National Weather Service To Unveil Damage Threat Categories for Severe Thunderstorm Warnings

By Benjamin Cox on July 30, 2021 at 1:31pm

The National Weather Service is launching new weather warning categories to better reflect the strength of an incoming storm.

Starting on Monday, forecasters will be adding damage threat categories to any severe weather warnings which include the labels “considerable” and “destructive” damage.

State Climatologist Trent Ford says the labels should give the public a clearer picture of what’s coming in a potential storm system: “For example, we know that if an EF-0 tornado hits an area, it is unlikely to cause significant damage as to completely destroy a mason or kind of traditional wood structure home, but an EF-4 tornado can. That means perhaps different actions for different people, so what the National Weather Service is doing because of technological advances in radar and communication. Now, what they said they are going to do is along with a severe thunderstorm warning, we are going to give an idea of what that thunderstorm’s strength is or what the potential damage is.”

The “considerable damage” warning label may include golf ball sized hail and/or 70 mile per hour winds. The “destructive damage” warning label may include potentials of baseball sized hail and/or 80 mile per hour winds. The criteria for a baseline or “base” severe thunderstorm warning remains unchanged.

According to the National Weather Service’s announcement, only 10% of all severe storms reach the destructive category each year, nationwide. Most of these storms are damaging wind events such as derechoes and some of the larger, more intense thunderstorms, called “Supercell” storms that can typically produce very large hail in their path. The new destructive thunderstorm category conveys to the public urgent action is needed, a life-threatening event is occurring and may cause substantial damage to property. Storms categorized as “destructive” will trigger emergency weather alerts on cellphones.

WLDS/WEAI is a National Weather Service reporting station.