Have you ever been in the middle of a strong thunderstorm and wondered why a “warning” has not been issued? Believe it or not, there is an official “definition” for Severe Thunderstorms used by the National Weather Service. In order for a thunderstorm to be classified as “severe”, it must contain one of the following: hail of at least 1 inch diameter, winds over 57 mph, or a tornado.
Heavy rain potential alone does not determine a storm’s official severity status, even though excess water can certainly lead to problems. Lightning intensity is also not a factor in the issuance of Severe Thunderstorm Warnings. This is one reason that every thunderstorm must be treated with respect, regardless of whether a formal warning has been issued or not. Lightning kills over 50 people each year in the United States, and hundreds more are injured. Many of these injuries occur when people refuse to take shelter. Remember the old rule- if you can hear thunder, you are close enough to be hit by lightning.