Explaining the National Weather Service’s new ‘destructive’ thunderstorm category

Severe thunderstorm categories

MADISON, Wis. — As of August 2nd, the National Weather Service is now using a new designation for severe thunderstorms they say will help better describe the severity and potential impacts from those storms.

To do that, the NWS developed three new categories for the threat of damage: base, considerable and destructive.

The “base” category refers to the baseline criteria for a severe thunderstorm warning, which remains the same it has always been: a storm that includes 1 inch (quarter-sized) hail and/or winds of at least 58 mph. This category of storms will not activate a Wireless Emergency Alert to your phone, and you can expect the damage to be at base level if your thunderstorm warning does not include a damage threat tag.

The “considerable” damage threat level has a minimum criteria of 1.75-inch hail (golf ball-sized) and/or 70 mph winds. This level will also not activate a Wireless Emergency Alert, according to the NWS.

However, if a storm carries the “destructive” damage threat tag, it will trigger a WEA alert to your phone if you are in the affected area. In order to meet that criteria, a storm needs to have at least 2.75-inch hail (baseball-sized) and/or 80 mph winds.

The National Weather Service says only 10% of all severe thunderstorms across the entire country reach that destructive level each year. They hope the new designations will help warn people when urgent action is needed and when a life-threatening storm is happening.