The East Coast Is Bracing for a Winter ‘Bomb Cyclone.’ What Is That?

Weather terminology can be a bit scary at times. Terms like “arctic blast” and “typhoon” create some disturbing mental images. But as East Coast residents in the United States prepare for winter storm Grayson this week—the National Weather Service says the storm will bring strong, damaging winds and snow—they are hearing a new term and it might be the most terrifying of all: “Bomb Cyclone.”

Even in the often-hyperbolic field of weather prediction, that’s an eye-catching name, but what is a bomb cyclone? And how bad will it be if you’re in it’s path?

The answer, as with so many things when it comes to winter weather, is: It depends. A bomb cyclone is, essentially, a powerful low-pressure system that rapidly intensifies. If that sounds a lot like a hurricane, you’re not too far off. The ‘bomb’ part of the name refers to the phenomenon when the pressure inside a storm cell falls so quickly that it gives the storm explosive strength.

Technically, the term bomb cyclone comes from the scientific term “bombogenesis,” which is a storm that drops 24 millibars of pressure over 24 hours. And what forecasters are worried about with this one is the pressure levels could be on the same level as Hurricane Sandy. (Researchers say climate change can be blamed for these sorts of events.)

That means the potential for hurricane or tropical storm force winds is present—though the damage likely won’t be as bad as it was with Sandy. And it’s possible that this could be much ado about nothing, since slight shifts in the system’s placement could make huge differences in snowfall.

One thing’s clear, though. It’s going to be brutally cold no matter what happens with this storm. A new arctic blast is on its way down from Canada, so whether this bomb cyclone results in high winds, heavy snow, or people complaining the weather weenies blew the call again, you’re going to want to stay inside. In addition to hurricane-force winds and snow or sleet, temperatures could also drop 20 to 40 degrees below normal.