Tornados Author R. T. Schindler

Tornados

• Author R.T. Schindler

Developers

• Developed by Randall Schindler while at Steven F. Austin University

• Distributed by the Supercourse Tornado Team, Harold Brooks, NOAA, Daniel Mccarthy, NOAA, Schaefer, NOAA

• Eric Noji, CDC, Scott Lillianbridge, Uni. Texas,

• Francois Sauer, Supercourse, Kansas City

• Faina Linkov, Mita Lovalekar, Ronald LaPorte, Supercourse Pittsburgh

• Doug Barrett, Janet Winterton, Fraser, Kevin Maney, USA Today

Purpose

• At the time of a tornado teachers need to present up-to-date information to students

• A group of Global Experts in meteorology and prevention from academia, education, and industry have banded together to distribute cutting edge tornado lectures to schools for free

• As the disaster evolves, new slides will be sent

Additional Lectures by world experts

Tornado History

• The “Tri-State Tornado” is the most violent tornado on record

• On March 18, 1925, the tornado formed in Missouri and traveled 219 miles across Illinois into Indiana

• The funnel was up to .75 miles across and traveled as fast as 73 mph.

• It killed approximately 635 people

First Tornado Forecast

• On March, 25 1948, Major Fawbush and Captain Miller determined that the conditions of the atmosphere just west of Tinker AFB, OK were suitable for tornado development. The first tornado forecast ever was issued. A few hours later, a tornado arrived causing significant damage to the base. However, no deaths and only a few injuries occurred because many had been warned by the tornado forecast.

Tornado

• A violently rotating column of air (vortex), hanging from a cumulonimbus cloud, with circulation that touches the surface of the earth

Supercell Storm

• Severe weather occurs as strong downbursts…large hail…occasional flash floods and weak to violent tornadoes

• Severe event almost always occur near the updraft interface typically in the rear (southwest) storm flank. Some of the supercells have the interface on the front of the southeast flank

• High predictability of occurrence of severe events once a storm is identified as a supercell

• Extremely dangerous to public

• Extremely dangerous to aviation

The Supercell

Tornado Facts

• Tornados can occur almost anywhere in the world

• Duration: a few minutes

• Diameter (Avg.): 0.4 km

• Length of path (Avg.): 6 km

• Funnel can travel from 0 mph up to ~70 mph, usually travels at 30 mph

• 99% of all tornados in Northern Hemisphere rotate counterclockwise

• Texas is #1 for frequency of tornados per year

• Between 1950 and 1995 Texas had 5,722 recorded tornados

• Risk of death in a tornado in Texas: 1 in 1,054,267

• Texas cost per person per year for tornados: $3.94

Tornado Myths

• A highway overpass is a safe place to take shelter under during a tornado

• Opening windows during a tornado will help balance the pressure between the inside and outside of the house and may prevent destruction of the structure

• One should seek shelter in the southwest corner of a house or basement.

Tornado Oddities

• Tornados are reported to routinely carry objects many miles and have:

• sucked the frogs out of a pond and dropped them on a town

• carried a necktie rack with 10 ties attached 40 miles

• carried a flour sack 110 miles from a mill

• Tornados also drive objects into other objects and have:

• Driven splinters into an iron fire hydrant

• Driven straw and grass into telephone poles

When Tornados Occur

• Anytime of the year- usually in the spring, summer, and fall

• Most tornados occur during late spring in the month of May

• Between the late afternoon and early evening is when most tornados are spawned

• The most dangerous time for formation during evening hours

Where Tornados Occur

• Tornado Alley covers the Great Plains states

Tornado Wind Speed

• In 1971, Dr. Fujita developed a way of measuring the winds of a tornado. He reasoned that there was a link between wind speed and the damage caused by a tornado. There are 6 categories of tornados (F0 – F5)

F0 Category

• (Weak) winds (40-72) mph , little damage

• Damage: tree branches snapped, chimneys toppled, signs torn down

F3 Category

• (Strong) winds: (158-206) mph, severe damage

• Damage: most trees uprooted, trains overturned, roofs torn off, walls demolished

F5 Category

• (Violent) winds: (261- 319) mph, incredible damage; rare

• Damage: bark peeled off trees, houses lifted off foundations, vehicles travel greater than 100 m through the air

Tornado Forecasting

• Meteorologists who predict tornado development analyze the current atmospheric conditions such as: air temp., barometric pressure, the locations of fronts, wind velocities, convection, etc. Probably the most useful tool a meteorologist can use to identify tornados is radar, specifically Doppler radar (WSR-88D)

Tornados on Radar

The Life cycle of a Tornado

• The “Life Cycle” of a tornado consists of four distinct stages.

• These stages were first determined during the Union City, OK tornado of 1973

• Most tornadic events are difficult to classify and may not exhibit stages that are obvious to the observer

• Sometimes events become unclear: one tornado weakens another appears, or single event?

• Tornados do not “skip” – gaps in damage path may indicate a temporary weakening in intensity

Beginning Stage: Tornado begins as a rotating wall cloud which quickly evolves into a funnel

• Beginning Stage: Tornado begins as a rotating wall cloud which quickly evolves into a funnel

Early Stage:

• Early Stage:

• Tornado funnel develops (may be transparent) and extends down from the cloud to the ground

Mature Stage: Tornado funnel reaches maximum width as well as maximum intensity then begins to shrink

• Mature Stage: Tornado funnel reaches maximum width as well as maximum intensity then begins to shrink

The Tornado Outbreak of May 3, 1999

• Severe thunderstorms move into Ok, TX, Ks and spawn estimated 70 tornados, most occurred in Oklahoma

• In Oklahoma 40 people killed, 675 injured

• Damage: $1.2 billion

• Largest tornado outbreak in Oklahoma history

• 1,780 homes completely destroyed

• 6,550 homes damaged

• Satellite image taken May 3, 1999 @ 645 CDT

• View from the air of a tornado path in Central OK

• Tornado near Amber, OK at 6:30 CDT

Microburst

• Microbursts are downdrafts from thunderstorms consisting of a narrow column of cool air traveling at high speeds which can cause damage similar to a weak tornado over a small area

Waterspouts

• A waterspout is a tornado that forms over a body of water, or a tornado that moves from land onto water

Storm Chasers

• Storm chasers are a group made up of meteorologists and scientists, as well as amateur observers who voluntarily put themselves in the path of a severe thunderstorm in order to hopefully observe a tornado and obtain photographs and scientific data.

Tornado Indicators

• A greenish colored sky associated with the thunderstorm (caused possibly by the scattering of light by particles in the sky)

• Mammatus clouds

• A sudden drop in barometric pressure

• Large hail of at least .75 in. diameter

• Strong winds > 60 mph

• Frequent and intense lightning

• A rotating wall cloud or a cloud that appears to hang from the sky

• A loud rumbling noise- seek shelter!

Mammatus clouds

• Mammatus clouds

Tornado Damage

• Tornados mainly cause damage by picking up something and throwing it through the air or hurling objects against something

Early Warning Systems

• The National Storm Prediction Center constantly monitors the weather and radars across the U.S. They are responsible for issuing tornado watches and warnings.

• Tornado Watch: a parallelogram is drawn around a 10,000 mi.^2 s area where the atmosphere seems to possess the conditions necessary for tornado development (severe thunderstorm)

• Tornado warning: a county has a thunderstorm which appears to have produced a tornado or someone has physically spotted a tornado, apparent funnel, or observed damage from what could be a tornado! SEEK SHELTER IMMEDIATELY!!

Early Warning Systems

Bibliography

• http//www.photolib.noaa.gov/

• http://www.nsl.noaa.gov/GoldenAnniversary

• http://www.srh.noaa.gov/oun/

• http://www.usatoday.com/weather

• www.nsl.noaa.gov/~doswell?a_tornado/atornado.html

• http://www.disastercenter.com/

• http://www.tornadoproject.com/

• Church C., Burgess D., Doswell C., Davies-Jones,R., ed. The Tornado: Its Structure, Dynamics, Prediction, and Hazards.

• American Geophysical Union Press: 2000

• Liu, Henry. Calculation Of Wind Speeds Required to Damage or Destroy Buildings. Publication within The Tornado