How are severe thunderstorms identified by the National Weather Service?

Added: 2026-05-28

[00:00:00]Do you know what makes a severe thunderstorm severe? There are three specific criteria the National Weather Service uses to differentiate severe storms from regular run-of-the-mill thunderstorms. If a storm meets just one of those three criteria, it is classified and warned as severe. First, wind. If a storm is producing wind gusts of 58 mph or greater, that pushes it from strong to severe due to the high likelihood of damage. Number two, hail.

[00:00:29]Once a storm is capable of dropping hail 1-in in diameter or greater, that's about the size of a quarter, it's classified as severe. And number three, tornadoes. This is a no-brainer, but if a storm has produced a tornado, it is considered severe. Now, here in Southwest Idaho, as we saw this week, severe storms are usually because of strong damaging winds, but occasionally, we do see large hail and very rarely, a weak tornado. So, there you go. Not all storms are created equal, and now you know what sets severe storms apart from the rest.