depth of the fuel is primarily below the knees, but some fuel may be higher. SEE THE DESCRIPTION OF MODEL 10.

IV. PRIMARY CARRIER OF THE FIRE IS LOGGING SLASH. Spread rates are low to high, fireline intensities (flame lengths) are low to very high.

A. Slash is aged and overgrown.

1. Slash is from hardwood trees. Leaves have fallen and cured. Considerable vegetation (tall weeds) has grown in amid the slash and has cured or dried out. SEE THE DESCRIPTION OF MODEL 6.

2. Slash is from conifers. Needles have fallen and considerable vegetation (tall weeds and some shrubs) has overgrown the slash. SEE THE DESCRIPTION OF MODEL 10.

B-14 B. Slash is fresh (0-3 years) and not overly compacted.

1. Slash is not continuous. Needle litter or small amounts of grass or shrubs must be present to help carry the fire, but primary carrier is still slash. Live fuels are absent or do not play a significant role in fire behavior. The slash depth is about 1 ft. SEE THE DESCRIPTION OF MODEL 11.

2. Slash generally covers the ground (heavier loadings than Model 11), though there may be some bare spots or areas of light coverage. Average slash depth is about 2 ft. Slash is not excessively compacted. Approximately one-half of the needles may still be on the branches but are not red. Live fuels are absent, or are not expected to affect fire behavior. SEE THE DESCRIPTION OF MODEL 12.

3. Slash is continuous or nearly so (heavier loadings than Model 12). Slash is not compacted and has an average depth of 3 ft. Approximately one-half of the needles are still on the branches and are red, OR all the needles are on the branches but they are green. Live fuels are not expected to influence fire behavior. SEE THE DESCRIPTION OF MODEL 13.

4. Same as 3, EXCEPT all the needles are attached and are red. SEE THE DESCRIPTION OF MODEL 4.

B-15 FIRE BEHAVIOR FUEL MODEL DESCRIPTIONS²

• Grass Group

Fuel Model 1 (1 foot deep) Fire spread is governed by the fine herbaceous fuels that have cured or are nearly cured. Fires are surface fires that move rapidly through cured grass and associated material. Very little shrub or timber is present, generally less than one-third of the area.

Grasslands and savanna are represented along with stubble, grass-tundra, and grass-shrub combinations that meet the above area constraint. Annual and perennial grasses are included in this fuel model.

Fuel Model 2 (1 foot deep) Fire spread is primarily through the fine herbaceous fuels, either curing or dead. These are surface fires where the herbaceous material, besides litter and dead-down stemwood from the open shrub or timer overstory, contribute to the fire intensity. Open shrub lands and pine stands or scrub oak stands that cover 1/3 to 2/3 of the area may generally fit this model but may include clumps of fuels that generate higher intensities and may produce firebrands. Some pinyon-juniper may be in this model.

Fuel Model 3 (2.5 feet deep) Fires in this fuel are the most intense of the grass group and display high rates of spread under the influence of wind. The fire may be driven into the upper heights of the grass stand by the wind and cross over standing water. Stands are tall, averaging about 3 feet, but considerable variation may occur. Approximately one-third or more of the stand is considered dead or cured and maintains the fire.

² Anderson, Hal E.; Aids to Determining Fuel Models for Estimating Fire Behavior. Gen. Tech Report INT-122, 1982.

B-16 • Shrub Group

Fuel Model 4 (6 feet deep) Fire intensity and fast spreading fires involve the foliage and live and dead fine woody materials in the crowns of a nearly continuous secondary overstory. Examples are stands of mature shrub, 6 or more feet tall, such as California mixed chaparral, the high pocosins along the east coast, the pine barrens of New Jersey or the closed jack pine stands of the north-central states. Besides flammable foliage, there is dead woody material in the stand that significantly contributes to the fire intensity. Height of stands qualifying for this model vary with local conditions. There may be also a deep litter layer that confounds suppression efforts.

Fuel Model 5 (2 feet deep) Fire is generally carried in the surface fuels made up of litter cast by the shrubs and the grasses or forbs in the understory. Fires are generally not very intense as surface fuel loads are light, the shrubs are young with little dead material, and the foliage contains little volatile material. Shrubs are generally not tall, but nearly cover the entire area. Young, green stands with little or no deadwood such as laurel, vine maple, alder, or even chaparral, manzanita, or chamise are examples. As the shrub fuel moisture drops, consider using a Fuel Model 6.

Fuel Model 6 (2.5 feet deep) Fires carry through the shrub layer where the foliage is more flammable than Fuel Model 5, but require moderate winds (>8 mi/h) at midflame height. Fire will drop to the ground at low windspeeds or openings in the stand. Shrubs are older, but not as tall as shrub types of Model 4, nor do they contain as much fuel as Model 4. A broad range of shrub conditions is covered by this model. Typical examples include intermediate stands of chamise, chaparral, oak brush, low pocosins, Alaskan spruce taiga, and shrub tundra. Cured hardwood slash can be considered. Pinyon-juniper shrublands may fit, but may overpredict rate of spread except at high winds (20 mi/h at the 20-foot level).

B-17 Fuel Model 7 (2.5 feet deep) Fire burns through the surface and shrub strata equally. Fire can occur at higher dead fuel moisture contents due to the flammable nature of live foliage. Shrubs are generally 2 to 6 feet high. Examples are Palmetto- gallberry understory-pine overstory sites, low pocosins, and Alaska Black Spruce-shrub combinations.

• Timber Litter Group

Fuel Model 8 (0.2 foot deep) Slow burning ground fires with low flame heights are generally the case, although an occasional “jackpot” or heavy fuel concentration may cause a flare up. Only under severe weather conditions do these fuels pose fire problems. Closed-canopy stands of short needle conifers or hardwoods that have leafed out support fire in the compact litter layer. This layer is mainly needles, leaves, and some twigs since little undergrowth is present in the stand. Representative conifer types are white pine, lodgepole pine, spruce, true fires, and larches.

Fuel Model 9 (0.2 foot deep) Fires run through the surface litter faster than model 8 and have higher flame height. Both long-needle conifer and hardwood stands, especially the oak- hickory types, are typical. Fall fires in hardwoods are representative, but high winds will actually cause higher rates of spread than predicted because of spotting caused by rolling blowing leaves. Closed stands of long-needled pine like ponderosa, Jeffrey, and red pines or southern pine plantations are grouped in this model. Concentrations of dead-down woody material will contribute to possible torching out of trees, spotting, and crowning activity.

B-18 Fuel Model 10 (1 foot deep) The fires burn in the surface and ground fuels with greater fire intensity than other timber litter models. Dead-down fuels include greater quantities of 3-inch or larger limb wood resulting from over-maturity or natural events that create a large load of dead material on the forest floor. Crowning out, spotting, and torching of individual trees are more frequent in this fuel situation leading to potential fire control difficulties. Any forest type may be considered when heavy down materials are present; examples are insect or diseased stands, wind-thrown stands, over-mature situations with deadfall, and cured light thinning or partial-cut slash.

• Logging Slash Group

Fuel Model 11¹ (1 foot deep) Fires are fairly active in the slash and herbaceous material intermixed with the slash. The spacing of the rather light fuel load, shading from overstory, or the aging of the fine fuels can contribute to limiting the fire potential. Light partial cuts or thinning operations in mixed conifer stands, hardwood stands, and southern pine harvests are considered. Clear-cut operations generally produce more slash than represented here. The <3 inch material load is less than 12 tons per acre. The >3 inch material is represented by not more than 10 pieces, 4 inches in diameter along a 50-foot transect.

Fuel Model 12¹ (2.3 feet deep) Rapidly spreading fires with high intensities capable of generating firebrands can occur. When fire starts, it is generally sustained until a fuel break or change in fuels is encountered. The visual impression is dominated by slash and much of it is <3 inches in diameter. These fuels total less than 35 tons per acre and seem well distributed. Heavily thinned conifer stands, clear-cuts and medium or heavy partial cuts are represented. The >3 inch material is represented by encountering 11 pieces, 6 inches in diameter, along a 50-foot transect.

¹ When working in Fuel Model 11 or 12 with significant “red” needles attached to limbs, consider using the next heavier model. For example: Fuel Model 11 with “red” needles, use Fuel Model 12.

B-19 Fuel Model 13² (3 feet deep) Fire is generally carried by a continuous layer of slash. Large quantities of >3 inch material are present. Fires spread quickly through the fine fuels and intensity builds up as the large fuels start burning. Active flaming is sustained for long periods and a wide variety of firebrands can be generated. These contribute to spotting problems as the weather conditions become more severe. Clear-cut and heavy partial-cuts in mature and over-mature stands are depicted where the slash load is dominated by the >3 inch material. The total load may exceed 300 tons per acre, but the <3 inch fuel is generally only 10 percent of the total load. Situations where the slash still has “red” needles attached, but the total load is lighter like a Model 12, can be represented because of the earlier high intensity and faster rate of spread.

² If “red” needles are attached consider using a Fuel Model 4.

B-20 B-21 INPUT 2: Fine Dead Fuel Moisture (1-H FDFM), %

Fine Dead Fuel Moisture Content is an important input to fire behavior predictions. Fuel moisture measurements are difficult to make in the field; however, estimates can be made from measured or predicted values of dry bulb temperature and relative humidity.

Due to solar radiation differences that exist between aspect, time of year, shading, and the adiabatic difference between position on the slope, it is necessary to calculate an estimate of fuel moisture. This is necessary as the National Fire Danger Rating System (NFDRS) tables used here were developed for “worst case” conditions (summer, 1400, SW aspect, open conditions). These predictions are for fine, dead forest fuels. Heavier fuels can be estimated by other means as needed.

Temperature and humidity are predicted for a specific site (projection point) in relation to a site (site location) where dry bulb temperatures and relative humidity are measured. Since temperature and relative humidity change with elevation, it is necessary to estimate these changes between the projection point and the site location. There are tables to correct for elevation changes of 0 to 2000 feet above or below the site location, but a new site location is needed if the elevation difference between the site location and the projection point exceeds 2000 feet.

Time corrections cannot be made. Temperature and relative humidity must be obtained for the time in question.

The tables may be used to adjust the moisture of fuels in valley bottoms from conditions measured on the slopes above, but do not use weather data taken beneath a valley inversion and attempt to interpolate fuel moistures at drier sites upslope. The corrections are too large and uncertain, and you may get meaningless results.

To use the Fine Dead Fuel Moisture/Probability of Ignition Worksheet on page B-6, complete the following input/output items. Enter the fine dead fuel moisture as Output 1 on the Fine Dead Fuel Moisture/Probability of Ignition Worksheet and as Input 2 on the Fire Behavior Worksheet on page B-5.

B-22 INPUT

0 (Projection Point)—Record the number of the projection point for which a fire behavior prediction is to be made.

1 (Day Time Calculation)—Only day time calculations will be considered.

2 (Dry Bulb Temperature)—Dry bulb temperature is determined for the time period in question, either by measurement or forecast. The site location may or may not be at the projection point. Record temperature in degrees Fahrenheit.

3 (Wet Bulb Temperature)—Wet bulb temperature is determined for the time period in question, either by measurement or forecast. The site location may or may not be at the projection point. Record temperature in degrees Fahrenheit.

4 (Dew Point)—Record dew point for the time period in question.

5 (Relative Humidity)—Record relative humidity for the time period in question.

6 (Reference Fuel Moisture)—Go to Table 2 and determine the reference fuel moisture percent from the intersection of temperature and relative humidity (Inputs 2 and 5). Record as a percent.

7 (Month)—Record the appropriate month.

8 (Unshaded or Shaded)—Circle “U” if fine dead fuels ahead of the projection point are unshaded (<50% shading) from solar radiation due to cloud cover and/or canopy cover. Circle “S” if fine dead fuels ahead of the projection point are shaded (>50% shading) from solar radiation due to cloud and/or canopy cover.

B-23 9 (Time)—Record the expected time when the projection point will be used to estimate fire behavior. The temperature/RH forecast or measurement must be the same time period as the projection time period.

10 (Elevation Change)—Record the elevation difference between the location of the projection point and the temperature/RH site location and circle:

“B” if the projection point is 1000 to 2000 feet below the site location.

“L” if the projection point is 0 to 1000 feet above or below the site location.

“A” if the projection point is 1000 to 2000 feet above the site location.

If the projection point is more than 2000 feet above or below the site location, get a new forecast or reading.

11 (Aspect)—Record the aspect of the projection point location (north, south, east, or west).

12 (Slope)—Record the slope in percent (%) at the project point. (See pages B-35 and B-36 for determining percent slope.)

13 (Fuel Moisture Correction)—From Input Values 7 through 12 and the appropriate Daytime Correction Tables (Tables 3, 4, or 5) determine fuel moisture correction. Record in percent.

OUTPUT

1 (Fine Dead Fuel Moisture)—Determine the fine dead fuel moisture by adding Input Item 6 and Input Item 13. Record as a percent.

B-24 B-25 B-26 B-27 B-28 INPUT 3: Live Fuel Moisture (LFM), %

Live fuel moisture (foliage moisture) is required for Fire Behavior Models 2, 4, 5, 7 and 10. If data are unavailable for estimating live fuel moisture, the following rough estimates (Table 6) can be used. Enter the live fuel moisture for Fire Models 2, 4, 5, 7 and 10 as Input 3 on the Fire behavior Worksheet on page B-5.

B-29 INPUT 4: Midflame Windspeed (MFWS), mi/h

Midflame wind is the wind which acts directly on the flaming fire front at the level of one half the flame height. Fire generated convective winds must be ignored.

You may take wind readings directly with a handheld anemometer or other measuring device; however, the readings must be taken far enough upwind of the fire to ensure that the wind is not influenced by convective indrafts.

If you choose to use a weather forecast to estimate windspeeds, you must determine whether the forecast is for 20-foot windspeeds or midflame windspeeds.

When midflame winds are forecast, enter them directly in Input 4 of the Fire Behavior Worksheet.

If the 20-foot winds are forecast (which they usually are), the midflame windspeed must be calculated. Use the Wind Adjustment Worksheet on page B-7 and complete the following Input and Output Values.

Enter midflame windspeed as Output 1 on the Wind Adjustment Worksheet and as Input 4 on the Fire Behavior Worksheet on page B-5.

B-30 INPUT

0 (Projection Pint)—Record the number of the projection point for which a fire behavior prediction is to be made.

1 (20-foot Windspeed)—Enter the 20-foot windspeed provided in the Special Weather Forecast.

2 (Fuel Model Number)—Enter one of the 13 FBPS fuel models.

3 (Wind Sheltering)—Using Diagram 1 on page B-32, determine whether fuels are: 1) unsheltered, 2) partially sheltered, 3) fully sheltered (open) or 4) fully sheltered (closed).

4 (Wind Adjustment Factor)—Using Table 7 on page B-33, select the appropriate adjustment factor for the specific fuel and sheltering condition.

OUTPUT

1 (Midflame Windspeed)—Multiply Input 1 x Input 4 on the Wind Adjustment Worksheet for the midflame windspeed.

Remember, for basic point source predictions the wind should be blowing within + 30 degrees of upslope.

B-31 DIAGRAM 1: 20-Foot Windspeed Adjusted to Midflame Windspeed Based on Overstory

B-32 B-33 B-34 INPUT 5: Slope (SL), %

Slope Determination Process

To use the Slope Worksheet on page B-7 complete the following Input and Output Items. Enter slope as Output 1 on the Slope Worksheet and as Input 5 on the Fire Behavior Worksheet on page B-5.

INPUT

0 (Projection Point)—Record the number of the projection point for which a fire behavior prediction is to be made.

1 (Contour Interval)—Determine the contour interval from the map; i.e., 40 ft. This is the elevation change between contour lines.

2 (Map Scale)—Determine the map scale; i.e., 1:24,000. This is the number of units on the map to ground distance in the same units; i.e., one inch on the map equals 24,000 inches on the ground.

3 (Conversion Factor)—Determine how many feet are in one inch of map distance; i.e., 1 inch = 2,000 ft. To determine this, measure the distance between section lines (east to west) in inches and tenths of an inch. Divide the number of feet in a mile (5,280) by the measured map distance for the mile in inches.

Choose an area with uniform contour line separation. From the lowest point on the slope, Point A, draw a line up the slope with the contour lines intersecting at right angles, to Point B.

4 (# of Contour Intervals)—Count the number of contour interspaces crossed between Points A and B.

5 (Rise in Elevation)—Determine vertical change in elevation by counting the contour interspaces between Points A and B. Multiply by the contour interval (Input 1); i.e., 40 ft x 11 contours = 440 ft.

B-35 6 (Map Distance)—Measure horizontal distance with a ruler in inches to the tenth of an inch.

7 (Horizontal Ground Distance)—Multiply the Map Distance (Input 6) by the conversion factor (Input 3); i.e., 0.5 in x 2,000 ft/in = 1,000 ft.

OUTPUT

1 (Slope)—Calculate slope by dividing rise (Input 5) by run (Input 7) on the Slope Worksheet and multiplying by 100; i.e., rise (Input 5) divided by run (Input 7) x 100 or 440 ft divided by 1,000 ft x 100 = 44%.

RISE Vertical Distance = x 100 = % Slope RUN Horizontal Distance

This table allows the selection of conversion factors for different map scales.

B-36 INPUT 6: Effective Windspeed (EWS), mi/h

Effective windspeed is determined using the lower left quadrant of the nomogram of the fuel model being used. Enter slope (Input 5) on the horizontal axis, and the midflame windspeed (Input 4) from the Fire Behavior Worksheet on the right axis.

Interpolation between the midflame windspeed line may be necessary. Read the effective windspeed on the left side of the graph. Enter effective windspeed as Input 6 on the Fire Behavior Worksheet on page B-5.

B-37 FIRE BEHAVIOR OUTPUTS

Determine the Fire Behavior Output Items (1-9) listed below and enter them on the Fire Behavior Worksheet on page B-5.

OUTPUT 1: Rate of Spread (ROS), ch/h

Using the upper right quadrant (left vertical axis) of the nomogram and input items recorded on the Fire Behavior Worksheet, determine rate of spread. Tables 15 through 78 can also be used to approximate rate of spread.

OUTPUT 2: Heat per Unit Area (HA), Btu/sq ft

Using the upper right quadrant of the nomogram, determine heat per unit area from the lower axis.

OUTPUT 3: Fireline Intensity (FLI), Btu/ft/s

Using the upper right quadrant of the nomogram, determine fireline intensity along the curved lines.

OUTPUT 4: Flame Length (FL), ft

Using the upper right quadrant of the nomogram, determine the flame length along the curved lines. Flame length can also be approximated using Tables 15 through 78.

OUTPUT 5: Spread Distance (SD), ch

Rate of spread (Output 1) on the Fire Behavior Worksheet, multiplied by the hours in which a fire spreads at that rate, equals spread distance. Convert to map distance using the Map-Spread Worksheet as outlined on page 39.

B-38 Map-Spread Worksheet

Use the Map-Spread Worksheet on page B-8 and complete the following Input and Output Items to determine map-spread distance. Enter the map-spread distance as Output 1 on the Map-Spread Worksheet and as Output 5 on the Fire Behavior Worksheet on page B-5.

INPUT

0 (Projection Point)—Record the number of the projection point for which a fire behavior prediction is to be made.

1 (Rate of Spread)—Fire Behavior Worksheet, Output 1.

2 (Projection Time)—Hours or part of an hour in which a fire has spread.

3 (Spread Distance, ch)—Input 1 multiplied by Input 2.

4 (Spread Distance, ft)—Input 3 multiplied by 66 ft/ch.

5 (Map Scale)—Table 9 on page B-36.

6 (Conversion Factor)—Table 9.

OUTPUT

1 (Map Spread Distance)—Input 4 divided by Input 6.

B-39 OUTPUT 6 and 7: Projected Fire Perimeter (PER), ch and Fire Area (AC), ac

Use the Size Worksheet on page B-8 and complete the following Input and Output Items to determine fire perimeter and area. Enter perimeter as Output 1 on the Size Worksheet and as Output 6 on the Fire Behavior Worksheet on page B-5. Enter area as Output 2 on the Size Worksheet and as Output 7 on the Fire Behavior Worksheet on page B-5.

INPUT

0 (Projection Point)—Record the number of the projection point for which a fire behavior prediction has been made.

1 (Rate of Spread)—Output 1 from the Fire Behavior Worksheet.

2 (Effective Windspeed)—Input 6 from the Fire Behavior Worksheet.

3 (Projection Time)—The time in which a fire has spread.

4 (Spread Distance)—Input 1 multiplied by Input 3.

OUTPUT

1 (Perimeter)—From Table 10 using the spread distance (Input 4) and effective windspeed (Input 2) determine perimeter.

2 (Area)—From Table 11 using the spread distance (Input 4) and effective windspeed (Input 2) determine area (acres).

B-40 B-41 B-42 This table can be used to estimate the perimeter of a fire in chains from estimates of total spread distance (rate of spread x time) and effective windspeed. When the effective windspeed is an even number or when spread distance is not broken out, estimations can be made or interpolation may be necessary.

B-43 B-44 B-45 This table can be used to estimate the area (acres) from estimates of total spread distance (rate of spread x time) and effective windspeed. When the effective windspeed is an even number or when spread distance is not broken out, estimations can be made or interpolation may be necessary.

B-46 DIAGRAM 2—Approximate Fire Shapes for Various Effective Windspeeds

B-47 OUTPUT 8: Maximum Spotting Distance (SPOT), mi

The Spotting Worksheet is used to predict the distance a firebrand will travel from the originating torching tree. It does not apply to firebrands resulting from a running crown fire, but may be considered as a first approximation in such situations. Use the Spotting Worksheet and Nomograms 1 through 4 to determine Maximum Spotting Distance. Enter Maximum Spotting Distance on the Spotting Worksheet and as Output 8 on the Fire Behavior Worksheet on page B-5.

INPUT

1 (Torching Tree Height)—Actual height of torching tree.

2 (Torching Tree Species)—When species is not provided, select species based on crown shape and knowledge of firebrand production.

3 (Torching Tree DBH)—Diameter at breast height.

4 (Average Tree Cover Height)—Estimate average tree cover height downwind from the torching tree.

5 (Windspeed at 20-foot Height)—Use the forecasted 20- foot windspeed. When gusts are indicated, using the maximum gust would provide the worst case distance.

OUTPUT

(Maximum Spotting distance)—Enter maximum spotting distance on the Spotting Worksheet.

Convert spotting distance to map distance using the Map- Spot Worksheet as outlined on page B-49.

B-48 Map-Spot Worksheet

Use the Map-Spot Worksheet on page B-9 and complete the following Input and Output Items to determine map-spot distance. Enter the map-spot distance as Output 1 on the Map-Spot Worksheet and under Output 8 on the Fire Behavior Worksheet on page B-5.

INPUT

0 (Projection Point)—Record the number of the projection point for which a fire behavior prediction is to be made.

1 (Spotting Distance, mi)—Record the Output from the Spotting Worksheet.

2 (Spotting Distance, ft)—Multiply mile distance in Input 1 by 5,280 to obtain feet.

3 (Map Scale)—Record the map scale taken from the map being used; e.g., 1:24,000.

4 (Conversion Factor)—See Table 9 on page B-36 for correct conversion factor; e.g., 2000.

OUTPUT

1 (Map Distance Spot)—Input 2 divided by Input 4.

B-49 NOMOGRAM 1—Flame Height

From Nomogram 1, determine flame height by using DBH and torching tree species. Enter flame height in Box B on the Spotting Worksheet.

B-50 NOMOGRAM 2—Flame Duration

From Nomogram 2, determine flame duration by using DBH and tree species. Enter flame duration on the Spotting Worksheet.

B-51 NOMOGRAM 3—Ratio of Lofted Firebrand Height to Flame Height

From Nomogram 3, determine ratio of lofted firebrand height to flame height. Use flame duration and ratio of tree height to flame height as inputs. Enter ratio of lofted firebrand height to flame height in Box C on the Spotting Worksheet.

B-52 NOMOGRAM 4—Maximum Spotting Distance

On the lower right-hand edge of Nomogram 4, locate the firebrand height. Proceed vertically to the effective tree cover height. Move left horizontally until you reach the treetop windspeed; move vertically down to the bottom axis and read the maximum spotting distance. Enter the maximum spotting distance on the Spotting Worksheet.

B-53 OUTPUT 9: Probability of Ignition (PIG), %

Use Table 12 on page B-55 and the dry bulb temperature (Input 2), shading (Input 8) and the fine dead fuel moisture (Output 1) from the Fine Dead Fuel Moisture/Probability of Ignition Worksheet to determine probability of ignition.

Enter probability of ignition as Output 2 on the worksheet. Also record it as Output 9 on the Fire Behavior Worksheet on page B-5.

B-54 B-55 B-56 DIAGRAM 3—Fire Behavior Characteristics Chart (Light Fuel)

B-57 DIAGRAM 4—Fire Behavior Characteristics Chart (Heavy Fuel)

B-58 TABLE 14—Fire Suppression Interpretations¹

CAUTION: These are not guides to personal safety. Fires can be dangerous at any level of intensity. Wilson (1977) has shown that most fatalities occur in light fuels on small fires or isolated sections of large fires.

¹ Help in Making Fuel Management Decisions, 1975; Research Paper NC-112, USDA: Forest Service.

B-59 SAFETY AND FIRE BEHAVIOR

• Probably the most important aspect of predicting fire behavior is to identify potentially dangerous fireline conditions.

• Be alert to all potentially dangerous situations and communicate the danger to all affected personnel.

• Know, remember, and use:

– THE STANDARD ORDERS (Inside Cover)

– THE 18 WATCHOUT SITUATIONS (Inside Cover)

– THE FOUR COMMON DENOMINATORS OF FIRE BEHAVIOR ON TRAGEDY AND NEAR-MISS FIRES (Inside Cover)

– DOWNHILL/INDIRECT LINE CONSTRUCTION GUIDELINES (Chapter 4)

– THE 9 URBAN WILDLAND “WATCHOUTS”

– LCES (LOOK OUTS, COMMUNICATIONS, ESCAPE ROUTES, AND SAFETY ZONES)

– LOOK UP, LOOK DOWN, LOOK AROUND

B-60 FIRE ENVIRONMENT FACTORS INDICATORS

Fuel Characteristics Continuous fine fuels CARRIER! Assess Heavy loading of dead and down Ladder Fuels Tight crown spacing (<20 ft.) Special Conditions: Firebrand sources Numerous snags Preheated canopy Frost and bug kill Unusual fine fuels High dead-to-live ratio Urban/Wildland

Fuel Moisture Low RH (Dangerous <25%) Feel & Measure Low 10 hr FMC (Dangerous <6%) Drought conditions Seasonal drying

Fuel Temperature High temps (above 85 °F) Feel & Measure High % of fuels with direct sun Aspect with increasing fuel temps.

Terrain Steep slopes (>50%) Scout Chutes Saddles Narrow canyons

B-61 FIRE ENVIRONMENT FACTORS INDICATORS

Wind Surface winds above 10 mi/h Observe Lenticular clouds High, fast moving clouds Approaching cold front Cumulonimbus development Sudden calm Battling winds

Stability Clear visibility Observe Gusty winds and dust devils Cumulus clouds Castellatus clouds in the a.m. Smoke rises straight up Inversion beginning to lift Thermal belt

Fire Behavior Leaning column Watch Sheared column Well developed column Trees torching Smoldering fires picking up Small firewhirls beginning Frequent spot fires

Remember to Expect Diurnal Changes!

•RH• •Winds• •Temperature• •Stability•

• Indicators may vary in different regions and fuel types. • Ask questions in unfamiliar situations.

B-62 Tables 15 through 78—Rate of Spread and Flame Length Tables by Fuel Type and Percent Slope

NOTE: Tables 15 through 78 for ROS and FL (Output Items 1 and 4) on the Fire Behavior Worksheet reflect slope classes 0, 30, 45, 60 and 90 percent. You may use the slope class closest to the actual slope recorded (for Input Item 5) or interpolate between the slope class.

B-63 B-64 B-65 B-66 B-67 B-68 B-69 B-70 B-71 B-72 B-73 B-74 B-75 B-76 B-77 B-78 B-79 B-80 B-81 B-82 B-83 B-84 TABLE 40b: FUEL MODEL 6—30% SLOPE

B-85 B-86 B-87 B-88 B-89 B-90 B-91 B-92 B-93 B-94 B-95 B-96 B-97 B-98 B-99 B-100 B-101 B-102 B-103 B-104 B-105 B-106 B-107 B-108 B-109 B-110 B-111 B-112 B-113 B-114 B-115 B-116 B-117 B-118 B-119 B-120 B-121 B-122 B-123 B-124 United States Department of Agriculture Aids to Determining Forest Service Intermountain Fuel Models Forest and Range Experiment Station Ogden, UT 84401 For Estimating General Technical Report INT-122 April 1982 Fire Behavior

Hal E. Anderson THE AUTHOR CONTENTS

HAL E. ANDERSON has been project leader of the Fuel Page Science Research Work Unit since 1966. He joined the Introduction ...... 1 staff of Intermountain Station's Northern Forest Fire How Fuel Models are Described ...... 1 Laboratory at Missoula, Mont., in 1961. He served as Fuel Model Descriptions...... 4 project leader of the fire physics project from 1962 to Grass Group 1966. Prior to employment with the Forest Service, he Fire Behavior Fuel Model 1 ...... 4 was with the General Electric Co. and worked on thermal Fire Behavior Fuel Model 2 ...... 5 and nuclear instrumentation from 1951 to 1961. His B.S. Fire Behavior Fuel Model 3 ...... 6 degree in physics was obtained at Central Washington Shrub Group University in 1952. Fire Behavior Fuel Model 4 ...... 7 Fire Behavior Fuel Model 5 ...... 8 RESEARCH SUMMARY Fire Behavior Fuel Model 6 ...... 9 Fire Behavior Fuel Model 7 ...... 10 This report presents photographic examples, tabula- Timber Group tions, and a similarity chart to assist fire behavior offi- Fire Behavior Fuel Model 8 ...... 11 cers, fuel management specialists, and other field per- Fire Behavior Fuel Model 9 ...... 12 sonnel in selecting a fuel model appropriate for a specific Fire Behavior Fuel Model 10 ...... 13 field situation. Proper selection of a fuel model is a criti- Logging Slash Group cal step in the mathematical modeling of fire behavior Fire Behavior Fuel Model 11 ...... 14 and fire danger rating. This guide will facilitate the selec- Fire Behavior Fuel Model 12 ...... 15 tion of the proper fire behavior fuel model and will allow Fire Behavior Fuel Model 13 ...... 16 comparison with fire danger rating fuel models. Correlation of Fire Behavior Fuel Models and The 13 fire behavior fuel models are presented in 4 fuel NFDRS Fuel Models ...... 17 groups: grasslands, shrublands, timber, and slash. Each Publications Cited ...... 19 group comprises three or more fuel models; two or more Appendix: Evolution of Fuel Models ...... 20 photographs illustrate field situations relevant to each Introduction ...... 20 fuel model. The 13 fire behavior fuel models are cross- Fuels Defined ...... 20 referenced to the 20 fuel models of the National Fire How Fuels Have Been Described ...... 20 Danger Rating System by means of a similarity chart. Fire behavior fuel models and fire danger rating fuel models, along with the fire-carrying features of the model and its physical characteristics, are described in detail. United States Department of Agriculture Aids to Determining Forest Service Intermountain Fuel Models Forest and Range Experiment Station Ogden, UT 84401 For Estimating General Technical Report INT-122 April 1982 Fire Behavior

Hal E. Anderson

INTRODUCTION tion of the total load in the less than 4-inch (0.6-cm) size During the past two decades in the United States, the class decreases as we go from grasses to slash. The USDA Forest Service has progressed from a fire danger reverse is true for the 1- to 3- inch (2.5- to 7.6-cm) material. rating system comprising two fuel models (USDA 1964), to In grasses, the entire fuel load may be herbaceous nine models in 1972 (Deeming and others 1972), and to 20 material less than one fourth inch (0.6 cm), but grass may models in 1978 (Deeming and others 1977). During this include up to 25 percent material between one-fourth and time the prediction of fire behavior has become more 1 inch (0.6 and 2.5 cm) and up to 10 percent material be- valuable for controlling fire and for assessing potential tween 1 and 3 inches (2.5 cm and 7.6 cm). Each fuel fire damage to resources. A quantitative basis for rating group has a range of fuel loads for each size class, with fire danger and predicting fire behavior became possible maximum fuel load per size class approximately as with the development of mathematical fire behavior shown in figure 1. models (Rothermel 1972). The mathematical models Fuel load and depth are significant fuel properties for require descriptions of fuel properties as inputs to calcu- predicting whether a fire will be ignited, its rate of lations of fire danger indices or fire behavior potential. spread, and its intensity. The relationship of fuel load The collections of fuel properties have become known as and depth segregates the 13 fuel models into two distinc- fuel models and can be organized into four groups: grass, tive orientations, with two fuel groups in each (fig. 2). shrub, timber, and slash. Fuel models for fire danger Grasses and brush are vertically oriented fuel groups, rating have increased to 20 while fire behavior predic- which rapidly increase in depth with increasing load. tions and applications have utilized the 13 fuel models Timber litter and slash are horizontally positioned and tabulated by Rothermel (1972) and Albini (1976). This slowly increase in depth as the load is increased. Obser- report is intended to aid the user in selecting a fuel vations of the location and positioning of fuels in the model for a specific area through the use of field help one decide which fuel groups are represented. photographic illustrations. A similarity chart allows the Selection of a fuel model can be simplified if one recog- user to relate the fire behavior fuel models to the fire nizes those features that distinguish one fuel group from danger rating system fuel models. The chart also pro- another. vides a means to associate the fire danger rating system The 13 fuel models (table 1) under consideration are fuel models with a photographic representation of those presented on page 92 of Albini’s (1976) paper, “Estimat- fuel types. ing Wildfire Behavior and Effects.” Each fuel model is described by the fuel load and the ratio of surface area to volume for each size class; the depth of the fuel bed in- HOW FUEL MODELS ARE DESCRIBED volved in the fire front; and fuel moisture, including that Fuels have been classified into four groups—grasses, at which fire will not spread, called the moisture of brush, timber, and slash. The differences in fire behavior extinction. The descriptions of the fuel models include among these groups are basically related to the fuel load the total fuel load less than 3 inches (7.6 cm), dead fuel and its distribution among the fuel particle size classes. load less than one-fourth inch (0.6 cm), live fuel load of This can be illustrated by the shift in size class contain- less than one-fourth inch (0.6 cm), and herbaceous ing the maximum fraction of load when considering the material and fuel depth used to compute the fire behavior four fuel groups shown in figure 1. Notice that the frac- values given in the nomographs.

1 HERB + $ IN GRASSES

$ to 1 IN 1 to 3 IN HERB + $ IN BRUSH

$ to 1 IN 1 to 3 IN

HERB + $ IN TIMBER

$ to 1 IN 1 to 3 IN

SLASH HERB + $ IN

LOAD DISTRIBUTION BY FUEL GROUPS DISTRIBUTION LOAD $ to 1 IN 1 to 3 IN

Figure 1. — Distribution of maximum fuel load by size class for each of the four general fuel groups. Note the shift in less 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 than 4-inch (0.6-cm) and 1- to 3-inch (2.5- FRACTION OF MAXIMUM FUEL LOAD PER SIZE CLASS to 7.6-cm) material

6 FIRE BEHAVIOR FUEL MODELS

VERTICALLY GRASS ORIENTED BRUSH TIMBER 5 SLASH

3 FUEL DEPTH, FT

HORIZONTALLY ORIENTED Figure 2. — The four general fuel groups are oriented in two basic directions: ver- 0 10 20 30 40 50 tically, as in grasses and shrubs, and LOAD, TONS/ACRE horizontally, as in timber, litter, and slash.

2 Table 1. — Description of fuel models used in fire behavior as documented by Albini (1976)

______Fuel loading______Moisture of extinction Fuel model Typical fuel complex 1 hour 10 hours 100 hours Live Fuel bed depth dead fuels ------Tons/acre------Feet Percent Grass and grass-dominated 1Short grass (1 foot) 0.74 0.00 0.00 0.00 1.0 12 2Timber (grass and understory) 2.00 1.00 .50 .50 1.0 15 3Tall grass (2.5 feet) 3.01 .00 .00 .00 2.5 25

Chaparral and shrub fields 4Chaparral (6 feet) 5.01 4.01 2.00 5.01 6 0 20 5Brush (2 feet) 1.00 .50 .00 2.00 2.0 20 6Dormant brush, hardwood slash 1.50 2.50 2.00 .00 2.5 25 7Southern rough 1.13 1.87 1.50 .37 2.5 40

Timber litter 8Closed timber litter 1.50 1.00 2.50 0.00 0.2 30 9Hardwood litter 2.92 41 .15 .00 .2 25 10 Timber (litter and understory) 3.01 2.00 5.01 2.00 1.0 25

Slash 11 Light logging slash 1.50 4.51 5.51 0.00 1.0 15 12 Medium logging slash 4.01 14.03 16.53 .00 2.3 20 13 Heavy logging slash 7.01 23.04 28.05 .00 3.0 25

The criteria for choosing a fuel model includes the fact represent the day-to-day and seasonal trends in fire that the fire burns in the fuel stratum best conditioned to danger. Modifications to the fuel models are possible by support the fire. This means situations will occur where changes in live/dead ratios, moisture content, fuel loads, one fuel model represents rate of spread most accurately and drought influences by the large fuel effect on fire and another best depicts fire intensity. In other situ- danger. The 13 fuel models for fire behavior estimation ations, two fuel conditions may exist, so the spread of are for the severe period of the fire season when wildfires fire across the area must be weighted by the fraction of pose greater control problems and impact on land re- the area occupied by each fuel. Fuel models are simply sources. Fire behavior predictions must utilize on-site tools to help the user realistically estimate fire behavior. observations and short term data extrapolated from The user must maintain a flexible frame of mind and an remote measurement stations. The field use situation adaptive method of operating to totally utilize these aids. generally is one of stress and urgency. Therefore, the For this reason, the fuel models are described in terms of selection options and modifications for fuel models are both expected fire behavior and vegetation. limited to maintain a reasonably simple procedure to use The National Fire Danger Rating System (NFDRS) with fire behavior nomographs, moisture content adjust- depends upon an ordered set of weather records to ment charts, and wind reduction procedures. The NFDRS establish conditions of the day. These weather condi- fuel models are part of a computer data processing tions along with the 1978 NFDRS fuel models are used to system that presently is not suited to real time, in-the- field prediction of fire behavior.

3 FUEL MODELS DESCRIPTIONS This fuel model correlates to 1978 NFDRS fuel models Grass Group A, L, and S. Fire Behavior Fuel Model 1 Fuel model values for estimating fire behavior Fire spread is governed by the fine, very porous, and continuous herbaceous fuels that have cured or are Total fuel load, < 3-inch nearly cured. Fires are surface fires that move rapidly dead and live, tons/acre 0.74 through the cured grass and associated material. Very Dead fuel load, 4-inch, little shrub or timber is present, generally less than one- tons/acre .74 third of the area. Grasslands and savanna are represented along with Live fuel load, foliage, stubble, grass-tundra, and grass-shrub combinations that tons/acre 0 met the above area constraint. Annual and perennial Fuel bed depth, feet 1.0 grasses are included in this fuel model. Refer to photographs 1, 2, and 3 for illustrations.

Photo 1. Western annual grasses such as cheatgrass, medusahead ryegrass, and fescues.

Photo 2. Live oak savanna of the South- west on the Coronado National Forest.

Photo 3. Open pine—grasslands on the Lewis and Clark National Forest.

4 Fire Behavior Fuel Model 2 This fuel model correlates to 1978 NFDRS fuel models Fire spread is primarily through the fine herbaceous C and T. fuels, either curing or dead. These are surface fires where the herbaceous material, in addition to litter and dead- Fuel model values for estimating fire behavior down stemwood from the open shrub or timber overstory, Total fuel load, < 3-inch contribute to the fire intensity. Open shrub lands and dead and live, tons/acre 4.0 pine stands or scrub oak stands that cover one-third to two-thirds of the area may generally fit this model; such Dead fuel load, 4-inch, stands may include clumps of fuels that generate higher tons/acre 2.0 intensities and that may produce firebrands. Some Live fuel load, foliage, pinyon-juniper may be in this model. Photographs 4 and 5 tons/acre 0.5 illustrate possible fuel situations. Fuel bed depth, feet 1.0

Photo 4. Open ponderosa pine stand with annual grass understory.

Photo 5. Scattered sage within grasslands on the Payette National Forest.

5 Fire Behavior Fuel Model 3 Fuel model values for estimating fire behavior Fires in this fuel are the most intense of the grass Total fuel load, < 3-inch group and dislay high rates of spread under the influ- dead and live, tons/acre 3.0 ence of wind. Wind may drive fire into the upper heights of the grass and across standing water. Stands are tall, Dead fuel load, 4-inch, averaging about 3 feet (1 m), but considerable variation tons/acre 3.0 may occur. Approximately one-thrid of more of the stand Live fuel load, foliage, is considered dead or cured and maintains the fire. Wild tons/acre 0 or cultivated grains that have not been harvested can be considered similar to tall prairie and marshland grasses. Fuel bed depth, feet 2.5 Refer to photographs 6, 7, and 8 for examples of fuels fitting this model. Fires in the grass group fuel models exhibit some of This fuel correlates to 1978 NFDRS fuel model N. the faster rates of spread under similar weather conditions. With a windspeed of 5 mi/h (8 km/h) and a moisture content of 8 percent, representative rates of spread (ROS) are as follows:

Rate of spread Flame length Model Chains/hour Feet 1784 2356 3 104 12

As windspeed increases, model 1 will develop faster rates of spread than model 3 due to fineness of the fuels, fuel load, and depth relations.

Photo 6. Fountaingrass in Hawaii; note the dead component.

Photo 7. Meadow foxtail in Oregon prairie and meadowland.

Photo 8. Sawgrass “prairie” and “strands” in the Everglades National Park, Fla.

6 Shrub Group Fire Behavior Fuel Model 4 Fires intensity and fast-spreading fires involve the foliage and live and dead fine woody material in the crowns of a nearly continuous secondary overstory. Stands of mature shrubs, 6 or more feet tall, such as California mixed chaparral, the high pocosin along the east coast, the pinebarrens of New Jersey, or the closed jack pine stands of the north-central States are typical candidates. Besides flammable foliage, dead woody material in the stands significantly contributes to the fire intensity. Height of stands qualifying for this model depends on local conditions. A deep litter layer may also hamper suppression efforts. Photographs 9, 10, 11, and 12 depict examples fitting this fuel model. Photo 9. Mixed chaparral of southern This fuel model represents 1978 NFDRS fuel models B California; note dead fuel com- and O; fire behavior estimates are more severe than ob- ponent in branchwood. tained by models B or O.

Fuel model values for estimating fire behavior Total fuel load, < 3-inch dead and live, tons/acre 13.0 Dead fuel load, 4-inch, tons/acre 5.0 Live fuel load, foliage, tons/acre 5.0 Fuel bed depth, feet 6.0

Photo 10. Chaparral composed of manzanita and chamise near the Inaja Fire Memorial, Calif.

Photo 11. Pocosin shrub field composed of species like fetterbush, gallberry, and the bays.

Photo 12. High shrub southern rough with quantity of dead limbwood.

7 Fire Behavior Fuel Model 5 Fuel model values for estimating fire behavior Fire is generally carried in the surface fuels that are Total fuel load, < 3-inch made up of litter cast by the shrubs and the grasses or dead and live, tons/acre 3.5 forbs in the understory. The fires are generally not very intense because surface fuel loads are light, the shrubs Dead fuel load, 4-inch, are young with little dead material, and the foliage con- tons/acre 1.0 tains little volatile material. Usually shrubs are short and Live fuel load, foliage, almost totally cover the area. Young, green stands with tons/acre 2.0 no dead wood would qualify: laurel, vine maple, alder, or even chaparral, manzanita, or chamise. Fuel bed depth, feet 2.0 No 1978 NFDRS fuel model is represented, but model 5 can be considered as a second choice for NFDRS model D or as a third choice for NFDRS model T. Photographs 13 and 14 show field examples of this type. Young green stands may be up to 6 feet (2 m) high but have poor burning properties because of live vegetation.

Photo 13. Green, low shrub fields within timber stands or without overstory are typical. Example is Douglas-fir–snowberry habitat type.

Photo 14. Regeneration shrublands after fire or other disturbances have a large green fuel component, Sundance Fire, Pack River Area, Idaho.

8 Fire Behavior Fuel Model 6 Fires carry through the shrub layer where the foliage is more flammable than fuel model 5, but this requires moderate winds, greater than 8 mi/h (13 km/h) at midflame height. Fire will drop to the ground at low wind speeds or at openings in the stand. The shrubs are older, but not as tall as shrub types of model 4, nor do they contain as much fuel as model 4. A broad range of shrub conditions is covered by this model. Fuel situations to be considered include intermediate stands of chamise, chaparral, oak brush, low pocosin, Alaskan spruce taiga, and shrub tundra. Even hardwood slash that has cured can be considered. Pinyon-juniper shrublands may be represented but may overpredict rate of spread except at Photo 15. Pinion-juniper with sagebrush high winds, like 20 mi/h (32 km/h) at the 20-foot level. near Ely, Nev.; understory The 1978 NFDRS fuel models F and Q are represented mainly sage with some grass by this fuel model. It can be considered a second choice intermixed. for models T and D and a third choice for model S. Photo- graphs 15, 16, 17, and 18 show situations encompassed by this fuel model.

Fuel model values for estimating fire behavior Total fuel load, < 3-inch dead and live, tons/acre 6.0 Dead fuel load, 4-inch, tons/acre 1.5 Live fuel load, foliage, tons/acre 0

Fuel bed depth, feet 2.5 Photo 16. Southern harwood shrub with pine slash residues.

Photo 17. Low pocosin shrub field in the south.

Photo 18. Frost-killed Gambel Oak foliage, less than 4 feet in height, in Colorado.

9 Fire Behavior Fuel Model 7 Fuel model values for estimating fire behavior Fires burn through the surface and shrub strata with Total fuel load, < 3-inch equal ease and can occur at higher dead fuel moisture dead and live, tons/acre 4.9 contents because of the flammability of live foliage and other live material. Stands of shrubs are generally be- Dead fuel load, 4-inch, tween 2 and 6 feet (0.6 and 1.8 m) high. Palmetto-gallberry tons/acre 1.1 understory-pine overstory sites are typical and low Live fuel load, foliage, pocosins may be represented. Black spruce-shrub com- tons/acre 0.4 binations in Alaska may also be represented. This fuel model correlates with 1978 NFDRS model D Fuel bed depth, feet 2.5 and can be a second choice for model Q. Photographs 19, 20, and 21 depict field situations for this model. The shrub group of fuel models has a wide range of fire intensities and rates of spread. With winds of 5 mi/h (8 km/h), fuel moisture content of 8 percent, and a live fuel moisture content of 100 percent, the models have the values:

Rate of spread Flame length Model Chains/hour Feet 47519 5184 6326 7205

Photo 19. Southern rough with light to moderate palmetto understory.

Photo 20. Southern rough with moderate to heavy palmetto-gallberry and other species.

Photo 21. Slash pine with gallberry, bay, and other species of understory rough.

10 Timber Group Fuel model values for estimating fire behavior Fire Behavior Fuel Model 8 Total fuel load, < 3-inch Slow-burning ground fires with low flame lengths are dead and live, tons/acre 5.0 generally the case, although the fire may encounter an occasional “jackpot” or heavy fuel concentration that Dead fuel load, 4-inch, can flare up. Only under severe weather conditions in- tons/acre 1.5 volving high temperatures, low humidities, and high Live fuel load, foliage, winds do the fuels pose fire hazards. Closed canopy tons/acre 0 stands of short-needle conifers or hardwoods that have leafed out support fire in the compact litter layer. This Fuel bed depth, feet 0.2 layer is mainly needles, leaves, and occasionally twigs because little undergrowth is present in the stand. Repre- sentative conifer types are white pine, and lodgepole pine, spruce, fir, and larch. This model can be used for 1978 NFDRS fuel models H and R. Photographs 22, 23, and 24 illustrate the situations representative of this fuel.

Photo 22. Surface litter fuels in western hemlock stands of Oregon and Washington.

Photo 23. Understory of inland Douglas- fir has little fuel here to add to dead-down litter load.

Photo 24. Closed stand of birch-aspen with leaf litter compacted.

11 Fire Behavior Fuel Model 9 NFDRS fuel models E, P, and U are represented by this Fires run through the surface litter faster than model 8 model. It is also a second choice for models C and S. and have longer flame height. Both long-needle conifer Some of the possible field situations fitting this model stands and hardwood stands, especially the oak-hickory are shown in photographs 25, 26, and 27. types, are typical. Fall fires in hardwoods are predictable, but high winds will actually cause higher rates of spread Fuel model values for estimating fire behavior than predicted because of spotting caused by rolling and Total fuel load, < 3-inch blowing leaves. Closed stands of long-needled pine like dead and live, tons/acre 3.5 ponderosa, Jeffrey, and red pines, or southern pine plantations are grouped in this model. Concentrations of Dead fuel load, 4-inch, dead-down woody material will contribute to possible tons/acre 2.9 torching out of trees, spotting, and crowning. Live fuel load, foliage, tons/acre 0 Fuel bed depth, feet 0.2

Photo 25. Western Oregon white oak fall litter; wind tumbled leaves may cause short-range spotting that may increase ROS above the predicted value.

Photo 26. Loose hardwood litter under stands of oak, hickory, maple and other hardwood species of the East.

Photo 27. Long-needle forest floor litter in ponderosa pine stand near Alberton, Mont.

12 Fire Behavior Fuel Model 10 The fire intensities and spread rates of these timber The fires burn in the surface and ground fuels with litter fuel models are indicated by the following values greater fire intensity than the other timber litter models. when the dead fuel moisture content is 8 percent, live Dead-down fuels include greater quantities of 3-inch fuel moisture is 100 percent, and the effective windspeed (7.6-cm) or larger Iimbwood resulting from overmaturity or at midflame height is 5 mi/h (8 km/h): natural events that create a large load of dead material on the forest floor. Crowning out, spotting, and torching Rate of spread Flame length of individual trees are more frequent in this fuel situation, Model Chains/hour Feet leading to potential fire control difficulties. Any forest 8 1.6 1.0 type may be considered if heavy down material is pres- 9 7.5 2.6 ent; examples are insect- or disease-ridden stands, wind- 10 7.9 4.8 thrown stands, overmature situations with deadfall, and aged light thinning or partial-cut slash. Fires such as above in model 10 are at the upper limit The 1978 NFDRS fuel model G is represented and is of control by direct attack. More wind or drier conditions depicted in photographs 28, 29, and 30. could lead to an escaped fire. Fuel model values for estimating fire behavior Total fuel load, < 3-inch dead and live, tons/acre 12.0 Dead fuel load, 4-inch, tons/acre 3.0 Live fuel load, foliage, tons/acre 2.0 Fuel bed depth, feet 1.0

Photo 28. Old-growth Douglas-fir with heavy ground fuels.

Photo 29. Mixed conifer stand with dead- down woody fuels.

Photo 30. Spruce habitat type where succession or natural disturbance can produce a heavy downed fuel load.

13 Logging Slash Group The 1978 NFDRS fuel model K is represented by this Fire Behavior Fuel Model 11 model and field examples are shown in photographs 31, Fires are fairly active in the slash and herbaceous 32, and 33. material intermixed with the slash. The spacing of the rather light fuel load, shading from overstory, or the Fuel model values for estimating fire behavior aging of the fine fuels can contribute to limiting the fire Total fuel load, < 3-inch potential. Light partial cuts or thinning operations in dead and live, tons/acre 11.5 mixed conifer stands, hardwood stands, and southern pine harvests are considered. Clearcut operations gen- Dead fuel load, 4-inch, erally produce more slash than represented here. The tons/acre 1.5 less-than-3-inch (7.6-cm) material load is less than 12 tons Live fuel load, foliage, per acre (5.4 t/ha). The greater-than-3-inch (7.6-cm) is rep- tons/acre 0 resented by not more than 10 pieces, 4 inches (10.2 cm) in diameter, along a 50-foot (15-m) transect. Fuel bed depth, feet 1.0

Photo 31. Slash residues left after sky- line logging in western Montana.

Photo 32. Mixed conifer partial cut slash residues may be similar to closed timber with down woody fuels.

Photo 33. Light logging residues with patchy distribution seldom can develop high intensities.

14 Fire Behavior Fuel Model 12 This model depicts 1978 NFDRS model J and may Rapidly spreading fires with high intensities capable of overrate slash areas when the needles have dropped and generating firebrands can occur. When fire starts, it is the limbwood has settled. However, in areas where limb- generally sustained until a fuel break or change in fuels wood breakup and general weathering have started, the is encountered. The visual impression is dominated by fire potential can increase. Field situations are presented slash and much of it is less than 3 inches (7.6 cm) in in photographs 34, 35, and 36. diameter. The fuels total less than 35 tons per acre (15.6 t/ha) and seem well distributed. Heavily thinned Fuel model values for estimating fire behavior conifer stands, clearcuts, and medium or heavy partial Total fuel load, < 3-inch cuts are represented. The material larger than 3 inches dead and live, tons/acre 34.6 (7.6 cm) is represented by encountering 11 pieces, 6 inches (15.2 cm) in diameter, along a 50-foot (15-m) Dead fuel load, 4-inch, transect. tons/acre 4.0 Live fuel load, foliage, tons/acre 0 Fuel bed depth, feet 2.3

Photo 34. Ponderosa pine clearcut east of Cascade mountain range in Oregon and Washington.

Photo 35. Cedar-hemlock partial cut in northern Idaho, Region 1, USFS.

Photo 36. Lodgepole pine thinning slash on Lewis and Clark National Forest. Red slash condition increases classification from light to medium.

15 Fire Behavior Fuel Model 13 Fuel model values for estimating fire behavior Fire is generally carried across the area by a continu- Total fuel load, < 3-inch ous layer of slash. Large quantities of material larger dead and live, tons/acre 58.1 than 3 inches (7.6 cm) are present. Fires spread quickly through the fine fuels and intensity builds up more slowly Dead fuel load, 4-inch, as the large fuels start burning. Active flaming is sus- tons/acre 7.0 tained for long periods and a wide variety of firebrands Live fuel load, foliage, can be generated. These contribute to spotting problems tons/acre 0 as the weather conditions become more severe. Clear- cuts and heavy partial-cuts in mature and overmature Fuel bed depth, feet 3.0 stands are depicted where the slash load is dominated by the greater-than-3-inch (7.6-cm) diameter material. The For other slash situations: total load may exceed 200 tons per acre (89.2 t/ha) but Hardwood slash ...... Model 6 fuel less than 3 inches (7.6-cm) is generally only 10 per- Heavy “red” slash ...... Model 4 cent of the total load. Situations where the slash still has Overgrown slash ...... Model 10 “red” needles attached but the total load is lighter, more Southern pine clearcut slash ...... Model 12 like model 12, can be represented because of the earlier The comparative rates of spread and flame lengths for high intensity and quicker area involvement. the slash models at 8 percent dead fuel moisture content The 1978 NFDRS fuel model I is represented and is and a 5 mi/h (8 km/h) midflame wind are: illustrated in photographs 37 and 38 Areas most commonly fitting this model are old-growth stands west of Rate of spread Flame length the Cascade and Sierra Nevada Mountains. More effi- Model Chains/hour Feet cient utilization standards are decreasing the amount of large material left in the field. 11 6.0 3.5 12 13.0 8.0 13 13.5 10.5

Photo 37. West coast Douglas-fir clearcut, quality of cull high.

Photo 38. High productivity of cedar-fir stand can result in large quantities of slash with high fire potential.

16 CORRELATION OF FIRE BEHAVIOR FUEL MODELS climate 3 was used, with the live herbaceous fuels 99.7 AND NFDRS FUEL MODELS percent cured and a wind of 20 mi/h (32 km/h) at the 20- The following section, which correlates fuel models foot (6.1- used for fire behavior with those used for fire danger rating, should help fire behavior officers (FBO’s), re- searchers, or other concerned personnel understand the relationship of the two sets of fuel models. For initial fire behavior estimates, the fuel model used for fire danger rating can be cross referenced to a fire behavior fuel model suitable for the general area of interest. It also provides useful background about the character of each fuel model so specific selections can be made where vegetation varies considerably. Combining this information with the photographic representations of each of the 13 fuel models presents the concept that a single fuel model may represent several vegetative groups. It is important that one maintain an open, flexible impression of fuel models so as to recognize those vegetative groups with common fire-carrying characteristics. The correlation with the 1978 NFDRS fuel models allows conversion from fire danger trend measurements to field-oriented prediction of fire behavior. The great variety of fuel, weather, and site conditions that exist in the field means the user of fuel models and fire behavior interpretation methods must make observations and adjust his predictions accordingly. Calibration of the fire behavior outputs for the selected fuel model can allow more precise estimation of actual conditions. This has been practiced in the field by instructors and trainees of the Fire Behavior Officer’s (FBO) School, S-590, and has provided a greater degree of flexibility in application. The fuel models shown in figure 3 were aIined according to the fuel layer controlling the rate of fire spread. Some second and third choices are indicated for situations where fire spread may be governed by two or more fuel layers, depending on distribution and moisture content. From the four climates used in the 1978 NFDRS,

17 PHYSICAL DESCRIPTION SIMILARITY CHART OF NFDRS AND FBO FUEL MODELS

NFDRS MODELS REALINED TO FUELS CONTROLLING SPREAD UNDER SEVERE BURNING CONDITIONS

NFDRS FIRE BEHAVIOR FUEL MODELS FUEL MODELS 12 3 45 67891011 12 13

A W. ANNUALS X

L W. PERENNIAL X

S TUNDRA X 3rd 2nd

C OPEN PINE X 2nd W/GRASS T SAGEBRUSH X 3rd 2nd W/GRASS N SAWGRASS X

B MATURE BRUSH X (6FT) O HIGH POCOSIN X

F INTER. BRUSH 2nd X SHRUB GRASS Q ALASKA BLACK X 2nd SPRUCE D SOUTHERN ROUGH 2nd X

H SRT- NDL CLSD. X NORMAL DEAD R HRWD. LITTER X (SUMMER) U W. LONG- NDL X PINE P SOUTH, LONG- NDL X PINE E HRWD. LITTER X (FALL) G SRT- NDL CLSD. X HEAVY DEAD K LIGHT SLASH X

J MED. SLASH X SLASH TIMBER I HEAVY SLASH X

GRASS SHRUB TIMBER SLASH

Figure 3. — Similarity chart to aline physical descriptions of fire danger rating fuel models with fire behavior fuel models.

18 PUBLICATIONS CITED Kessell, S. R. Albini, Frank A. 1976. Wildland inventories and fire model gradient 1976. Estimating wildfire behavior and effects. USDA analysis in Glacier National Park. In Proc. Tall For. Serv. Gen. Tech. Rep. INT-30, 92 p. lntermt. For. Timbers Fire Ecol. Conf. and Fire and Land Manage. and Range Exp. Stn., Ogden, Utah. Symp. No. 14, 1974. p. 115-162. Tall Timber Res. Stn., Barrows, J. S. Tallahassee, Fla. 1951. Fire behavior in northern Rocky Mountain Kessell, S. R. forests. USDA For. Serv., North. Rocky Mt. For. and 1977. Gradient modeling: a new approach to fire model- Range Exp. Stn., Pap. 29, 123 p. ing and resource management. In Ecosystem model- Bates, Carlos G. ing in theory and practice: an introduction with case 1923. The transact of a mountain valley. Ecology 4(1): histories. p. 575-605. C.A.S. Hall and J. Day, Jr., eds. 54-62. Wiley & Sons, New York. Bevins, C. D. Kessell, S. R., P. J. Cattelino, and M. W. Potter. 1976. Fire modeling for natural fuel situations in 1977. A fire behavior information integration system for Glacier National Park. In Proc., First Conf. on Sci. southern California chaparral. In Proc. of the Sym- Res. in the Natl. Parks [New Orleans, La., Nov. 1976]. posium on the Environmental Consequences of Fire p. 23. and Fuel Management in Mediterranean Eco- Deeming, John E., and James K. Brown. systems. p. 354-360. USDA For. Serv. Gen. Tech. 1975. Fuel models in the National Fire-Danger Rating Rep. WO-3. Washington, D.C. System. J. For. 73:347-350. Kessell, Stephen R., and Peter J. Cattelino. Deeming, John E., Robert E. Burgan, and Jack D. Cohen. 1978. Evaluation of a fire behavior information integra- 1977. The National Fire-Danger Rating System—1978. tion system for southern California chaparral wild- USDA For. Serv. Gen. Tech. Rep. INT-39, 63 p. lands Environ. Manage. 2:135-159. lntermt. For. and Range Exp. Stn., Ogden, Utah. Küchler, A. W. Deeming, John E., J. W. Lancaster, M. A. Fosberg, R. W. 1967. Vegetation mapping. 472 p. The Ronald Press Furman, and M. J. Schroeder. Co., New York. 1972. The National Fire-Danger Rating System. USDA PhiIpot, C. W. For. Serv. Res. Pap. RM-184, 165 p. Rocky Mt. For. 1977. Vegetation features as determinants of fire fre- and Range Exp. Stn., Fort Collins, Colo. quency and intensity. In Proc. of the Symposium on Dubois, Coert. the Environmental Consequences of Fire and Fuel 1914. Systematic fire protection in the California Management in Mediterranean Ecosystems. p. 12-16. forests. 99 p. USDA For. Serv., Washington, D.C. USDA For. Serv. Gen. Tech Rep. WO-3. Washington, Fahnestock, George R. D.C. 1970. Two keys for appraising forest fire fuels. USDA Rothermel, Richard C. For. Serv. Res. Pap. PNW-99, 26 p. Pac. Southwest 1972. A mathematical model for fire spread predictions For. and Range Exp. Stn., Berkeley, Calif. in wildland fuels. USDA For. Serv. Res. Pap. INT-115, Hornby, L. G. 40 p. lntermt. For. and Range Exp. Stn., Ogden, Utah. 1935. Fuel type mapping in Region One. J. For. 33(1): Rothermel, Richard C., and Charles W. Philpot. 67-72. 1973. Fire in wildland management: predicting changes Hough, W. A., and F. A. Albini. in chaparral flammability. J. For. 71(10):640-643. 1976. Predicting fire behavior in palmetto-gallberry fuel Show, S. B., and E. I. Kotok. complexes. USDA For. Serv. Res. Pap. SE-174, 44 p. 1929. Cover type and fire control in the National For- Southeast. For. Exp. Stn., Asheville, N.C. ests of northern California. USDA For. Serv. Bull. Jemison, G. M., and J. J. Keetch. 1495, 35 p. Washington, D.C. 1942. Rate of spread of fire and its resistance to con- Sparhawk, W. N. trol in the fuel types in eastern mountain forests. 1925. The use of liability ratings in planning forest fire USDA For. Serv., Appalachian For. Stn., Tech. protection. J. Agric. Res. 30(8):693-762. Note 52. Asheville, N.C. U.S. Department of Agriculture, Forest Service. 1964. Handbook on National Fire-Danger Rating Sys- tem. USDA For. Serv. Handb. FSH 5109.11. Washing- ton, D.C.

19 APPENDIX: EVOLUTION OF FUEL MODELS rate of spread will be. Loading and its vertical arrange- Introduction ment will influence flame size and the ability of a fire to More than 64 years ago, foresters in the United States “torch out” the overstory. With the proper horizontal con- were concerned about fire danger and were attempting to tinuity in the overstory, the fire may develop into a crown develop methods to assess the hazard (Dubois 1914). The fire. Low fuel moisture content has a significant impact “inflammability” of a situation depended on four ele- upon fire behavior affecting ignition, spread, and inten- ments: (1) amount of ground fuels; (2) ease of ignition; sity; with high winds it can lead to extreme fire behavior. (3) dryness of the cover; and (4) slope. Three fuel types Certain elements of the fuel’s chemical content, such as were considered: grass, brush, and timber. In 1978, we volatile oils and waxes, aid fire spread, even when are still concerned about fire danger and fire behavior. moisture contents are high. Others, like mineral content, Through the use of mathematical fire behavior models may reduce intensity when moisture contents are low. (Rothermel 1972) and fire danger ratings (Deeming and High fuel loads in the fine fuel size classes with low fuel others 1977), we can evaluate how fire danger changes moisture contents and high volatile oil contents will con- with weather, fuels, and slope. In addition, the fire be- tribute to rapid rates of spread and high fire line intensi- havior officer on a fire can estimate the fire behavior for ties, making initial attack and suppression difficult. the next burning period if he can define the fuels (Albini 1976). Dubois grouped fuels as grass, brush, and timber, and these general groupings are still used with the addition of slash. Several fuel types or fuel models are recog- How Fuels Have Been Described nized within each group. For fire danger rating, we have In the expression of fire danger presented by Dubois gone from two fuel models (USDA Forest Service 1964) to (1914), the fuel types of grass, brush, and timber were nine in 1972 (Deeming and others 1972) and 20 in 1978 defined, utilizing three causes—amount of fuel on the (Deeming and others 1977). Research efforts to assist the ground, lack of moisture in the cover, and slope—and fire behavior officer have utilized the 13 fuel models tabu- two effects—ease of ignition and rate of fire growth or lated by Rothermel (1972) and Albini (1976). spread. As Dubois pointed out, however, not enough study had been made of rate of spread to effectively describe differences among the fuel types. Sparhawk Fuels Defined (1925) conducted an extensive study of fire size as a func- Fuels are made up of the various components of vege- tion of elapsed time from discovery to initial attack by tation, live and dead, that occur on a site. The type and broad forest cover types Twenty-one fire regions for the quantity will depend upon the soil, climate, geographic western United States and the Lake States were defined features, and the fire history of the site. To a large extent, and up to seven forest types selected for each region. potential evapotranspiration and annual precipitation These forest types basically were grass, brush, timber, combinations with altitude and latitude changes can de- and slash descriptions. The ranking of area growth rates scribe the expected vegetation and have been used for by type showed the highest growth rates occurred in vegetation maps (Küchler 1967) An adequate description grasses and brush types, followed by slash and open of the fuels on a site requires identifying the fuel com- timber situations and concluding with low growth rates ponents that may exist. These components include the in closed timber types. Sparhawk made the following litter and duff layers, the dead-down woody material, comment regarding his data: grasses and forbs, shrubs, regeneration and timber. Vari- Rating obtained, therefore, will represent averages ous combinations of these components define the major of fairly broad application, but may now show what fuel groups of grass, shrub, timber and slash. Certain can be expected on individual units. These factors features of each fuel component or the lack of it contrib- can be allowed for only when the fire records and utes to the description of the fuels in terms suitable to the inventory of our forest resources include infor- define a fuel model. For each fuel component certain mation concerning them. characteristics must be quantified and evaluated to Show and Kotok (1929) reported on a preliminary study select a fuel model for estimating fire behavior. The most of forest cover as related to fire control. Study of the nine important characteristics for each component are: major cover types in northern California showed definite 1. Fuel loading by size classes differences between them regarding fire danger, ignition 2. Mean size and shape of each size class risk, rate of spread, and type of fire and several other fire 3. Compactness or bulk density control subjects. They did not attempt to complete 4. Horizontal continuity analysis proposed by Sparhawk because the variability of 5. Vertical arrangement individual fires was so great and the classification of 6. Moisture content type and hazard classes was so incomplete. However, 7. Chemical content, ash, and volatiles. their nine cover types fit a broader classification of: Each of the above characteristics contributes to one or 1. Woodlands and grasslands more fire behavior properties. Fuel loading, size class 2. Chaparral and brush fields distribution of the load, and its arrangement (compact- 3. Timber cover types: ness or bulk density) govern whether an ignition will a. western yellow pine and mixed conifer result in a sustaining fire. Horizontal continuity influ- b. Douglas-fir ences whether a fire will spread or not and how steady c. sugar pine-fir and fir.

20 These cover types and their classification express the The variation of ROS rating is due not so much to fuels broad groupings of grass-dominated, brush-dominated, alone as to the combination of fuels, climate, season, and timber-residue-dominated fuel groups. Timber resi- and local weather. These additional factors influence the dues can be either naturally occurring dead woody or quantity of live fuel and the moisture content of the dead activity-caused slash. In terms of fire behavior, these fuels. Other agencies such as the BLM have utilized the cover types could be characterized as follows: approach for each management area and have a set of Crown fires (occur in secondary or primary overstory)— ratings for six areas. chaparral and brush types. Fuels became a consideration in fire danger ratings in Surface fires (occurs in surface litter, dead down the 1950’s; in 1958 an effort was made to unify the eight woody, and herbaceous material)—woodlands and fire danger rating systems into one national system grasslands; western yellow pine and mixed conifer; (Deeming and others 1972). Two fuel conditions were Douglas-fir. considered—fuels sheltered under a timber cover and Ground fires (occur in litter, duff, and subsurface or- fuels in an open, exposed site. A relative spread index ganic material) sugar pine-fir; fir type. was developed and brought into general use by 1965. This work showed the complexity of establishing hour Review of the approach and the expressed need for the control needs and contributes to continued efforts to ignition, risk, and energy indexes resulted in a research describe types in terms of fire growth and control diffi- effort that yielded the 1972 National Fire Danger Rating culty. System (NFDRS). Fuels could be considered in greater Hornby (1935) developed a fuel classification system detail because a mathematical fire spread model had that formalized the description of rate of spread and been developed by Rothermel (1972). Nine specific de- resistance to control into classes of low, medium, high, scriptions of fuel properties, called fuel models, were and extreme. For the Northern Rocky Mountains, the developed for the NFDRS (Deeming and Brown 1975). standard timber types relative ranking was similar to that Fahnestock (1970), in his guide “Two keys for appraising of Show and Kotok as well as work in Colorado by Bates forest fire fuels,” was among the first to use the Rother- (1923) and described by Hornby (1935): mel fire spread model. The keys provide tools for recog- 1. Brush—grass nizing the differences in fuel types and identifying the 2. Ponderosa pine relative fire hazard potential in terms of rate of spread or 3. Larch—fir crowning. To use the keys, one must describe physical 4. Douglas-fir and lodgepole pine fuel properties in Fahnestock’s terms: fine, small, 5. White pine and Iodgepole pine medium for size classes and sparse, open, dense, fluffy, 6. Subalpine fir or thatched for compactness or combination of loading 7. White fir and spruce. and depth. By keying on the fuel properties of the site, Classification of these fuels was accomplished by utiliz- one of the 36 rate-of-spread ratings or one of the 24 ing 90 men experienced in fire hazard. A total of 42 rat- crowning-potential ratings can be selected. ings were assigned to typical fuels in Region 1. Hornby Fahnestock interpreted the size class descriptions for noted that a weakness of the system was the use of each fuel stratum according to the physical dimensions estimates rather than extensive accurate measurements, and timelags associated with the 1964 NFDRS. Timelag but until enough years of data had been collected on is the time necessary for a fuel size class to change 63 contributing influences, some procedures for rating fuels percent of the total expected change. These same de- were needed. Adaptations of Hornby’s approach have scriptions were used when fuel models were developed been utilized in the eastern United States (Jemison and to represent broad vegetative types of grasslands, brush- Keetch 1942) and modified later in the West (Barrows fields, timbered land, and slash. Within each fuel model, 1951). Most Forest Service regions utilized some version the load was distributed by size or timelag classes, cor- of the Hornby rating method but generally assigned rate related with groupings of foliage and twigs, branchwood, of spread values unique to their area, thereby reducing and tree or shrub material as follows: comparability. This is illustrated by a sampling of the number of ratings used by various regions and some of Size, diameter Timelag the variation that existed for rate of spread (ROS) Inch Hours classes. < 4 1 No. of ROS 4 to 1 10 Region Year ratings (chains/hour) 1 to 3 100 > 3 1,00011 Region 1 1969 234 High (51) Region 1 1974 4 High (25) 1Large fuels or layers slow to respond are recognized in the fuel Region 2 1972 59 High (25) models available in the 1978 NFDRS. Region 3 1970 11 Region 4 1972 48 High (30) The initial fuel models were documented by Rothermel Eastern 1966 15 (1972) and these 13 models were reduced to 9 models for Region 5 1973 17 the 1972 NFDRS (Deeming and others 1972). The original Region 6 1972 16 High (25) examples 9 fuel models, except for one, have been retained in the Region 8 1975 High (>10) 1978 NFDRS and supplemented by 11 others to accom- Region 9 1970 10 21 modate differences across the country. For fire behavior officer training, the 13 fuel models initially presented by Rothermel (1972) and Albini (1976) are currently being used. The 13 models encompass those of the 1972 NFDRS and can be correlated to the 1978 NFDRS models. At the present time, the fuel models have the broadest application, while other research is providing fuel models for specific applications (Kessell 1976, 1977; Bevins 1976; Kessell, Cattelino, and Potter 1977; Philpot 1977; Hough and Albini 1978; Rothermel and Philpot 1973).

Anderson, Hal E. 1982. Aids to determining fuel models for estimating fire behavior. USDA For. Serv. Gen. Tech. Rep. INT-122, 22p. lntermt. For. and Range Exp. Stn., Ogden, Utah 84401.

Presents photographs of wildland vegetation appropriate for the 13 fuel models used in mathematical models of fire behavior. Fuel model descriptions include fire behavior associated with each fuel and its physical characteristics. A similarity chart cross-references the 13 fire behavior fuel models to the 20 fuel models used in the National Fire Danger Rating System.

Keywords: forest fuels, modeling, fire behavior The Intermountain Station, headquartered in Ogden Utah, is one of eight regional experiment stations charged with providing scientific knowledge to help resource managers meet human needs and protect forest and range ecosystems. The Intermountain Station includes the States of Montana, Idaho, Utah, Nevada, and western Wyoming. About 273 million acres, or 85 percent, of the land area in the Station territory are classified as forest and rangeland. These lands include grasslands, deserts, shrublands, alpine areas, and well-stocked forests. They supply fiber for forest in- dustries; minerals for energy and industrial development; and water for domestic and industrial consumption. They also provide recreation opportunities for millions of visitors each year. Field programs and research work units of the Station are maintained in:

Boise, Idaho

Bozeman, Montana (in cooperation with Montana State University)

Logan, Utah (in cooperation with Utah State University)

Missoula, Montana (in cooperation with the University of Montana)

Moscow, Idaho (in cooperation with the Univer- sity of Idaho)

Provo, Utah (in cooperation with Brigham Young University)

Reno, Nevada (in cooperation with the University of Nevada)