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Tornado Classifications

Tornadoes are classified by the National Weather Service three different ways:

Weak Tornadoes - Account for 69 percent of all tornadoes and are defined as a tornado with winds under 110 mph. Weak tornadoes last an average of 5 to 10 minutes and account for approximately 3 percent of all tornado deaths.

Strong Tornadoes - Account for 29 percent of all tornadoes and approximately 27 percent of all tornado deaths. Wind speeds range from 110 to 205 mph, and these tornadoes may last 20 minutes or longer.

Violent Tornadoes - Account for only 2 percent of all tornadoes but result in 70 percent of all tornado deaths. Wind speeds exceed 205 mph, and lifetimes can exceed one hour.

Tornado Classifications

Weak Tornado near Hodges, Texas

Weak tornado near Hodges, Texas (Charles Doswell, III, NSSL, Norman Oklahoma)

Violent Tornado near Cheyenne, Wyoming Violent tornado near Cheyenne, Wyoming (Peter Willing)
Violent Tornado, northeast Texas Photograph of a mile-wide violent tornado in northeast Oklahoma on April 26, 1991. Despite the size and destruction associated with this tornado, only one person was killed, which is truly amazing! (Jim Ladue)

'Tornadoes: Nature's Most Violent Storms' was developed by the National Oceanic and Atmospheric Administration (NOAA)/National Weather Service (NWS) in cooperation with the American Red Cross and the Federal Emergency Management Agency (FEMA). It is designed to assist in heightening public awareness and understanding the dangers associated with tornadoes. The package provides an introduction to tornadoes and their impact, discusses tornado development and occurrence, and describes safety information for homes, schools, places of work, and outdoors. In addition, basic environmental clues are presented.

Individual use of the pictures within these presentation must have prior approval from the credited source.
  How Do Tornadoes Form   How Do Tornadoes Form   Table of Contents   Environmental Clues   Environmental Clues  

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