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Home , Cascade Volcanoes, Lava dome, Mount Baker, Mount Unzen, Volcano

INTRODUCTION TO VOLCANOES 1

Introduction

Active volcanoes dominate the sky- short-lived, volcanoes dot the - line in many parts of the Pacific scape in southwest and Northwest. These familiar -clad northwest , the youngest of peaks are part of a 1,000 mile-long them a few thousand years old. These chain of volcanoes, the Cascade individual volcanoes probably won’t , which extends from erupt again; rather, new volcanoes northern to southern will form among them and add to the . This guide focuses broad regional volcanic fields that on the five in Washington State lie among the major volcanoes from (, Peak, Mount southward. Rainier, Mount St. Helens, and ) and in northern and volcanoes — Oregon that are long-lived volcanoes, a dangerous combination having erupted recurrently for hun- Large parts of Washington’s Cascade dreds of thousands of years. All of volcanoes are covered with perma- these volcanoes have erupted in the nent snow and that pose a special recent geologic past and will erupt hazard during volcanic eruptions. again in the future. In 1980 Mount Even small eruptions can melt a St. Helens vividly demonstrated the sufficient amount of snow and ice power that can to trigger that can travel tens unleash when they do erupt. of miles beyond the flanks of the into populated valleys. For Frequency of eruptions years after an eruption, of in the deposits can cause increased sedi- Seven major, long-lived volcanoes ment deposition that clogs channels, in the Cascades, including three disrupts aquatic ecosystems, and in Washington and Mount Hood in worsens flooding. northern Oregon, have erupted since early pioneers arrived in the region. Note to Media Many of those eruptions would have This guidebook supplies back- caused considerable property - ground information about volcano age, and potentially loss of life, had hazards and an overview of the they happened today. Based on the notification process used to send frequencies of eruptions during the volcano alerts to emergency and past 4,000 years, we expect that sev- land managers, the media, emer- eral eruptions will occur per century. gency broadcasters, and the public. Each eruptive episode is likely to last It includes background information months or years to perhaps a decade about expectable at or more. In addition to the major vol- Washington volcanoes, maps show- canoes, hundreds of small, typically

ISSUE UPDATE: JUNE 2010 2 MEDIA GUIDEBOOK FOR NATURAL HAZARDS IN WASHINGTON

ing areas most susceptible to these Signs of unrest and eruption hazards, a volcano warning flow trigger alerts chart that shows how information Scientists cannot forecast when a is sent to emergency management volcano will become active, although and local media, and a list of pub- once signs of unrest are noted and lished resources and specialists sufficient measurements are made, who can provide credible volcano they may be able to estimate the like- information. lihood of an eruption and sometimes its size and character. Volcanoes typ- Communicating hazards ically show signs of unrest, such as information increased , emission of The US Geological Survey’s Cascades volcanic gases, and subtle ground Volcano (USGS-CVO) movement, days to months in issues alert-level notifications and advance of an eruption. information statements, and, when- activity is often the first indicator of ever possible, specific forecasts volcanic unrest. The USGS, in coor- regarding eruptions and their poten- dination with the tial impacts. This process includes Seismic Network (PNSN) at the color codes for aviation hazards. University of Washington, monitors Volcano alert levels and the avia- seismic unrest in the Washington tion color codes are described in the Cascades. Volcano Alert Notification System section (refer to Notification System Earthquake swarms at tab section). Scientists notify emer- Cascade volcanoes gency-management officials and the Swarms of small earthquakes that go media using the process described on for up to several days are common in the Volcano Warning Flow Chart features at many volcanoes. The vast (see Flow Chart tab). At all times, the majority of these earthquake swarms USGS-CVO provides information do not lead directly to eruptive activ- about volcanoes and volcano hazards ity but are signs of a still functioning to public officials, land-use planners, volcano. Recent earthquake swarms emergency response organizations, shook Mount Rainier in 2002, 2004, Federal Aviation Administration, 2007, and 2009, for example. National Weather Service, Federal Emergency Management Agency (FEMA), and other federal agencies, the news media, schools, and the general public.

ISSUE UPDATE: JUNE 2010 INTRODUCTION TO VOLCANOES 3

Volcano emergencies are times Who can be affected? of great uncertainty • Severe hazards can affect areas on Restless volcanoes can challenge a volcano’s flanks rapidly. people at risk more than most other natural hazards because they pres- • Communities in valleys that lead ent multiple uncertainties about from a volcano are at risk from when eruptive or other hazardous lahars (volcanic ). People activity will begin, what its charac- at risk must know how to reach ter and magnitude will be, how long high ground off the floor it will last, and who will be affected. so that they can escape before the Unlike and earthquakes, vol- ’s arrival. canic eruptions are seldom singular • Downwind, fall can events; activity is often prolonged be a nuisance or significant threat, over a period of weeks to years. depending on how much ash falls. Sometimes, volcanic unrest does not Shelter in place unless also at risk culminate in an eruption. But, even from a lahar. without eruptions, the uncertainty associated with volcanic unrest can Who’s taking action? cause a major psychological and eco- • For your peace of mind, and so nomic impact on the population. that you can be forewarned, scien- tists use ground-based and remote Principal Messages for the Public sensing instruments to track vol- What can happen? canic activity. • With virtual certainty, Cascade • For your safety, public officials volcanoes will erupt again, even and scientists assemble and within our lifetimes. practice volcano emergency coor- dination plans. • Volcanoes provide us with warn- ing signs of reawakening days to What you can do: months in advance of an eruption, • People who are knowledgeable and but exact timing and size can only prepared can survive in greater be estimated. safety and comfort and with con- • A common scenario is the erup- fidence during the next volcanic tion of volcanic ash, and later eruption. Your family will count melting snow and ice, which can on you to follow these measures. create lahars (volcanic mudflows). Lahars can surge off a restless or erupting volcano and flow down valleys for tens of miles. ISSUE UPDATE: FEBRUARY 2013 4 MEDIA GUIDEBOOK FOR NATURAL HAZARDS IN WASHINGTON

• Learn—Your family, school and business will have a better oppor- tunity to survive safely or recover quickly if they learn now about the location of volcano hazard zones. • Inquire— Inquiring about current volcano conditions, community evacuation plans, and then obey- ing officials can help your family or business survive with less dis- ruption during an eruption. • Prepare—Preparing your home with extra supplies and an emer- gency communication plan may reduce losses and help your family will recover from future volcanic eruptions.

ISSUE UPDATE: FEBRUARY 2013 VOLCANO WARNING FLOW CHART 1

Volcano Warning Flow Chart HOW THE VOLCANO WARNING SYSTEM WORKS

USGS Cascades Volcano Alert NWS sends Volcano EAS Volcano Level Message Message Observatory State EOC and ( WA) Local jurisdictions and land managers and Broadcasters and General distribution to Volcano Aviation public via NOAA Weather Color Code Radio and Internet Message

State EOC sends (via EAS)

Washington DC, EMD / COUNTY VOLCANO WARNING VAAC To: Broadcasters (via EAS) Pre-scripted Message NWS Local jurisdictions FAA Citizens (via NOAA Weather Radio) AHAB Sirens (Pierce County activates for Mount Rainier)

State EOC sends (via EAS) Pre-scripted Message COUNTY EVACUATION This message sent by State EOC at request of County To: Broadcasters via EAS Local jurisdictions Citizens (via NOAA Weather Radio) AHAB Sirens (Pierce County activates for Mount Rainier)

USGS US Geological Survey Washington State EOC: State Emergency Operation Center Military NWS: National Weather Service Department AHAB: All Hazards Alert Broadcast Emergency EAS: Emergency Alert System Management VAAC: Volcano Ash Advisory Center Division FAA: Federal Aviation Administration

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ISSUE UPDATE: JUNE 2010 VOLCANO EXPERT CONTACTS 1

Volcano Expert Contacts

US Geological Survey-Cascades Volcano Observatory 1300 SE Cardinal Court Vancouver, WA 98683 Tel: 360-993-8973 Fax: 360-993-8980 E-mail: [email protected] Website: http://vulcan.wr.usgs.gov/

Pacific Northwest Seismic Network (PNSN) Lab University of Washington Dept. of and Space Sciences Box 351310 , WA 98195-1310 Tel: 206-543-7010 Fax: 206-685-5788 E-mail: [email protected] Website: http://www.pnsn.org/

Washington Emergency Management Division Washington Military Department Emergency Management Division Building 20, MS TA-20 Camp Murray, WA 98430-5112 Tel: 1-800-688-8955 Main Tel: 1-800-562-6108, or 253-512-7000 Website: http://www.emd.wa.gov/

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ISSUE UPDATE: JUNE 2010 VOLCANOE ALERT NOTIFICATION SYSTEM 1

Volcano Alert Notification System

The USGS and its partners keep watch ground and aviation differ substan- over volcanoes within the United tially. In these cases, the Volcano Alert States (U.S.). The USGS is by law Level and Aviation Color Code will mandated to issue notifications re- move independently. garding volcanic activity. In 2006, the USGS adopted a standardized volcano For example, an eruption of a alert-notification system to describe flow that threatens a community but the status of all volcanoes within the produces no signifi­cant ash might U.S. and its territories. The USGS vol- warrant a Volcano Alert Level of cano alert-notification system consists Warning but an Aviation Color Code of two distinct types: of Orange. On the other hand, an l VOLCANO ALERT LEVEL eruption that produces a huge cloud describes the current behavior of volcanic ash that does not drift of a volcano and potential for over inhabited areas might warrant a hazardous impacts to people on Volcano Alert Level of Watch and an the ground. This 4-tiered system Aviation Color Code of Red. uses the terms Normal, Advisory, Watch, and Warning (from back- ground to highest threat). l AVIATION COLOR CODE pro- vides ash-plume information for air traffic control, aircraft, and air- lines. This 4-tiered system uses the terms Green, Yellow, Orange, and Red (from background to highest threat). USGS communications during un- rest and erup­tions include both the Volcano Alert Level and the Aviation Color Code. During unrest (either es- calating or de-escalating) and during most eruptions, the alert-level term and code color will change together (for example, Normal and Green; Advisory and Yellow; Watch and Orange; Warning and Red). However during some volcanic eruptions, the potential impacts to people on the

ISSUE UPDATE: JUNE 2010 2 MEDIA GUIDEBOOK FOR NATURAL HAZARDS IN WASHINGTON

Volcano Alert Levels

These levels are intended to inform people on the ground and are issued in con- junction with the Aviation Color Code.

Volcano Alert Levels Used by USGS Volcano Alert Levels are intended to inform people on the ground about a volcano’s status and are issued in conjunction with the Aviation Color Code. Notifications are is- sued for both increasing and decreasing volcanic activity and are accompanied by text with details (as known) about the of the unrest or eruption and about potential or current hazards and likely outcomes.

Term Description

Normal Volcano is in typical background, noneruptive state Or, after a change from a higher level, Volcanic activity has ceased and volcano has returned to noneruptive background state.

Advisory Volcano is exhibiting signs of elevated unrest above known background level Or, after a change from a higher level, Volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.

Watch Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, Or Eruption is underway but poses limited hazards.

Warning Hazardous eruption is imminent, underway, or suspected.

ISSUE UPDATE: JUNE 2010 ALERT SYSTEMS 1

Know the alert level terms used by USGS volcano observatories Normal The typical background state of a volcano when not erupting. It includes periods of increased steaming, seismic events, defor­mation, thermal anomalies, or detectable levels of volcanic degassing, as long as that activ- ity is within the background range seen during its monitoring history or at similar types of volca­noes. It is not an “alert” level per se, inasmuch as no concern of potentially hazardous activity is implied. In some cases, unrest that is ini­tially seen as “anomalous,” such as increased steaming or elevated seismic activity may after some time become considered normal background activity.

Advisory Declared when one or more volcano monitoring parameters are outside the background range of activity. Progression towards an eruption is by no means certain, but the volcano is closely watched to see how unrest develops. After being downgraded from a higher level, Advisory means that volcanic unrest has decreased significantly but that the level of unrest has not yet reached background.

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ISSUE UPDATE: JUNE 2010 ALERT SYSTEMS 1

Know the alert level terms used by USGS volcano observatories

Watch Declared for two different situations: (1) heightened or escalating unrest indi- cating a higher potential that an eruption is likely but still not certain or (2) an eruption that poses only limited hazard to people on the ground. In situation 2, it is implied that erupting volca­noes are inherently unstable and that condi­ tions could change quickly. After downgrading from Warning to Watch, this level indicates that the potential for renewal of hazardous eruptive activity is high (situation 1) or that the volcano has settled into an eruptive style that poses only limited hazards (situation 2).

Warning Declared when a highly haz­ardous eruption is underway, suspected, or believed to be imminent. Such events include large explosive eruptions that could destroy nearby communities and cause volcanic ash to fall on others downwind, eruptions of lava that are flowing towards nearby homes, and eruptions that could spawn powerful volcanic mudflows (lahars) that might inundate down-stream communities. During an eruption, information accom- panying the alert levels and frequent updates will indicate in as much detail as possible the time of onset, intensity, ash-plume height, and types of hazard- ous phenomena. When an eruption ends or settles into milder, less hazardous activity the level is downgraded.

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ISSUE UPDATE: JUNE 2010 AVIATION COLOR CODE 1

Aviation Color Code

The Aviation Color Code is in accordance with recommended International Civil Aviation Organization procedures. The color code places special em- phasis on volcanic ash in the , because ash can cause jet engines to fail in flight. Also, wind can carry ash clouds thousands of miles, creating a hazard to jet aircraft far distant from the erupting volcano­ .

Aviation Color Code Used by USGS Volcano Observatories Color codes, which are in accordance with recommended International Civil Aviation Organization (ICAO) procedures, are intended to inform the aviation sector about a volcano’s status and are issued in conjunction with an Alert Level. Notifications are issued for both increasing and decreasing volcanic activity and are accompanied by text with details (as known) about the nature of the unrest or eruption, especially in regard to ask-plume information and likely outcomes.

Color Description

Green Volcano is in typical background, noneruptive state Or, after a change from a higher level, Volcanic activity has ceased and volcano has returned to noneruptive background state. Yellow Volcano is exhibiting signs of elevated unrest above known background level Or, after a change from a high level, Volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase. Orange Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, Or Eruption is underway with no or minor volcanic-ash emissions (ash-plume height specified, if possible) Red Eruption is imminent with significant emission of volcanic ash into the atmosphere likely, Or Eruption is underway or suspected with significant emission of volcanic ash into the atmosphere (ash-plume height specified, if possible).

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Know the terms for the Aviation Color Code used by USGS volcano observatories

Aviation Color Code definitions are similar­ to those for Volcano Alert Levels and, like them, are based on a volcano’s activity:

GREEN—Applies to the typical background state of a volcano when not erupting. At volcanoes­ that appear quiet but are not monitored with ground-based instru- ments, the absence of unrest cannot be confirmed; consequently, Green is not assigned to such volcanoes. It is not an “alert” level per se, inasmuch as no concern of potentially hazardous activity is implied.

YELLOW—Declared when one or more monitoring parameters at a volcano are outside the background range of activity. Progression towards an eruption is by no means certain, but the volcano is closely watched to see how unrest develops. After being downgraded from a higher level, Yellow means that volcanic unrest has de- creased significantly but that the level of unrest has not yet reached background.

ORANGE—Used for two different situations: (1) heightened or escalating unrest indicating a higher potential that an eruption is likely but still not certain (the timeframe to eruption­ or cessation of unrest is variable) or (2) an eruption that poses only a minor hazard to aviation because of limited amounts of ash in the atmosphere or low ash-plume heights. After downgrading from Red to Orange, this level signifies that the potential renewal of hazardous eruptive activity is high (situation 1) or that the volcano has settled into an eruptive style that poses only limited hazards (situation 2).

RED—Declared when an is underway, suspected, or imminent that is releasing or likely to release a significant amount of ash into the atmosphere. During such events, accompanying information will indicate in as much detail as possible the time of onset, intensity, and ash-plume height. There will be frequent updates with detailed accompanying text to report on the progression­ of the erup- tion. When the eruption ends, or settles into milder activity with no or minor ash emissions, the level will be downgraded.

ISSUE UPDATE: JUNE 2010 AVIATION COLOR CODE 3

Sample Volcanic Activity Notice (VAN) for change from Normal/Green to Advisory/Yellow

CVO/USGS Volcanic Activity Notice

Volcano: Rainier (CAV W #1201-03-)

Current Volcano Alert Level: ADVISORY Previous Volcano Alert Level: NORMAL

Current Aviation Color Code: YELLOW Previous Aviation Color Code: GREEN

Issued: Thursday, November XX, 2009, XX:XX A.M. PDT (200911XX/XXXXZ) Source: Cascades Volcano Observatory Notice Number: 2009/Cx Location: N 46 deg 21 min W 121 deg 45 min Elevation: 14410 ft (4393 m) Area: ; West- State

Volcanic Activity Summary: The swarm of small earthquakes that began three days ago has persisted and intensified to a level not observed during the past several decades of instrumental monitoring of Mount Rainier. It is uncer- tain whether or not this unrest will culminate in an eruption, but scientists at the USGS and the Pacific Northwest Seismic Network at the University of Washington are beginning continuous, 24-hour surveillance of monitoring data and are planning to install additional instruments on the volcano. Prehistoric eruptions of Mount Rainier have produced modest (less than one-half inch) ashfall in now populated areas of east-central Washington State and the south- ern region, as well as potentially destructive lahars (or volcanic mudflows) in the valleys that head on the volcano. Additional information will be released as warranted.

Recent Observations: [Volcanic cloud height] Nil [Other volcanic cloud information] Nil [Lahar] Nil [Ash fall] Nil

Contacts: CVO Scientist in Charge and Duty Scientist

Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://vulcan.wr.usgs.gov

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Sample Volcanic Activity Notice (VAN) for change from Advisory/Yellow to Watch/Orange

CVO/USGS Volcanic Activity Notice

Volcano: Rainier (CAV W #1201-03-)

Current Volcano Alert Level: WATCH Previous Volcano Alert Level: ADVISORY

Current Aviation Color Code: ORANGE Previous Aviation Color Code: YELLOW

Issued: Thursday, December XX, 2009, XX:XX A.M. PDT (200912XX/XXXXZ) Source: Cascades Volcano Observatory Notice Number: 2009/Cx Location: N 46 deg 21 min W 121 deg 45 min Elevation: 14410 ft (4393 m) Area: Cascade Range; West-Central Washington State

Volcanic Activity Summary: The ongoing unrest at Mount Rainier has evolved significantly during the past 12 hours prompting a rise in the alert level. Swarms of shallow (less than 2 miles below the summit) earthquakes have intensified in duration and in number of events per hour. Continuous GPS instruments on the volcano’s flanks are now clearly recording a slow inflation. Both of these observations suggest that has risen into the volcano and that the probability of this unrest culminating in eruption has increased. Such eruptions will produce ash clouds and will also likely produce lahars in some or all valleys draining the volcano. Scientists at USGS and the Pacific Northwest Seismic Network at University of Washington continue to monitor the volcano 24 hours a day and will issue additional information as warranted.

Recent Observations: [Volcanic cloud height] Nil [Other volcanic cloud information] Nil [Lahar] Nil [Ash fall] Nil

Contacts: CVO Scientist in Charge and Duty Scientist

Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://vulcan.wr.usgs.gov

ISSUE UPDATE: JUNE 2010 AVIATION COLOR CODE 5

Sample Volcanic Activity Notice (VAN) for change from Watch/Orange to Warning/Red

CVO/USGS Volcanic Activity Notice

Volcano: Rainier (CAV W #1201-03-)

Current Volcano Alert Level: WARNING Previous Volcano Alert Level: WATCH

Current Aviation Color Code: RED Previous Aviation Color Code: ORANGE

Issued: Thursday, December XX, 2009, XX:XX A.M. PDT (200912XX/XXXXZ) Source: Cascades Volcano Observatory Notice Number: 2009/Cx Location: N 46 deg 21 min W 121 deg 45 min Elevation: 14410 ft (4393 m) Area: Cascade Range; West-Central Washington State

Volcanic Activity Summary: An explosive eruption of Mount Rainier began at approximately XX:XX PST, December XX, 2009 (XXXX UTC). CVO is raising the aviation color code to Red and the alert level to Warning. Initial height of the eruption cloud is estimated at about 30,000 feet above sea level. The erup- tion cloud will carry ash northeastward. There is a high probability that lahars have been produced in some valleys that head on the volcano. Further reports will be issued as more information becomes available.

Recent Observations: [Volcanic cloud height] Initial height of the eruption cloud is estimated at about 30,000 ft above sea level. [Other volcanic cloud information] Nil [Lahar] Lahars are possible on Puyallup, , White, Cowlitz, and Nisqually . [Ash fall] Ashfall is likely in the vicinity of and downwind (northeast) from the volcano.

Contacts: CVO Scientist in Charge and Duty Scientist

Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://vulcan.wr.usgs.gov

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ISSUE UPDATE: JUNE 2010 VOLCANO HAZARD MAPS 1

Volcano Hazard Maps

Volcano hazard maps appear on the following pages for each of the five prin- cipal volcanoes in Washington as well as Mount Hood, Oregon, which also poses a threat to Washington. They have been simplified from more detailed maps in hazard assessments that are posted on the USGS-CVO web site http://vulcan.wr.usgs.gov. Hazard zones are based upon the extent of previous vol- canic activity at each volcano and on the types and sizes of eruptions expected in the future.

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Hazard Notes These hazard maps show areas that could be affected by lahars, lava flows, and pyroclastic flows from the volcanoes if events similar in size to past events were to occur. Because small lahars are more common than large ones, most lahars would be less extensive than the hazard zones shown on the maps, but a few could be more extensive. Lahar hazard is not equal in all valleys. Hazard zone boundaries are approximate. Scientists continue to reevaluate the hazard zones as they learn more about these volcanoes. Areas at risk from volcanic ash fall are not shown on the maps because the threat depends upon the size and type of the eruption and the speed and direction of winds. Winds blow towards the east much of the time, and thus, ash is more likely to be blown across the Cascade Range to and beyond, but ashfall can affect the more densely populated areas west of the Cascades. In addition, under certain wind conditions, ashfall from out-of-state volcanoes can affect Washington.

ISSUE UPDATE: JUNE 2010 VOLCANO HAZARD MAPS 3

Whatcom / Skagit Counties, WA

Mount Baker

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Skagit / Snohomish Counties, WA

Glacier Peak

ISSUE UPDATE: FEBRUARY 2013 VOLCANO HAZARD MAPS 5

Pierce / King / Thurston / Lewis Counties, WA Mount Rainier

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Pierce / King / Thurston / Lewis Counties, WA Mount Rainier (insert maps)

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Cowlitz / Lewis / Skamania Counties, WA Mount St. Helens

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Klickitat / Yakima / Skamania Counties, WA Mount Adams

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Hood / Clackamas / Wasco / Multnomah Counties, OR Mount Hood

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ISSUE UPDATE: JUNE 2010 VOLCANIC HAZARDS 1

Volcanic Hazards

ISSUE UPDATE: JUNE 2010 2 MEDIA GUIDEBOOK FOR NATURAL HAZARDS IN WASHINGTON

Tephra (includes in thickness and becomes wet. Ash volcanic ash) from an erupting volcano can tem- porarily disrupt transportation and A note about terminology: Scientists communication routes distant from commonly use the term to the . When wet, it can refer to fragments of volcanic cause short circuits in power trans- and lava (regardless of size) that are mission lines. blasted into the air by or carried upward by hot gases in erup- On the morning of May 18, 1980, tion columns or lava fountains and Mount St. Helens blasted an enor- fall back to Earth’s surface. Tephra mous column of volcanic ash and gas includes large blocks and bombs more than 80,000 feet into the air. (boulder size) to fine ash (dust size). By the end of the day, more than 500 Grains that are size or smaller million tons of ash had fallen onto are called ash. parts of Washington, Idaho, and Montana. The ash disrupted travel What is volcanic ash? because of poor visibility, slippery Is it hazardous? roads, and ash-damaged vehicles. At The largest rock fragments expelled least 10,000 people became stranded, by eruptions usually fall back to the and many small communities became ground within two miles of the vent, isolated because of this impact on but small fragments of volcanic ash transportation. rise high into the air and fall out far downwind. When ash falls in these Volcanic ash — downwind areas it has cooled to sur- A hazard to aviation rounding air temperature. Volcanic Volcanic ash poses a significant haz- ash is normally not poisonous to ard to aircraft as far as thousands people or pets, but fluorine-rich or of miles from an erupting volcano. very thick ash can be a hazard to When ash particles encounter air- grazing animals. craft traveling at speeds of several hundred knots, they cause abra- Volcanic ash can be a nuisance or a sion to the windshield and other hazard, depending on the amount parts of the aircraft. The overall that falls and its grain size. Even a result of an aircraft’s flying into an fraction of an inch can disrupt life ash cloud can be degraded engine for people many miles from the vol- performance (including flame cano for long periods of time and can out), loss of visibility, and failure make breathing difficult and irritate of critical navigational and oper- the eyes. It can reduce visibility and ational instruments. There are no make driving difficult. Volcanic ash remote volcanoes when it comes to can damage machinery. Ash clogs volcanic ash. filters, drains, and sewer systems. It can collapse roofs of some buildings One of the first potentially life- when it exceeds about four inches threatening ash/aviation incidents

ISSUE UPDATE: JUNE 2010 VOLCANIC HAZARDS 3 recognized occurred during the erup- The VAACs are tasked with the detec- tion of Mount St. Helens in May 1980. tion, tracking, and forecasting of the On May 18, 1980, a McDonnell– movement of eruption clouds within Douglas DC-9-30 flying through their respective areas of responsi- the ash cloud suffered damage to bility. Ash clouds in Washington engine parts, surface abrasion to the and Oregon are the responsibility of windshield, and a clogged hydraulic the VAAC in Washington, D.C. The system; and a Boeing 747 sustained USGS and its partners work continu- damage from ash while parked on ously with the VAACs, FAA, and US the ground. A week later on May 25, military and commercial airlines to 1980, a C-130 Hercules flew through advise them about volcanic events the cloud of a smaller eruption while and to aid pilot training concerning en route from Tacoma, Washington, volcanic hazards. to Portland, Oregon. The plane suf- Although recent eruptions of Mount fered temporary engine failure, St. Helens did not damage many air- permanent engine damage, and con- craft, along North Pacific air routes, tamination to air handling systems, some of the busiest in the world, at hydraulic lines, and pitot tubes. A least 15 aircraft have been damaged day later, two Boeing 727 transport since 1980 by flying through volca- jets also encountered the ash cloud nic ash clouds. The 2010 eruption of and suffered engine damage. ash from Eyjafjallajokull volcano in The May 25 incident was the first doc- and its disruption to travel umented encounter resulting in jet and business caused damages in the power loss. The May 18 DC-9 incident billions of dollars. was the first known to involve engine damage. These incidents and the sig- Volcanic gases nificant failures of aircraft engines More than ninety percent of gas in (1982) and emitted by volcanoes is (1989) prompted interagency coop- (). Other common volcanic eration between the USGS, National gases are and Oceanographic and Atmospheric dioxide. Administration (NOAA), the Federal Aviation Administration (FAA), Volcanic gases floating freely in the the International Civil Aviation atmosphere are not a hazard to peo- Organization (ICAO) and represen- ple and animals unless they are in tatives of the airline industry. high concentrations, which typically is not an issue away from vents. In 1995 nine regional Volcanic Ash Advisory Centers (VAACs) were But odorless carbon dioxide is heavier established around the world under than air and can become trapped in the auspices of the International ice and topographic depres- Civil Aviation Organization to issue sions on volcanoes where it displaces volcanic ash warnings to aircraft. the air and can be deadly.

ISSUE UPDATE: JUNE 2010 4 MEDIA GUIDEBOOK FOR NATURAL HAZARDS IN WASHINGTON

Since the 1980s, carbon dioxide collapse on the steep-sided slopes of release has been unusually high at a volcano can cause of hot volcano in east- rock and gas (pyroclastic flows) that central California. In 2006, three can incinerate whatever lies in their members of the ski patrol there died path. On snow-covered volcanoes, and their four would-be rescuers pyroclastic flows melt snow and ice were hospitalized after a thin snow and produce lahars. These lahars can bridge collapsed and plunged them have disastrous effects tens of miles into a carbon-dioxide-filled hole. down valley from the volcano. The collapse of lava flows and domes are gas can react with one of the greatest volcano threats water in the atmosphere to create worldwide. , which can cause corrosion and harm vegetation downwind. Pyroclastic flows Lava flows and Pyroclastic flows are high-speed ava- lanches of hot ash, rock fragments, lava domes and gas that can move down the Molten rock that erupts onto the sides of a volcano during explosive Earth’s surface is called lava. The eruptions or when a growing lava hottest, most fluid lava flows at dome or flow collapses and breaks Washington’s volcanoes tend to apart. Pyroclastic flows can be as hot travel only short distances from a as 1,500°F and move at speeds of 40 vent, rarely moving beyond the base to 80 miles per hour. Such flows tend of a volcano. Once solidified, they to follow valleys and are capable of typically form much of a volcano’s knocking down and burning every- cone. For example, most Cascade thing in their paths. volcanoes consist of hundreds of overlapping layers of lava flows and In the recent geologic past, Glacier rock rubble. Peak and Mount Hood have gener- ated hundreds of pyroclastic flows Slightly cooler or crystal-rich lava that have swept down the slopes of oozes to the surface in a semi-solid the volcano. Some resulted from large form and piles high in mounds called explosive eruptions that produced lava domes. During eruptions in voluminous flows of and 1980-86 and 2004-2008 at Mount St. ash near the volcano and substan- Helens, lava extruded onto the crater tial ashfall in eastern Washington floor to form lava domes. Substantial and beyond. Other pyroclastic flows portions of , Mount St. resulted from frequent collapses of Helens, and Mount Hood are con- growing lava domes. The flows buried structed of lava domes. valley floors tens to hundreds of feet Lava flows and lava domes in them- deep and perhaps started forest fires. selves seldom are a direct hazard A modern example is the 1991-1995 beyond the base of a volcano, but their eruption of volcano in . Portions of that col- ISSUE UPDATE: JUNE 2010 VOLCANIC HAZARDS 5 lapsed and formed pyroclastic flows Avalanches that traveled almost three miles Debris avalanches are rapidly mov- from the crater where they destroyed ing that can range in size about 2,000 houses and claimed the from small events affecting only a lives of 43 people. limited area to catastrophic move- Lava domes that grew in the crater ments, such as massive collapses of of Mount St. Helens from 1980-86 the entire summit or sides of a vol- and 2004-08 were nestled within cano. Some Cascade volcanoes are the walls of the crater on a relatively susceptible to debris avalanches floor and did not produce many because portions of them are built of collapses or pyroclastic flows. If lava weak materials or have been weak- eventually fills the crater, pyroclastic ened by attack from acidic volcanic flows could sweep all the volcano’s fluids, a process called hydrother- flanks. mal alteration. Eruptions, intense rainfall, or large local earthquakes At most Cascade volcanoes, pyro- can trigger debris avalanches on vol- clastic flows seldom travel more than canoes. Most large prehistoric debris a few miles beyond the base of the avalanches from Cascade volcanoes volcano, but their potential to swiftly happened during volcanic eruptions, melt snow and ice and generate far- but some debris avalanches occurred traveling volcanic mudflows, called when a volcano was quiet. lahars, makes them an even more hazardous process. Lahars Lahars are flows of , rock, and Debris avalanches, lahars water that can rush down valleys and (volcanic mudflows), and stream channels at speeds of 20 to 40 debris flows miles per hour and can travel more A note about terminology: The terms than 50 miles. Some lahars resemble debris flows, mudflows, and lahars fast-moving rivers of wet concrete. are sometimes used interchange- Close to their source, these flows ably. prefer to use are powerful enough to rip up and the term lahar for flows of water, carry trees, houses, and huge boul- rock, mud, and other debris that ders for miles. Farther downstream originate on a volcano. However, at they entomb everything in their path Mount Rainier, where small such in mud. Lahars differ from floods in flows occur frequently, we use the that they contain higher concentra- term to distinguish them tions of mud and rocks. from large lahars, which can affect Historically, lahars have been one people catastrophically tens of miles of the deadliest volcano hazards from the mountain. The term debris because they can reach lowland describes a type of rapidly areas quickly and bury them in mud moving that is common on and rock debris. Most lahars from some volcanoes. 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Cascade volcanoes originate by the mile of the north flank and summit of rapid melting of snow and ice during the volcano, traveled 14 miles down eruptions. Other lahars are generated valley in 10 minutes, and buried the by debris avalanches that contain valley to an average depth of 150 feet. sufficient water to transform all or Fortunately for downstream commu- part of the avalanche into a lahar. nities, the avalanche did not contain Large lahars are a potential hazard enough water to mobilize entirely to many communities downstream into a lahar as did the Osceola. The from glacier-clad volcanoes. During Mount St. Helens event ranks as one volcanic unrest or eruption, people of the largest terrestrial landslides in in potentially hazardous areas should historical time. be prepared to move rapidly to high ground out of lahar hazard zones. Lahars and Debris flows Lahars choke river channels and at Mount Rainier cover valley floors with large At Mount Rainier, lahar hazards are amounts of sediment. Such dis- evaluated at two different scales: ruption of watersheds can initiate small flows that occur almost annu- years or decades of high sediment ally and threaten campgrounds, production, shifting stream chan- hiking trails, and roads within the nels, increased flooding, and burial National Park (referred to as debris of downstream areas by sediment. flows in emergency management Unlike areas affected by other natu- plans), and much more infrequent ral hazards such as earthquakes or large flows that threaten river valleys floods, the lingering consequences all the way to Puget Sound (referred of a volcanic eruption can make to as lahars in emergency manage- areas unavailable for redevelopment ment plans). The small (but still long after an eruption ends. dangerous) debris flows are triggered primarily in summer and autumn, A prehistoric debris avalanche at when are producing and Mount Rainier and one in 1980 at storing large volumes of meltwater Mount St. Helens are the best known and when intense rainfall can erode examples in Washington. A debris sparsely vegetated ice-free areas of avalanche 5,600 years ago (com- steep ground. Since 1992 dozens of monly called the Osceola ) debris flows at Mount Rainier have removed almost one cubic mile of destroyed roads and buried trails the northeast flank and summit of and picnic areas, while similar flows Mount Rainier before transforming at Mount Hood have caused millions into a lahar that swept more than of dollars of damage to roads and 70 miles downstream through areas bridges. now densely populated and into Puget Sound. On May 18, 1980, a debris avalanche on Mount St. Helens removed about two-thirds of a cubic

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Lahar detection system River at Mount St. Helens. The tele- and evacuation signage metered data go to the USGS-CVO, the National Weather Service Office near Mount Rainier in Portland, which will broadcast warnings.

The risk from lahars is greater on the west slope of Mount Rainier than at other locations in the Cascades because of the existence of large amounts of weakened rock on the volcano’s west side that is subject to landsliding, coupled with dense resi- dential and commercial development in the valley below. As a result, Pierce County Department of Emergency Management, in collaboration with the USGS and Washington State Emergency Management Division, maintains a lahar warning system in the Puyallup and Carbon River valleys. In the event of a lahar, automated signals will be sent to the Pierce County Law Enforcement Support Agency (LESA) and Washington State Emergency Operations Center at Camp Murray. The public will be notified through multiple chan- nels including sirens, the emergency alert system, broadcasts on NOAA weather radios, and other forms of mass communication. The USGS also operates a lahar detection system on the Toutle ISSUE UPDATE: JUNE 2010 8 MEDIA GUIDEBOOK FOR NATURAL HAZARDS IN WASHINGTON

Safety Precautions

Preparing for gency housing, what emergency volcanic activity supplies to keep on hand, and how to be self sufficient for several days, Society cannot always abandon or as recommended by local emergency prevent settlement of areas where management agencies. volcanic hazards exist; what is important is to learn to live with them as safely as possible. General safety principles Hazards on volcanoes—Lava Learn flows, pyroclastic flows, and Determine whether you live, work, volcanic gases or go to school in a volcano haz- l Obey closures. Listen to advice ard zone. Learn about all volcanic from public safety agencies and processes that could affect your com- land managers regarding access munity. Residents can obtain copies restrictions and safety recom- of USGS volcano-hazard reports to mendations before and during a determine whether they live or work volcano crisis. in areas at risk from volcanic activity. Everyone should plan how they and Hazards on valley floors— their families will respond to any Lahars and debris flows natural , including unrest or l If you are on the floor of a valley eruptive activity at nearby volcanoes. that originates on a Cascade vol- cano, and you receive a warning Inquire that a lahar is in progress, follow Ask local emergency management the instructions of officials. You offices to advise you about how to will probably be instructed to respond during any emergency. move to high ground 50 to 100 feet Residents who live near a volcano off the valley floor. should also find out what their local officials are doing to prepare their l When hiking in valleys on the community for the possibility of slopes of Cascade volcanoes dur- renewed volcanic activity. ing late summer or during intense rainfall, be alert for the signs of an Plan approaching debris flow—ground shaking and low roaring sound— Develop an emergency plan with and move quickly up the valley your family so that you are prepared wall to higher ground. When you for natural hazards and emergencies. hear it, you may have only minutes Preparation might include knowing to escape. where to go when family members are separated, where to go for emer-

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What to do during l Wind and activity can an ash fall resuspend volcanic ash long after an eruption. l Know in advance what to expect and how to deal with volcanic l Be alert for signs of structural ash. weakening of buildings when accumulations of wet ash exceed a l Prepare to shelter in place with thickness of about 4 inches. emergency supplies on hand, rather than evacuating from ash- How do I clean up? affected areas. l Minimize activities that resuspend l Keep ash out of buildings, ash by removing as much ash as machinery, air and water sup- possible from frequently used plies, downspouts, storm drains, areas. etc., as much as possible to reduce l Clean from the top down and wear problems. a dust mask. Dampening the ash l Wet ash can cause electrical shorts may ease removal, but be careful and disruption of power systems not to wash ash into drainpipes, and require the use of backup sewers, storm drains, etc. power sources. l Use water sparingly because wide- l Stay indoors to reduce exposure— spread use of water for clean-up especially if you have respiratory may deplete public water supplies ailments. and clog drainage systems. l Minimize travel—driving in ash is l Caution: Fine ash is slippery when hazardous to you and your car. wet. l In ash-filled air, use dust masks and eye protection to reduce irrita- tion. If you don’t have a dust mask, use a wet handkerchief. l Don’t tie up phone lines with non- emergency calls. l Use your radio to receive informa- tion about ash fall.

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Volcano Histories

Histories of Washington 1986 and 2004 to 2008) to explosive volcanoes and Mount eruptions much larger than that of May 18, 1980. Mount St. Helens has Hood, Oregon produced large plumes of volcanic ash MOUNT BAKER erupted in the mid- throughout its recent history—more 1800s for the first time in several than any other Cascade volcano. thousand years. Activity at steam MOUNT ADAMS has produced few vents () in , eruptions during the past several near the volcano’s summit, increased thousand years. This volcano’s most in 1975 and is still vigorous, but recent activity was a series of small there is no evidence that an eruption eruptions about 1,000 years ago. The is imminent. upper slopes of Mount Adams have GLACIER PEAK has erupted at least been weakened by long-term expo- six times in the past 4,000 years. sure to hot, acidic volcanic fluids, About 13,000 years ago, an espe- and this has made some areas espe- cially powerful series of eruptions cially prone to debris avalanches. deposited volcanic ash at least as far MOUNT HOOD has erupted several away as . times during the past 2,000 years, MOUNT RAINIER has produced most recently during the late 18th more than a dozen eruptions and and the mid-19th centuries. Although numerous lahars in the past 4,000 not an explosive volcano, Mount years. The most recent lava flow hap- Hood has generated large lahars from pened about 1,000 years ago, though collapsed lava domes and pyroclastic pioneers in 1894-95 watched steam flows. In 1805 explorers Lewis and explosions at the volcano’s summit. Clark named the river now known It is capped by as much glacier ice as the Sandy River, the Quicksand as the rest of the Cascade volcanoes because of the large amount of sand combined, and parts of Rainier’s steep at its mouth. Today we recognize that slopes have been weakened by hot, multiple lahars from Mount Hood acidic volcanic fluids. These factors deposited the sand, the most recent make this volcano especially prone in 1791. to debris avalanches and lahars. MOUNT ST. HELENS has been the most frequently active volcano in the Cascades during the past 4,000 years. It has produced many lahars and a wide variety of eruptive activ- ity, from relatively quiet eruptions of lava (most recently in late 1980 to ISSUE UPDATE: JUNE 2010 VOLCANO HISTORIES 11

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Frequently Asked Questions

What are the hazards from of volcanic unrest partly by monitor- Washington’s Cascade volcanoes? ing the pace and intensity of such Lahars are the principal hazards to life activity. and property at Washington State’s How many volcanoes exist in the volcanoes; volcanic ash can be a wide- and its territories? spread nuisance or threat, depending The United States and its territories upon the amount of ash produced have about 170 volcanoes that have in the eruption and where and how been active during the past 10,000 thickly it falls. years, and most could erupt again in Which Cascade volcano the future. In the past 500 years, 80 will erupt next? U.S. volcanoes have erupted one or No one knows for sure, but seven of more times. them have erupted in just the past How many potentially active 300 years: Mount St. Helens (1800- volcanoes are there on Earth? 1857, 1980-1986, and 2004-2008), There are about 1500 potentially ac- (1914-1917), Mount tive volcanoes worldwide, aside from Baker (1843), Glacier Peak (1700s), the continuous belt of volcanoes on Mount Rainier (1894-95), Mount the ocean floor. About 500 of these Hood (1780-1793), and have erupted in historical time. (1786). Any of these could be the next to erupt, though the odds are highest at Mount St. Helens. What kinds of unusual activity might be noticed before an eruption? Common symptoms of volcanic unrest include an increase in the fre- quency or intensity of earthquakes beneath a volcano; the occurrence of volcanic tremor; swelling, subsidence, or cracking of the ground; increased steam emission or small steam explo- sions; melting snow or ice; changes in existing fumaroles or hot springs, or the appearance of new ones; and in- creased discharge of magmatic gases. Volcanologists assess the significance

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Resources

USGS Volcano Hazards Program ...... http://volcanoes.usgs.gov General information about volcanic processes (including extensive information about the effects of volcanic ash and recommendations for cleanup), alert system, hazard assessments, fact sheets, educational materials

USGS Cascades Volcano Observatory . . . . . http://vulcan.wr.usgs.gov General information about Cascade volcanoes

Pacific Northwest Seismic Network http://www.pnsn.org Current and past earthquake data and maps

Washington Emergency Management Division . http://www.emd.wa.gov Inter-agency volcanic eruption response plans, preparedness recommendations

International Volcanic Health Hazard Network (IVHHN) ...... www.ivhhn.org Pamphlets: Health hazards of volcanic ash—a guide for the public, and Guidelines on preparedness before, during and after an ashfall

International Association for and Chemistry of Earth’s Interior (IAVCEI) DVD . . http://www.iavcei.org Understanding Volcanic Hazards; Reducing Volcanic Risk (both sections available in English and Spanish)

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ISSUE UPDATE: JUNE 2010