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    Tornado Facts
    Tornado Danger Signs
    Tornado Watches and Warnings
    Fujita Scale Damage Descriptions
    How to Prepare
    Safety Rules during a Tornado
    After a Tornado

 
Tornadoes are nature's most violent storms, with wind speeds inside the most violent tornadoes exceeding 300 miles per hour. This makes tornadoes very destructive and hence, very dangerous. The best way to be able to protect yourself and others from this destructive force is to know about it. This web page is designed with that purpose in mind.
 
Tornado Facts

A tornado on the ground
A tornado is a violently rotating column of air extending from a thunderstorm to the ground.

Tornadoes are capable of destroying homes and vehicles and can cause fatalities. Tornadoes may appear nearly transparent until dust and debris are picked up or a cloud forms in the funnel. The average tornado moves SW to NE but they have been known to move in any direction. The average forward speed is 30 mph but may vary from stationary to 70 mph and have rotating winds in excess of 250 mph. Tornadoes can accompany tropical storms and hurricanes as they move onto land. Waterspouts are tornadoes that form over water.

Tornadoes can occur at any time of the year. They have occurred in every state, but they are most frequent east of the Rocky Mountains during spring and summer months. In the southern states, peak tornado occurrence is March through May, while peak months in the northern states are during the late spring and early summer. Tornadoes are most likely to occur between 3 and 9 p.m. but can happen at any time.
 
Tornado Danger Signs
     Look for:

  A dark, often greenish sky,
  Large hail,
  A wall cloud, and/or,
  A loud roar, similar to a freight train.
    
A wall cloud formation
Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others. Before a tornado hits, the wind may die down and the air may become very still. A cloud of debris can mark the location of a tornado even if a funnel is not visible. Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.
 
Tornado Watches and Warnings
The National Weather Service (NWS) issues a tornado watch when tornadoes are possible in your area. Remain alert for approaching storms. This is the time to remind family members where the safest places within your home are located, and listen to the radio or television for further developments. A tornado warning is issued by NWS when a tornado has been sighted or indicated by weather radar. If a tornado warning is issued for your area and the sky becomes threatening, move to your pre-designated place of safety. Turn on a battery-operated radio and wait for further instructions. Forecasters and researchers use a wind damage scale created by T. Theodore Fujita to classify tornadoes and sometimes the damage done by other wind storms.
 
Fujita Scale Damage Descriptions
The Fujita Scale uses numbers from 0 through 5 and the ratings are based on the amount and type of wind damage. The scale had been calculated through F-12, which is Mach 1 - the speed of sound (750 mph) - but tornado wind speeds are not expected to reach these speeds; see the F-6 description below.

F-0 Gale tornado (40-72 mph): Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.

F-1 Moderate tornado (73-112 mph): The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.

F-2 Significant tornado (113-157 mph): Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.

F-3 Severe tornado (158-206 mph): Roof and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted.

F-4 Devastating tornado (207-260 mph): Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.

F-5 Incredible tornado (261-318 mph): Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel-reinforced concrete structures badly damaged.

F-6 Inconceivable tornado (319-379 mph): These winds are very unlikely. The small area of damage they might produce would probably no be recognizable along with the mess produced by F-4 and F-5 wind that would surround the F-6 winds. Missiles, such as cars and refrigerators would do serious secondary damage that could not be directly identified as F-6 damage. If this level is ever achieved, evidence for it might only be found in some manner of ground swirl pattern, for it may never be identifiable through engineering studies.

F-0 and F-1 tornadoes are considered "weak," F-2 and F-3 are "strong" and F-4 and F-5 are "violent." The National Weather Service accepted the Fujita Scale for use in 1973 and Allen Pearson, then director of the National Severe Storms Forecast Center, added the Pearson Scales for tornado path length and path width, creating the Fujita-Pearson Scale. A separate page contains a table of the complete Fujita-Pearson Scale.
 
How to Prepare
 When a tornado is coming, you have very little time to make life-or-death decisions. Advance planning and quick response are     the keys to surviving a tornado.
 Develop a plan for you and your family at home, work, school and when outdoors.
 The Federal Emergency Management Agency offers planning tips on its Internet site: www.fema.gov/pte/displan.htm.
 Identify a safe place to take shelter.
 Information on how to build a “Safe Room” in your home or school is available from the Federal Emergency Management     Agency at www.fema.gov/mit/saferoom.
 Conduct frequent tornado drills each tornado season.
 Keep a highway map nearby to follow storm movement from weather bulletins.
 Have a National Oceanographic and Atmospheric Administration (NOAA) Weather Radio with a warning alarm tone and     battery backup to receive watches and warnings.
 NWS watches and warnings are also available on the Internet. Go to the NWS Home Page at www.nws.noaa.gov for services     or weather.gov for weather and forecasts.
 Listen to radio and television for weather information.
 Check the weather forecast before leaving for extended periods outdoors. Watch for signs of approaching storms.
 If severe weather threatens, check on people who are elderly, very young, or physically or mentally disabled.
 Practice having everyone in your family go to your designated safe place in response to a tornado threat.
 Contact your local emergency management office and NOAA for more information on tornadoes.

Develop a communications plan
 Pick two places to meet: a spot outside your home for an emergency and a place away from your neighborhood in case you     cannot return home.
 Choose an out-of state friend as your “family check-in contact” for everyone to call if the family gets separated.
 Discuss what you would do if advised to evacuate.

Prepare a Disaster Supply Kit
 A 3-day supply of water (one gallon per person per day) and food that won’t spoil.
 One change of clothing and footwear per person.
 One blanket or sleeping bag per person.
 A first aid kit including prescription medicines.
 Emergency tools, including a battery powered NOAA Weather Radio and portable radio, flashlight, and extra batteries.
 An extra set of car keys and a credit card or cash.
 Special items for infant, elderly, or disabled family members.
 Copies of ID cards or driver’s licenses for all family members.

 
Safety Rules during a Tornado
 Do not get under an overpass or bridge. You are safer in a low, flat location.
 In a home or building, move to a pre-designated shelter, such as a basement (under a sturdy piece of furniture) or a Safe Room.
 If an underground shelter is not available, move to a small interior  room or hallway on the lowest floor and get under a sturdy piece of furniture.
 Put as many walls as possible between you and the outside.
 Stay away from windows. Go to the center of the room. Stay away     from corners because they attract debris.
 Get out of automobiles immediately and seek shelter in a nearby     building.
 If a building is unavailable or there is no time, get out of the car and lie     in a ditch or low-lying area away from the car.
 Be aware of potential for flooding. In urban or congested areas,      never try to outrun a tornado in a car or truck; instead, leave it     immediately for safe shelter.
 Tornadoes can change direction quickly and can lift up a car or truck     and toss it in the air.
 If caught outside, lie flat in a nearby ditch or depression and cover     your head with your hands. Be aware of potential for flooding.
 Be aware of flying debris. Flying debris from tornadoes causes most     fatalities and injuries.
 Mobile homes, even if tied down, offer little protection from     tornadoes.
 You should leave a mobile home and go to the lowest floor of a     sturdy nearby building or a storm shelter.
 Avoid places with wide-span roofs such as auditoriums, cafeterias,     large hallways, or shopping malls.
 Do not open windows, use time to seek shelter.
 Use arms to protect head and neck.

A bathroom left standing after destruction of the house
After the Tornado
 Help injured or trapped persons. Give first aid when appropriate. Don’t try to move the seriously injured unless they are in     immediate danger of further injury. Call for help.
 Stay out of damaged buildings. Return home when authorities say it is safe.
 Turn on radio or television to get the latest emergency information. Use the phone only for emergency calls.
 Clean up spilled flammable liquids immediately. Leave the building if you smell gas or chemical fumes.
 Take pictures of the damage – both the house and contents – for insurance purposes.

Inspect utilities in a damaged home
 Check for gas leaks – If you smell gas or hear a blowing or hissing noise, open a window and quickly leave the building. Turn off the gas at the outside main
    valve if you can and call the gas company from a neighbor’s home.
    If you turn off the gas, a professional must turn it back on.
 Look for electrical damage – If you see sparks or broken or frayed wires, or if you smell hot insulation, turn off the electricity
    at the main fuse box or circuit breaker. If you have to step in water to get to the fuse box or circuit breaker, call an electrician for advice.
 Check for sewage and water line damage – If you suspect sewage lines are damaged, avoid using the toilets and call a plumber.
    If water pipes are damaged, contact the water company and avoid using water from the tap. Melt ice cubes for safe water.

Mitigation
Mitigation includes any activities that prevent an emergency, reduce the chance of an emergency happening, or lessen the effects of unavoidable emergencies. Investing in preventative mitigation steps now, such as building a Safe Room, checking local building codes and ordinances about wind resistant designs and strengthening un-reinforced masonry, will help reduce the impact of tornadoes in the future.

You can print or download copies of FEMA publications from www.fema.gov/library. Order printed copies from FEMA’s DistributionCenter (800-480-2520). For Taking Shelter Before the Storm, call 888-565-3896.
 
This web page was developed using information resources obtained from the National Weather Service, Federal Emergency Management Administration, American Red Cross, and USA Today. Many thanks are due for their efforts in serving the public.
 
   
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