Original broadcast: March 30, 2004 Hunt for the Supertwister Before Watching 1 Ask students how tornadoes, hurricanes, and high winds differ. What kind of severe weather have students experienced? What actions Program Overview do individuals take in preparing NOVA profiles the deadliest of tornadoes— for these events? What actions do governments take? Why is it supertwisters—and investigates prediction methods. important to understand how The program: severe weather happens? • recounts the May 3, 2003, supertwister that decimated Bridge Creek 2 Review with students the Fujita and Moore, Oklahoma, destroying 8,000 homes, killing 40 people, and wind damage scale, known as the causing $1 billion of damage. F-scale. Developed by meteorologist T. Theodore Fujita in 1971, the • relates some of the factors believed necessary for a tornado to form. F-scale is a widely used tornado • describes one scientist’s proposal to increase the number of Doppler rating method even though it has radars in high-incident tornado regions. never been scientifically tested. • reviews the 1999 Oklahoma City and the 2002 La Plata, Maryland, Emphasize to students that the rating, which is made after the tornado events. tornadic event, is subjective • follows researchers Josh Wurman and Howie Bluestein as they study depending on who is doing the active tornadoes with radar-equipped trucks. rating. Find information about the • accompanies a stormchasing tour company that sights and chases an scale at www.spc.noaa.gov/faq/ F4 supertwister with winds of more than 200 miles per hour. tornado/f-scale.html • looks at computer simulations that help researchers model tornado 3 Organize students into two groups. behavior. As they watch, have one group take • highlights the discovery of a new layer of complexity—the formation notes on the factors involved in the formation of tornadoes and the of mini-tornadoes at ground level—that may be the key to better other group take notes on the tornado prediction. tools and methods used to predict tornadoes.

Taping Rights: Can be used up to one year after the program is taped off the air. AFTER WATCHING

1 Create a list on the blackboard of the factors involved in tornado formation and the tools and methods used to predict them. How do tornadoes form? Why are they so hard to predict?

2 Ask students to think of ways in which humans control their environ- ment (e.g., air conditioning, heat- ing, landscaping, swimming pools). What are some parts of the environ- ment that humans cannot control (e.g., weather, avalanches, earth- quakes, volcanic eruptions)? What are some ways people try to cope with natural disasters?

 NOVA Teacher’s Guide www.pbs.org/nova/tornado CLASSROOM ACTIVITY STANDARDS CONNECTIONs Objective The “Spotting Tornadoes” activity To identify the best time of year and place to position spotters to see aligns with the following National possible tornado outbreaks. Science Education Standards.

Grades 5–8 Materials for each team member Content Standard F: • copy of the “Spotting Tornadoes” student handout Science in Personal and Social • copy of the “Where the Tornadoes Are” student handout Perspectives Natural hazards • access to print and Internet resources • Internal and external processes of the Earth system cause natural Procedure hazards, events that change or destroy human and wildlife 1 Tornadoes can produce winds of more than 300 miles per hour, destroy habitats, damage property, and homes, and kill people. Because tornadoes are extremely difficult to harm and kill humans. predict, the National Weather Service relies on spotters to be its eyes • Natural hazards can present and ears in the field. Tell students that in this activity, they will be personal and societal challenges helping to identify the best time of year and place to position spotters because misidentifying the change to see possible tornado outbreaks. or incorrectly estimating the rate 2 Ask students in what areas of the United States they think tornadoes and scale of change may result in either too little attention and occur most often. Do they think tornadoes are more likely to occur at significant human costs or too certain times of the year? If so, when? Why? Is there anywhere that much cost for unneeded preventive tornadoes cannot form? measures. 3 Organize students into teams and distribute the student handouts. Grades 9–12 Have them follow the instructions on their handouts and encourage Content Standard F: them to present their information using a poster, a mockup of a Science in Personal and Social newspaper, a multimedia presentation, or a play. Perspectives Natural and human-induced 4 To conclude the lesson, discuss what students learned and clear up any hazards remaining questions about tornado occurrence, spotting, and safety. • Natural and human-induced 5 As an extension, have students choose one of the following research hazards present the need for and reporting tasks: humans to assess potential danger a) Draw two illustrations that describe tornado myths. Include why and risk. Many changes in the environment designed by humans the myths are untrue. bring benefits to society, as well as b) Prepare a table describing the Fujita tornado damage scale. cause risks. Students should under- Include examples so that classmates could use the scale to stand the costs and trade-offs of rate a tornado. various hazards—ranging from c) Research and report on where your state ranks in those with minor risk to a few people to major catastrophes with tornado events. Find state rankings at major risk to many people. www.spc.noaa.gov/archive/tornadoes/st-trank.html

Video is not required for this activity.

Classroom Activity Author Developed by WGBH Educational Outreach staff. hunt for the supertwister  NOVA Teacher’s Guide www.pbs.org/nova/tornado ACTIVITY Answer

Tornadoes usually occur during Scientists use technology like recourse is: a thunderstorm, although some Doppler radar to plot thunderstorms • laying down on the lowest floor tornadoes are formed by hurri- that could provide tornadoes and to of the building; canes. Meteorologists look for predict where they are headed. • shielding your head and body atmospheric conditions that will Satellites take pictures of cloud for- areas from debris; provide the four ingredients that mations for study. But volunteer • avoiding windows, doors, and contribute to tornado formation: spotters, who are trained by meteo- outside walls; and moisture, instability, lift, and wind rologists, are the final critical link in • putting as many walls between shear. These conditions can be the information chain. They provide you and the outside as present in giant thunderstorms details about whether tornadoes are possible. called supercells, which are charac- actually being produced and can terized by intense rotation within pinpoint their precise location. The best time and most likely place the storm. Supertwisters are the for a spotter to see a tornado is Some spotters follow tornadoes in most powerful of all tornadoes. between April through June in a vehicle; others observe the torna- central Oklahoma. Spotters are less Tornadoes form when warm, moist do from a fixed location. Safety tips needed in the regions that have a air that is pushed upward by a for mobile spotters include low risk of tornadoes; i.e., west of mass of cold air forms a thunder- • always having a passenger who the Rockies and east of the storm. An updraft within the storm sights the tornado; Appalachian Mountains from cloud can create a mesocyclone, a • being on the lookout for other Virginia northward. large mass of rotating air. When storm spectators; this mass comes in contact with • making sure your vehicle is well The peak season for tornadoes the ground it becomes a tornado. maintained and has a full tank begins in late winter in southern of gas; sections of the United States and Most U.S. tornadoes occur in • staying aware of lightning, shifts northward through mid- Tornado Alley, a relatively flat which all thunderstorms summer. However, tornadoes can Midwestern area that includes produce; occur at any time of the year where Texas, Oklahoma, Kansas, • avoiding the most intense parts conditions are favorable; violent Nebraska, Iowa, Illinois, Indiana, of the storm; tornadoes have even been reported Missouri, Arkansas, and western • being aware of what else is in mountainous regions. While Colorado. Warm, moist air from the going on around you besides tornadoes have been reported in all Gulf of Mexico converges with cold, the storm; and 50 states, weather conditions are dry air from Canada and the Rocky • having an escape route planned not favorable in Alaska and Hawaii Mountains, creating favorable con- at all times. for the type of storms that generate ditions for the type of thunder- tornadoes. According to the storms that might spawn torna- Fixed spotters should also have a National Oceanic and Atmospheric does. In Florida and the Southeast safety plan in place (as should Administration only one tornado region, tornadoes often result from anyone in a fixed location who was reported for Alaska and only 28 hurricanes. encounters a tornado). Everyone in for Hawaii in the years 1950–1996, a high-risk area should know how while Texas reported 5,860 during Major funding for NOVA to find shelter, such as a basement the same period. Based on those is provided by Google or underground safe room, in case numbers, it would not be necessary and BP. Additional funding is provided a tornado approaches unexpected- to locate a spotter in those by the Howard Hughes ly. If no place is available, the best low-incident locations. Medical Institute, the Corporation for Public Broadcasting, and public television viewers.

 NOVA Teacher’s Guide www.pbs.org/nova/tornado links and books ACTIVITY Answer links and books Links Books NOVA Web Site—Hunt for the Tornado Project Online Allaby, Michael. Supertwister www.tornadoproject.com/ Tornadoes. www.pbs.org/nova/tornado/ Provides tornado data along with personal New York: Facts On File, 1997. In this companion Web site to the NOVA experiences, tornado oddities, and tornado Explains the science behind tornadoes and program, discover why tornadoes are more myths. describes the consequences of significant frequent in the United States, read one tornadoes from the past. Tornadoes story about how forecasting has changed, www.noaa.gov/tornadoes.html learn about how building practices affect Bluestein, Howard B. Includes lists of the deadliest outbreaks, sig- tornado safety, and rate tornado damage Tornado Alley: Monster Storms of the nificant tornadoes of the 20th century, and using the Fujita scale. Great Plains. long-term averages by state. New York: Oxford University Press, 1999. May 4, 2003 Severe Weather Outbreak Tornadoes: Nature’s Most Violent Storms Presents a historical account of tornado mcc.sws.uiuc.edu/html/historical/ www.crh.noaa.gov/lmk/tornado/index.html research and an in-depth look at cause may0403svrwx.htm Features information on what tornadoes and effect. Details the tornado outbreak of May 4, are and how they form as well as photos of 2003. tornado damage and tips on staying safe Bradford, Marlene. May 8, 2003 Severe Storms in the during a tornado. Scanning the Skies: A History of Tornado Midlands Forecasting. Weather Watch: Tornadoes www.hprcc.unl.edu/nebraska/may8- Norman, Oklahoma: University of teacher.scholastic.com/activities/wwatch/tor- 2003storm-report.html Oklahoma Press, 2001. nado/index.htm Provides a comprehensive storm report on Outlines the history of today’s tornado Provides background information on the May 8, 2003 tornado event. warning system and explains how tornadoes, hands-on weather activities, technological advancements have May 15, 2003: Record Number of and weather experts’ answers to student greatly reduced tornado fatalities. Tornadoes in the Texas and Oklahoma questions about tornado prediction and Panhandles stormchasing. Grazulis, Thomas P. www.srh.noaa.gov/ama/Research/may_15_ The Tornado: Nature’s Ultimate 2003/030515.html Windstorm. Details the tornado outbreak of May 15, Norman, Oklahoma: University of 2003. Oklahoma Press, 2001. Explains the science behind tornadoes The Online Tornado FAQ and includes personal accounts, photos www.spc.noaa.gov/faq/tornado/ of tornadoes and their aftermath, and Contains a comprehensive guide to tornado information about tornadoes occurring facts including forecasting, climatology, outside the United States. spotting and chasing, and the Fujita tornado intensity scale. Verkaik, Jerrine and Arjen Verkaik. Questions and Answers About Tornadoes Under the Whirlwind: Everything You www.nssl.noaa.gov/edu/tornado Need to Know About Tornadoes but Provides tornado information for kids, Didn’t Know Who to Ask. parents, and teachers, including tips on Elmwood, Ontario: Whirlwind Books, safety and tornado detection. 2001. Explains tornado formation and measure- ments utilizing photos, charts, and diagrams. Specifies tornado safety and preventative building tips, and offers advice on dealing with insurance companies and post-tornado trauma.

hunt for the supertwister  NOVA Teacher’s Guide www.pbs.org/nova/tornado Hunt for the Supertwister Student Handout Spotting Tornadoes

Tornadoes can be violent, destructive, and difficult • How do tornadoes form? to predict, making them one of the most feared • What methods do scientists use to track forms of extreme weather. An official from the tornadoes? National Weather Service needs your help to find • In what areas of the United States do the most likely place that significant (rated F2 or tornadoes occur with the greatest frequency? higher) tornadoes will form this year. Use all the 2 Your safety is the meteorologist’s main concern. resources you have been given and answer the To make sure you will be safe while you are out questions below. chasing tornadoes, answer the following ques- tions: Procedure • What precautions should you take if you are a 1 Use print and Internet resources to research mobile spotter tracking a storm with your car? answers to the first two questions below. • What safety measures should you take if you 2 Create a report that summarizes what you have are providing spotting information from a learned. Decide how you want to present your fixed position, like your home or school? report, whether as a poster, a mockup of a news- 3 The meteorologist wants recommendations for paper, a multimedia presentation, or a play. Be when and where to place her spotters this year. clear and concise when you are explaining the Use the maps she has given you from the National weather concepts involved in tornado formation. Severe Storms Laboratory on your “Where the Create tables, graphs, and/or illustrations to con- Tornadoes Are” handout to answer her questions: vey information in your report. • What time of year and in what areas would a 3 Use the maps on your “Where the Tornadoes Are” spotter be most likely to see a tornado? handout to answer Question #3. • What U.S. regions would you recommend against placing spotters? • What, if any, pattern do you notice regarding Questions the peak months for tornadoes throughout Write your answers on a separate sheet of paper. the United States? 1 The Warning and Coordination Meteorologist for • Hawaii and Alaska are not on the data charts your area first wants to make sure that you know you have been given. But the meteorologist enough about tornadoes to qualify to work as a wants to know whether to position spotters in spotter. Include the answers to these questions in either of these states. Based on what you have your report: learned about how tornadoes form, would you • What conditions do meteorologists look for recommend placing spotters in either of those when trying to identify the possibility of a states? Defend your reasoning. tornado forming? Hunt for the Supertwister Student Handout Where the Tornadoes Are

This graphic shows the months of peak tornado occurrence in the 48

Apr-Jun contiguous states. The Jun-Aug months shown are based Jun-Aug May-Jul Jun-Aug Jun-Aug on data collected from Apr-Jun May-Jul 1950–1991. Jun-Aug Source: NOAA National Jun-Aug May-Jul May-Jul Jun-Aug Severe Storms Laboratory May-Jul Jun-Aug Aug Jun-Aug May-Jul Apr-Jun Jun-Aug May-Aug May-Jul Apr-Jun Apr-Jun Jun-Aug May-Jun Apr-Jun Aug Apr-Jun- May-Jul Jul May-Jul Jan-Apr April-Jul Apr-Jun Apr-Jun Apr-Jun Mar-Jun Mar-May Jul-Sep Apr-Jun May-Jul Mar-May Mar-May

Mar-Jun Mar-May Nov Mar-May Nov Apr-Jun Mar-May Nov May-Jul

This graphic depicts the mean number of days per century with at least one F2 or greater tornado touching down in a grid (each grid has a spacing of 80 kilometers). Results are based on data 5 collected from 1921–1955 that includes more than 10,000 tornadoes listed by date, damage classification, and location of touchdown by county. 20 10 Source: NOAA National Severe Storms Laboratory/map by Concannon, Brooks, and Doswell, 2000. 30 5 10

30 25 20 15 10 5