Extreme winter weather mean bomb cyclones could happen. What are they? : NPR

Cars slowly travel through an intersection after a second round of snow storm passed through northern Minnesota Thursday, Dec. 15, 2022, in Duluth, Minn.

Holden Law/AP

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Holden Law/AP

Cars slowly travel through an intersection after a second round of snow storm passed through northern Minnesota Thursday, Dec. 15, 2022, in Duluth, Minn.

Holden Law/AP

Extreme winter weather, such as subzero temperatures, wind chills and heavy snow, is impacting much of the U.S. this holiday weekend, and is expected to heavily impact travel and mail deliveries, and could even be deadly in some regions.

The intense conditions are piquing interest in the meteorological term “bomb cyclone.” Google searches for the term over the last seven days peaked Wednesday.

What is a bomb cyclone?

A bomb cyclone, also known as bombogenesis, is defined by a rapidly intensifying storm. That can happen when atmospheric pressure drops significantly, which is usually the result of warm and cold air masses overlapping, according to the National Ocean Service.

Where are they likely to happen this weekend?

Places across the northern Rockies, northern Plains and upper Midwest are experiencing temperature drops by tens of degrees in minutes.

The extremely cold airmass is expected to hit at least 24 other states along the Gulf Coast and in the eastern U.S., causing some coastal flooding and creating flash-freeze conditions on roadways across the central and southern plains, the National Weather Service said.