National Weather Service to include new “destructive” criteria, improving call-to-action for certain storms


Debris litters weather-damaged properties at the intersection of County Road 24 and 37 in Clanton, Ala., the morning following a large outbreak of severe storms across the southeast, Thursday, March 18, 2021. (AP Photo/Vasha Hunt)

SILVER SPRING, Md. (WDHN) – The National Weather Service will soon update its warning criteria for severe thunderstorms, providing you with more information on the most serious of storms that may cause “destructive” or “considerable” damage.   

You will continue to receive a WEA, or Weather Emergency Alert, on your smart phone for life-threatening events such as tornadoes and flash floods.

Beginning July 28, the National Weather Service will begin including a “damage threat” tag to Severe Thunderstorm Warnings, a change in the way the government’s weather forecasting agency has handled these types of warnings in the past.

Severe thunderstorms, by definition, include winds in excess of 58 mph or hail of at least one-inch in diameter.  If NWS meteorologists believe a severe thunderstorm contains 2.75 (baseball size) inch diameter hail and/or 80 mph winds, a warning will receive a “destructive” damage threat tag.  These events will automatically trigger a Wireless Emergency Alert for the warned area. If your phone is set up to receive a WEA, you will receive a notification of that warning immediately. 

Thunderstorms with 1.75 (golf ball size) inch hail and/or 70 mph winds will be given a “considerable” damage threat criteria that will show up in the text of the warning; however, a WEA will not be triggered for this particular category.

“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 a WEA to your cell phone,” the National Weather Service said.

Example of a WEA notification you would receive on your smartphone if a severe thunderstorm is deemed “destructive” by NWS meteorologists, beginning July 28.

Roughly, 10 percent of all severe thunderstorms reach the “destructive” level each year in the United States. More than half of the costliest weather disasters in the country last year were caused by these severe thunderstorms, NWS said. A WEA would have automatically alerted those in the path of those destructive storms.

Through preparedness, the National Weather Service hopes the updated severe thunderstorm warning threshold and communication will provide a timely call-to-action to the imminent dangers posed by Mother Nature and, in turn, save lives.

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