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Severe thunderstorms considered ‘destructive’ will trigger emergency alerts on cellphones: NWS

Photo: National Weather Service

Silver Spring, MD — Severe thunderstorm warnings from the National Weather Service will now be accompanied by a “damage threat” label, and NWS will activate emergency alerts on nearby cellphones for storms considered “destructive.”

According to an NWS press release, the three labels were developed as part of the Hazard Simplification Project, an initiative to better convey to the public the severity and potential impacts of thunderstorm winds and hail.

In order from highest to lowest damage threat, the labels are:
Destructive: Issued when winds are expected to reach 80 mph and/or baseball-sized hail (at least 2.75 inches in diameter) is possible. A wireless emergency alert will be sent to smartphones in the area.
Considerable: Criteria is at least 70 mph winds and/or golf-ball sized hail (at least 1.75 inches in diameter).
Baseline or “base”: Warns of 58 mph winds or greater and/or quarter-sized hail (1 inch in diameter). “When no damage threat tag is present, damage is expected to be at the base level,” the release states.


On average, about 10% of severe thunderstorms cross over the “destructive” threshold, according to NWS, which adds that 13 of the 22 costliest weather disasters last year were severe thunderstorms.

“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,” NWS states.

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