Severe Thunderstorm Risk Categories

The National Weather Service uses a risk category system to identify thunderstorm risks in an area. Those risks range from Thunderstorms to High and have numbers ranging from 1 to 5. Number 1 starts with Marginal. The Thunderstorms level doesn’t have an associated number. A thunderstorm isn’t considered severe until winds reach 58 mph, producing 1″ hail or contains a tornado.