I’ve never heard the term “Bomb Cyclone” before, though apparently that’s what hit the Eastern Seaboard today. I actually love a good snowstorm when our house becomes the “sledding house.” Today, the wind is whipping and the snow isn’t fluffy. As soon as the wind dies down, it’ll be all-hands-on-deck to shovel and scrape.
But first, hot chocolate anyone?
What exactly is a ‘bomb cyclone,’ or bombogenesis?
When discussing the storm, some weather forecasters have referred to a “bomb cyclone.” Calling it a bomb sounds dire, but such storms are not exceedingly rare — there was one in New England recently.
What makes a storm a bomb is how fast the atmospheric pressure falls; falling atmospheric pressure is a characteristic of all storms. By definition, the barometric pressure must drop by at least 24 millibars in 24 hours for a storm to be called a bomb cyclone; the formation of such a storm is called bombogenesis.
Here is how it works: Deep drops in barometric pressure occur when a region of warm air meets one of cold air. The air starts to move, and the rotation of the Earth creates a cyclonic effect. The direction is counterclockwise in the Northern Hemisphere (when viewed from above), leading to winds that come out of the northeast — a nor’easter.
That’s what happened at the end of October, when warm air from the remnants of a tropical cyclone over the Atlantic collided with a cold front coming from the Midwest. Among other effects then, more than 80,000 customers in Maine lost power as high winds toppled trees.
A similar effect was occurring Wednesday, as warm air over the ocean met extremely cold polar air that had descended over the East. Pressure was expected to fall quickly from Florida northward. nytimes.com
Check out this cool image of the Bomb Cyclone from space by the NOAA and posted on The Verge.