Tornadoes

While tornadoes occur in many parts of the world, they are found most frequently in the United States. Tornadoes account for an average of 65 fatalities and 1,500 injuries nationwide each year. Tornadoes are typically spawned by powerful thunderstorms, but sometimes accompany tropical storms and hurricanes as they move onto land. Most tornado-related damage results from wind velocity and wind-blown debris, as well as large hail.

Though generally associated with the central United States, tornadoes occasionally occur in New York City. Such events can occur with little or no warning.

Know the Terms

  • Tornado: a violently rotating column of air, usually pendant to a cumulonimbus, with circulation reaching the ground. It nearly always starts as a funnel cloud and may be accompanied by a loud roaring noise. On a local scale, it is the most destructive of all atmospheric phenomena.
  • "Gustnado": A "gustnado" is a small, whirlwind which forms as an eddy in thunderstorm outflows. They do not connect with any cloud-base rotation and are not tornadoes. Since their origin is associated with cumuliform clouds, gustnadoes will be classified as Thunderstorm Wind events. Like dust devils, some stronger gustnadoes can cause damage.
  • Tornado Watch: issued when conditions are favorable for the development of tornadoes in and close to the watch area. Their size can vary depending on the weather situation. They are usually issued for a duration of 4 to 8 hours. They normally are issued well in advance of the actual occurrence of severe weather.
  • Tornado Warning: issued when a tornado is indicated by radar or sighted by storm spotters. They can be issued without a Tornado Watch being already in effect. They are usually issued for a duration of around 30 minutes.
  • Enhanced Fujita Scale: used to classify tornadoes and the damage they cause across the country. The Enhanced Fujita (EF) Scale measures the wind speeds and resultant damage of tornadoes based on 28 damage indicators and six classes of wind speeds.
    • EF0: wind speeds of 65 to 85 mph
    • EF 1: wind speeds of 86 to 110 mph
    • EF 2: wind speeds of 111 to 135 mph
    • EF 3: wind speeds of 136 to 165 mph
    • EF 4: wind speeds of 166 to 200 mph
    • EF 5: wind speeds of 200 mph or more

Know What to Do

Preparing for a Tornado

  • Designate an area in your home to take shelter in the event of a tornado as part of your household disaster plan.
  • Assemble an emergency supply kit.
  • Stay tuned to your local radio and television stations for the latest storm information.
  • Know the difference between a tornado watch and a tornado warning.
  • Learn tornado danger signs:
    • An approaching cloud of debris can mark the location of a tornado even if a funnel is not visible.
    • Before a tornado hits, the wind may die down and the air may become very still.
    • Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.

If a Tornado Strikes

  • Go to your basement or the lowest point of your residence. 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.
  • Get out of automobiles.
  • Do not try to outrun a tornado in your car; leave it immediately for safe shelter.
  • If you cannot find shelter, take cover in a ditch or other recessed area and cover your head with your hands. Do NOT take cover under an overpass or bridge.
  • Be aware of flying debris.
  • Mobile homes offer little protection from tornadoes. Leave a mobile home and go to the lowest floor of a nearby building or storm shelter.
  • Avoid places with wide-span roofs, such as auditoriums, cafeterias, large hallways, or shopping malls.

After the Storm

  • Watch out for fallen power lines and stay away from damaged areas.
  • Listen to the radio for information and instructions.
  • 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.
  • If you smell gas, do not turn on any appliances or switches. This includes using phones, flashlights, or a cell phone.
  • Clean up spilled medicines, bleaches, gasoline, or other flammable liquids immediately. Leave the buildings if you smell gas or chemical fumes.
  • Take pictures of the damage —to your home and its contents — for insurance purposes.

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