What makes a storm severe?

KNOXVILLE, Tenn. (WVLT) -- You might have dealt with some nasty storms recently. Linda said a storm must be severe, and was wondering why there wasn't a warning.

There is a criteria for a severe thunderstorm warning to be issued. The National Weather Service needs indications of hail that is at least one inch *or* wind gusts of at least 58 miles per hour.

The reason lightning isn't included in a severe thunderstorm threshold is because any storm would then be included. Lightning can be deadly and can cause some serious damage, but is not a part of the Severe Thunderstorm Warning criteria.

Heavy rainfall can also cause problems, but it is not included in a warning. There are several levels of flooding alerts, that would cover the threats caused by the heavy rain.