What’s a ‘bomb cyclone,’ anyway? 5 things to know about storm blasting central U.S.

The Minnesota Star-Tribune via Associated Press

Forecasters say a “bomb cyclone” will hammer states from Texas to Minnesota this week with freezes, blizzards and flooding, USA Today reports.

Wait, a bomb cyclone?

Aren’t regular cyclones bad enough?

And what’s a “bombogenesis” effect?

Here’s what you need to know.

1. What’s a bomb cyclone?

Cyclones are large weather systems surrounding a low-pressure center, The Conversation reports. They’re pretty routine in autumn, winter and spring in the central and eastern United States.

In a bomb cyclone, or bombogenesis, the pressure at the center drops rapidly, an average of 24 millibars in 24 hours, according to the publication. That’s much more than the normal change of 10 to 15 millibars over any given week.

(A millibar is a measure of air pressure in the metric system, equal to various numbers of even more esoteric terms like pascals and dynes, mostly used in meteorology, the Encyclopedia Britannica says.)

2. Who coined the name bomb cyclone?

Is this some kind of hyperbolic millennial new-speak? Not really.

Frederick Sanders and John Gyakum — two famous meteorologists, or at least, famous to other meteorologists — coined the phrase in a 1980 scientific paper, The Washington Post says.

“Given their explosive development, it was an easy path to take to just call these systems ‘bombs,’” Gyakum said, according to the publication.

Gyakum said he and Sanders wrote the paper mostly to warn people about the dangerous storm systems that can hit outside the traditional hurricane season, the Post reported.

3. OK, so what happens in a bomb cyclone?

“The lower the pressure, the stronger the storm,” The Denver Post says. So bomb cyclones can get pretty wild.

Freezing temperatures, high winds, and heavy rain and snow — including blizzard conditions — are among the conditions to expect in a bomb cyclone, McClatchy reports. It’s kind of like a hurricane, except in winter.

“The name isn’t an exaggeration — these storms develop explosively and quickly,” Gyakum said, according to The Washington Post. “They can produce destructive winds, coastal flooding and erosion, and, of course, very heavy precipitation. If the term conveys the importance and the danger associated with them, then I think that’s a good thing.”

4. Have bomb cyclones happened before?

One hit the East Coast of the U.S. in January 2018, according to McClatchy. And a series of bomb cyclones in 1979 helped inspire the scientific paper that came up with the term, The Washington Post says.

5. What’s expected from this bomb cyclone?

Most bomb cyclones develop over the ocean from the clash of warm and cold air, but this one was spawned by a warm, subtropical air mass colliding with a cold Arctic one, The Denver Post says.

Forecasters expect a “ferocious mix of snow, rain and wind across the central United States,” USA Today reports. The storm has already snarled travel plans, with 1,200 flights canceled so far, and more than 100,000 people are without power in Texas.

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Don Sweeney has been a newspaper reporter and editor in California for more than 25 years. He has been a real-time reporter based at The Sacramento Bee since 2016.