What makes a thunderstorm severe?

By Justin Logan - bio | email feedback

Jonesboro, AR (KAIT) - Many people think lightning makes a storm severe. In reality lightning is the second leading weather related killer, but that doesn't make a storm severe.  Neither does heavy rain, ominous skies or thunder. These are all found in a typical thunderstorm.

What does make a storm severe are winds of 58mph or greater along with large hail. Up until January 5th, 2010 the National Weather Service categorized hail as severe if it were the size of a penny or larger. Now they classify severe hail as a quarter or larger.

Why the sudden change? The National Weather Service conducted research and found that hail the size of pennies or three quarter inch in diameter did not cause much damage. When they changed the size to one inch in diameter or the size of a quarter, damage was more likely and severe weather warnings were taken more seriously.

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