Damaging Thunderstorm Winds

Many times when storm damage occurs to buildings, trees or other objects, people automatically say it was a Tornado! The “glamour” of having a tornado seems to overwhelm scientific evidence and common sense.  Although difficult for many to understand, in most years, thunderstorm winds cause more damage, and are more frequent than tornadoes. In addition, property and crop damage can be more severe from thunderstorm winds than from tornadoes. Thunderstorms winds can exceeded 100 mph while the most common tornado winds are generally not this strong.

Thunderstorm winds come in many forms, sometimes from squall lines of thunderstorms and other times in the form of downburst winds.  The most frequently encountered type of damaging straight-line wind in a thunderstorm is that associated with the leading edge of the rain-cooled outflow, known as the gust front.  Although most thunderstorm outflow winds range from 30 to 50 mph, on occasion these winds can exceed 100 mph.  Downburst-producing storms often give little advance indications of the imminent danger on weather radar or to the spotter, so warnings are difficult to issue.

 In 2004, thunderstorms winds produced an estimated $5.5 million in property damage, according to the publication Storm Data. This was about 1/6th the amount of tornado damage in 2004. However, in most years, thunderstorm wind damage is more than that caused by tornadoes.

To be safe from strong thunderstorm winds, go inside a sturdy building but stay away from windows that could break. If available, get to a basement or underground shelter. Large hail and flooding rains may accompany strong winds, so be alert to these dangers, also. Stay informed about the weather at all times!

 The following FEMA graphic illustrates how winds damage buildings.


MARCH 13-17,  2006

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