What to Expect From the ‘Bomb Cyclone’ Set to Pummel the East Coast

Timothy A. Clary, Getty Images
Timothy A. Clary, Getty Images

We're just a few days into the new year, and a winter storm of historic strength is already churning up the East Coast. As The Washington Post reports, the weather event has the potential to be the most severe storm in decades to form over the waters east of New England at this time of year.

The storm is being described as a "winter hurricane" and a "bomb cyclone"—terms that rival "snowpocalypse." But it's more than just dramatic weather lingo. Unlike blizzards that form over land, this one is powered by the Atlantic Ocean and is expected to drop to Hurricane Sandy-level atmospheric pressure within 24 hours. As pressure decreases more rapidly, the storm grows more intense in a process called bombogeneis (hence the "bomb" part of "bomb cyclone"). If it follows current projections, the storm will blanket the coast in dense, fast-falling sheets of snow.

The storm is already blasting southeastern states with rare ice and snow, prompting winter storm warnings in northern Florida for the first time in years. As it makes its way up the coast, the system will continue to strengthen. By the time it reaches New England Thursday, it's expected to hit the region with 40 to 60 mph winds and up to a foot of snow.

While the exact trajectory remains unclear, everyone living near the northeast coast should be prepared to hunker down from late Wednesday to Thursday night. A winter storm warning has been launched for the New Jersey shore, parts of Long Island, and parts of Connecticut, and a winter storm watch is currently in effect in New York City. Major cities farther south and farther inland, including Philadelphia, Baltimore, and Washington D.C., could make it through the storm with little to no snow accumulation.

The bomb cyclone follows a wicked cold snap across the U.S. that's already claimed the lives of 11 people. Temperatures in the northeast have remained below freezing since Christmas, and the impending storm will bring even more frigid weather this week.

[h/t The Washington Post]

What is Lake-Effect Snow?

Tainar/iStock via Getty Images
Tainar/iStock via Getty Images

As you probably guessed, you need a lake to experience lake-effect snow. The primary factor in creating lake-effect snow is a temperature difference between the lake and the air above it. Because water has a high specific heat, it warms and cools much more slowly than the air around it. All summer, the sun heats the lake, which stays warm deep into autumn. When air temperatures dip, we get the necessary temperature difference for lake-effect snow.

As the cool air passes over the lake, moisture from the water evaporates and the air directly above the surface heats up. This warm, wet air rises and condenses, quickly forming heavy clouds. The rate of change in temperature as you move up through the air is known as the "lapse rate"; the greater the lapse rate, the more unstable a system is—and the more prone it is to create weather events.

Encountering the shore only exacerbates the situation. Increased friction causes the wind to slow down and clouds to "pile up" while hills and variable topography push air up even more dramatically, causing more cooling and more condensation.

The other major factors that determine the particulars of a lake-effect snowstorm are the orientation of the wind and the specific lake. Winds blowing along the length of a lake create greater "fetch," the area of water over which the wind blows, and thus more extreme storms like the one currently pummeling the Buffalo area. The constraints of the lake itself create stark boundaries between heavy snow and just a few flurries and literal walls of snow that advance onto the shore. The southern and eastern shores of the Great Lakes are considered "snow belts" because, with winds prevailing from the northwest, these areas tend to get hit the hardest.

The One-Day Record Snowfalls In Each State

Greenseas/iStock via Getty Images
Greenseas/iStock via Getty Images

Long after you’ve grown out of believing in magic, every thick, whirling snowstorm still seems to have been cast upon your town by a winter warlock (or Frozen’s resident ice queen, Elsa).

It’s also pretty magical when those inches of stacked snowflakes add up to a message from your manager telling you not to come into the office. In southern states like Georgia or Florida, sometimes all it takes is a light dusting.

But even those characteristically balmy places have hosted some serious snowstorms over the years, and David Cusick for House Method crunched the numbers to find out which ones made the record books. Using data from the National Centers for Environmental Information, Cusick created a map showing the one-day record snowfall for each state.

Florida finished in last place with a scant total of 4 inches, which occurred in Santa Rosa County on March 6, 1954. About two years before that, on January 14, 1952, Colorado had a staggering 76 inches—that’s more than 3 inches per hour—a national record that’s remained unchallenged for nearly 70 years.

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But other states have come close. The snowstorm that hit Colorado in 1952 wreaked almost as much havoc in California, whose record from the same day was 75 inches. And Washington saw 70 inches of snow in November 1955, beating its 52-inch record from 1935 by a full 18 inches.

Though Midwestern states have gained a reputation for harsh, snowy winters, their one-day record snowfalls are surprisingly moderate. The Illinois and Indiana records are 24 and 26 inches, respectively, both slightly lower than Ohio’s 30-inch snow day from 1901. In 1993, North Carolina bested Ohio’s record by 6 inches.

Wondering how your individual county’s record compares to the overall state one? Cusick created a map for that, too, which you can explore below.

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[h/t House Method]

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