Tornado Safety for Citizens

Tornadoes can occur in any state, but are more frequent in the Midwest, Southeast and Southwest. The states of Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Mississippi, Nebraska, Oklahoma, South Dakota and Texas are at the greatest risk, due to being in what's known as "Tornado Alley."

A tornado is defined as a violently rotating column of air with circulation reaching the ground. It is spawned by a thunderstorm or sometimes as a result of a hurricane. It is produced when cool air overrides a layer of warm air, forcing the warm air to rise rapidly. The damage from a tornado is a result of the high wind velocity and wind-blown debris. Tornado season is generally March through August, although tornadoes can occur at any time of the year. They tend to occur in the afternoons and evenings, with over 80% of all tornadoes striking between noon and midnight.

Know Your Terms! (courtesy of The National Weather Service)

  • Tornado Watch: Issued by the NWS when conditions are favorable for the development of tornadoes in and close to the watch area. They are usually issued for a duration of four to eight hours and are normally issued well in advance of the actual occurrence of severe weather.
  • Tornado Warning: Issued when a tornado is indicated by the WSR-88D radar or sighted by spotters; therefore, people in the affected area should seek safe shelter immediately. They can be issued without a Tornado Watch being already in effect and usually issued for a duration of around 30 minutes.
  • Tornado Emergency: An exceedingly rare tornado warning issued when there is a severe threat to human life and catastrophic damage from an imminent or ongoing tornado. This tornado warning is reserved for situations when a reliable source confirms a tornado or there is clear radar evidence of the existence of a damaging tornado, such as the observance of debris.

Be Prepared!

  • Make a disaster kit;
  • Make a family emergency plan -
    • Practice a family tornado drill at least once a year;
    • Plan places where your family will meet, both within and outside your immediate neighborhood if you are separated;
    • Identify an out-of-town contact to call to let them know you are okay and can pass that information on to other family members;
    • Identify your shelter in case of a tornado warning -
      • A storm cellar or basement provides the best protection;
      • If you do not have an underground shelter, go to an interior room or hallway on the lowest floor;
      • Stay away from windows, doors and outside walls;
      • If you are in a vehicle, get out and lie flat in a ditch or other low-lying area, using your hands and arms to protect your head. DO NOT get under an overpass or bridge. The winds can pull you out from underneath it.
  • Listen to radio or TV stations for information;
  • Make sure your pets are safe if you can't bring them into the shelter with you;
  • Opening windows does not keep a house or building safe from exploding due to low air pressure during a tornado. It actually increases the chance of high winds entering and causing more damage to your home and exposing you to injury.

After the Storm:

  • Make sure the danger has passed before coming out of your shelter;
  • Stay with your family. Don't wander away, as it is easy to get disoriented due to street signs being gone and landmarks destroyed;
  • Watch for broken glass, nails and other sharp objects;
  • Stay away from downed power lines - they could still be live;
  • Avoid using matches and/or lighters - flammable gas may be leaking from damaged gas lines;
  • Contact your insurance agent and advise them of any damage;
  • Do not use generators, grills, camp stoves, or other gas, propane, natural gas, or charcoal-burning devices inside your home, basement, garage or camper, or outside near an open window, door or vent. Carbon monoxide can build up and poison the people and animals inside;
  • Use battery-powered lanterns for light;
  • Cooperate fully with public safety officials.

Enhanced Fujita Scale

ScaleWind Speed (Miles Per Hour)Wind Speed (Kilometers per hour)Relative FrequencyPotential Damage
EF-065 to 85105 to 13553.5%
  • Minor or no damage.
  • Peels surface off some roofs; some damage to gutters or siding; branches broken off trees, shallow-rooted trees pushed over.
EF-186 to 110138 to 17831.6%
  • Moderate damage.
  • Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken.
EF-2111 to 135179 to 21810.7%
  • Considerable damage.
  • Roofs torn off well-constructed houses; foundations of framehomes shifted; mobile homes completely destroyed; large trees snapped or uprooted; light-object missiles generated; cars lifted off the ground.
EF-3136 to 165219 to 2663.4%
  • Severe damage.
  • Entire stories of well-constructed homes destroyed; severe damage to large buildings such as shopping malls; trains overturned; trees debarked; heavy cars lifted off the ground and thrown; structures with weak foundations are badly damaged.
EF-4166 to 200267 to 3220.7%
  • Extreme damage.
  • Well-constructed and whole frame houses completely leveled; cars and other large objects thrown and small missiles generated.
EF-5> 200> 3220.1%
  • Total destruction.
  • Strong-framed, well built houses leveled off foundations and swept away; steel-reinforced concrete structures are critically damaged; tall buildings collapse or have severe structural deformations.

This table is from Wikipedia.