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New thunderstorm alerts will soon pop up on your phone: Here’s what they mean

Base? Considerable? Destructive? The new phone alerts from the National Weather Service are designed to provide warnings on the seriousness of upcoming storms.

A severe thunderstorm watch was issued for the Chicago Area.
How strong is an incoming thunderstorm? New alerts from the National Weather Service will provide better clarity on a storm’s severity and potential impact.
Sun-Times file photo

The National Weather Service started a new system this week to better categorize the severity of incoming thunderstorms and providing clarity on the potential impacts of those storms.

Launched Aug. 2, the NWS added a “damage threat” tag to its severe thunderstorm warnings, similar to the ones that already accompany its flash flood and tornado warnings. The tag categorizes the storm and is “designed to promote immediate action, based on the threats,” a NWS statement said.

The “damage threat” tags have three different categories to denote the severity of the storm: base, considerable and destructive.

What do the new tag categories mean?

The NWS defines the three tag categories as such:

  • A base storm produces 58 mph winds and/or 1-inch sized hail. If no damage tag is added to a severe weather alert, the category should be expected to be base level.
  • A considerable storm will have winds at 70 mph and/or hail measuring 1.75-inch diameter.
  • Destructive storms will have winds at 80 mph and hail measuring about 2.75 inches in diameter, or about the size of a baseball. This storm tag will immediately trigger a Wireless Emergency Alert on all smartphones within the area.

Only storms with the destructive tag will result in a Wireless Emergency Alert, the NWS said. Further details on these categories are available here.

How can I get NWS alerts?

The NWS sends out Wireless Emergency Alerts through mobile carriers. You do not need to sign up for these alerts and most smartphones have been supporting these capabilities since 2012.

“Alerts are sent automatically to WEA-capable phones during an emergency,” the NWS said.

More information on these alerts is available here.