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% of all tornadoes
• Less than 5% of tornado deaths
• Lifetime 1-10+ minutes
• Winds less than 110 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 2% of all tornadoes
• 70% 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/parish 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.