Severe thunderstorms can be life-threatening but not all severe storms are the same. Hazardous conditions range from tornadoes, large hail storms,and widewspread straight-line winds called derechoes to cloud- to-ground lightning and flash flooding.
Starting August 2nd the National Weather Service will better convey the severity and potential impacts from thunderstorm winds and hail by adding a "damaging threat" tag to Severe Thunderstorm Warnings, similar to our Tornado and Flash Flood Warnings.
"Destructive" and "Considerable" Damage Threat Catagories.
We developed three catagories of damage threat for Severe Thunderstorm Warnings.
The Catagories, in order of highest to lowest damage threat, are destructive, considerable and base.
These tags and additional messaging are designed to promote immediate action, based on the threats.
The criteria for a Destructive damage threat is at least 2.75 inch diameter hail (baseball size) and or 80 mph thunderstorm winds. Warnings with this tag will automatically activate a Wireless Emergency Alert on smartphones within the warning area.
The Criteria for a"considerable" damage threat is at least 1.75 inch diameter (golf ball sized hail and or 70 mph thunderstorm winds. This will not activate a WEA Wireless Emergency Alert. When no damage threat tag is present, damage is expected to be at base level. The criteria for a baseline or "base" severe thunderstorm warning remains unchanged. 1.00 inch (quarter-sized hail and or 58 mph thunderstorm winds.
This will not activate a WEA Wireless Emergency Alert when no damage threat tag is present, damage is expected to be at least base level.