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Tornado Information


How Tornadoes Form

Before thunderstorms develop, a change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere.

Weak Tornadoes

  • 69 percent of all tornadoes
  • Less than 5 percent of tornado deaths
  • Lifetime 1-10+ minutes
  • Winds less than 110 mph

Rising air within a hethunderstorm updraft tilts the rotating air from horizontal to vertical.



Strong Tornadoes

  • 29 percent of all tornadoes
  • Nearly 30 percent of all tornado deaths
  • May last 20 minutes or longer
  • Winds 110-205 mph

An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.


Violent Tornadoes

  • Only percent of all tornadoes
  • 70 percent of all tornado deaths
  • Lifetime can exceed 1 hour
  • Winds greater than 205 mph

Safety Procedures

  • Develop a plan for you and your family for home, work, , school and when outdoors.
  • Have frequent drills.
  • Know the county in which you live, and keep a highway map nearby to follow storm movement from weather bulletins.
  • Have a NOAA Weather Radio with a warning alarm tone and battery back-up to receive warnings.
  • Listen to radio and television for information.
  • If planning a trip outdoors, listen to the latest forecasts and take necessary action if threatening weather is possible.