What the Hell Is a Bombogenesis?

via NASA/MODIS Rapid Response System.

If you live on the east coast of North America, you may have noticed that Old Man Winter took a giant dump on your doorstep today. The polar vortex we survived two weeks back seemed like it would be the most metal-sounding meteorological event of the season, but it turns out today's snowstorm is called a “bombogenesis.” So far, this year's weather is turning out to be a real boon for band names.

So, what the hell is a bombogenesis anyway? It's a rapidly intensifying storm, characterized by a drop of at least 24 millibars in barometric pressure over a 24 hour period. During the 1940s, meteorologists began referring to these storms as “bombs” because they are such rapid onslaughts of winter savagery. Indeed, they are often confused with hurricanes because they produce hurricane-force winds.

Approximate areas in which extratropical cyclones form. Photo via Titoxd.

Bombogenesi—I'm assuming that's the plural—develop when a cold air mass meets a warm one. Together, they conceive a devil baby that becomes an extratropical surface cyclone. The cold core of this mid-latitude cyclone is what powers the trademark intensity of the storm, and gives it its “bomb” characteristics. According to Jeff Haby of the Weather Prediction, “many Nor'easters are the product of bombs.”

The bombogenesis currently bearing down on the East Coast is the result of a second polar vortex reacting against the balmier air masses above continental North America. The edge of the storm has already touched down in Tennessee, but the “bomb” part is revving up off the coast of Virginia as you read this sentence.

It will hit the East Coast this afternoon (Tuesday), causing heavy snowfall until the the late evening, around 8 PM. But even if the wintery mix eases up early, it will be replaced by freezing temperatures and high winds. Philly.com has estimated what kind of snowfall major Eastern seaboard cities should expect here.

As Brian Merchant reported when the last polar vortex graced us with its icy presence, these extreme weather incidents are likely related to climate change. Indeed, if you'll recall, a bombogenesis hit the East Coast around the exact same time last year. As Andrew Freedman of Climate Central wrote back then, “Climate studies have shown that extratropical storms in the Northern Hemisphere are shifting their paths northward as the climate warms, and there has been a trend toward stronger Arctic storms in recent years.” So basically: suck it up, because more bombs are likely on the way.

Tokyo in the middle of last year's bombogenesis. Photo via Jun Seita.

Oh, and by the way, if you don't live near the North Atlantic and think this doesn't affect you—no dice. These Arctic blasts can develop in the Midwest United States, as well as in the Pacific Ocean. For example, Japan was hit with a bombogenesis on steroids in mid-January 2013. The barometric pressure dropped an insane 49 millibars in 24 hours. Tokyo ended up being particularly hard-hit by the storm: two people were killed, 1600 were injured, and some poor guy's house was decimated by an ice-chunk that fell off the 634-meter tall Tokyo Skytree.

If you live thousands of miles from any coastline, however, you can relax as you probably won't have to deal with bombogenesi. Just the usual crippling droughts and hellish wildfires. You lucky dogs.