Severe Weather Safety

Tornados

Although tornadoes occur in many parts of the world, they are found most frequently in the United States. You can find statistical information on tornadoes at www.spc.noaa.gov and local information at Douglas County Emergency Management.

Tornado Facts

  • A tornado is a violently rotating column of air extending from a thunderstorm to the ground.
  • Tornadoes may appear nearly transparent until dust and debris are picked up or a cloud forms within the funnel. The average tornado moves from southwest to northeast, but tornados have been known to move in any direction.
  • The average forward speed is 30 mph but may vary from nearly stationary to 70 mph.
  • The strongest tornados have rotating winds of more than 250 mph.
  • Tornados can occur at any time of the year.
  • Tornadoes have occurred in every state, but they are most frequent east of the Rocky Mountains during the 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 summer.
  • Tornadoes are most likely to occur between 3 p.m. and 9 p.m. but can happen any time.
  • Before thunderstorms develop, a change in wind direction and an increase in wind speed with increasing height create an invisible, horizontal spinning effect in the lower atmosphere.
  • Rising air within the thunderstorm updraft tilts the rotating air from horizontal to vertical.
  • An area of rotation, two to six miles wide, now extends through much of the storm. Most tornadoes form within this area of strong rotation.

Safety

It is important to remember that any thunderstorm can produce a tornado with little or no warning. When a tornado warning is issued or you hear the outdoor warning sirens anytime other then the scheduled test days, seek shelter and tune into local radio, television, or your NOAA weather radio for instructions and information (to purchase a NOAA weather radio visit Douglas County Emergency Management Web Site).

When it comes to tornado safety, there is no fool proof measure that can guarantee your safety. However, by following the safety tips listed below, your chances of survival are greatly increased.

Before a tornado strikes

  • Look for approaching storms which may include a dark greenish tint to the sky, contain large hail, and produce a loud roaring noise of rushing wind.
  • Monitor NOAA All Hazard Radio for the latest updates.

Where to go when a tornado warning has been issued

  • If all else fails remember – DUCK – Down to the lowest area, Under something sturdy, Cover your head, and Keep in shelter until the storm passes.

Myths and Truths

Myth: Areas near lakes, rivers, and mountains are safe from tornadoes.
Truth: No place is safe from tornadoes. A tornado near Yellowstone National Park left a path of destruction up and down a 10,000 foot mountain.

Myth: The low pressure with a tornado causes buildings to “explode” as the tornado passes overhead.
Truth: Violent winds and debris slamming into buildings cause most structural damage.

Myth: Windows should be opened before a tornado approaches to equalize pressure and minimize damage.
Truth: Leave the windows alone. The most important action is to immediately go to a safe shelter.

Myth: If you are driving and a tornado is sighted, you should turn and drive at right angles to the storm.
Truth: The best thing to do is to seek shelter at the best available shelter. Many people are injured or killed when remaining in their vehicles.

Myth: People caught in the open should seek shelter under highway overpasses.
Truth: Take shelter in a sturdy reinforced building if at all possible. Overpasses, ditches, and culverts may provide limited protection from a tornado, but your risk will be greatly reduced by moving inside a strong building.

Are You Ready for a Tornado (PDF, 156KB) – provided by American Red Cross, NOAA, and Federal Emergency Management Agency (FEMA).

Be Prepared

Each year, many people are killed or seriously injured by tornadoes and severe thunderstorms despite advance warning. Some did not hear the warning, while others heard the warning but did not believe it would happen to them. Once you receive a warning or observe threatening skies, YOU must make the decision to seek shelter before the storm arrives. Develop a plan for you and your family at work, school, and when outdoors. It could be the most important decision you will ever make.

Here are a few sites to help you develop a Preparedness Plan:

Back: Floods and Flash Floods

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Back: Thunderstorms and Lightning

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Sources: Douglas County Emergency Management, National Oceanic and Atmospheric Administration (NOAA), and Federal Emergency Management Agency (FEMA)