What’s a nor’easter?

Understanding nor'easters

If you ever experience a nor'easter, or listen to first-hand accounts of one, there's one element you're sure to encounter: wind. And lots of it.

A nor'easter receives its name from the northeasterly winds that accompany it, and these same winds are to blame for nor'easters that make landfall. Every time a nor'easter tears at shutters on coastal businesses, sends water soaring into sea-view homes or slams a ship with massive waves, these northeasterly winds are at work.

A nor'easter, which can stretch for thousands of miles, forms in an area of low pressure over the warm waters of the Atlantic Ocean. In the beginning, it looks similar to a hurricane, thanks to an eye in the center of its low-pressure system. However, as the nor'easter tracks an oceanic route offshore of the East Coast, the storm's already cool core experiences a drop in temperatures at higher levels of the troposphere (the lowest layer of the atmosphere, which reaches from the earth's surface to 11 miles or 17 kilometers skyward) and leaves its hurricane-like roots behind. Hurricanes rarely reach the Mid-Atlantic or New England region, while nor'easters are known for making landfall almost exclusively in the area [source: The Weather Channel].

And this is where the winds come in. Northeasterly winds can, and often do, alter the trajectory of a nor'easter. Instead of heading out to sea, these hurricane-force winds cause nor'easters to turn their fury inland. Depending on where the storm reaches the coast, it will produce rain, snow or a mixture of the two types of precipitation. If northeasterly winds direct the storm to hit west of New York City or Boston, it will likely bring rain. If it flows to the east of these cities, snow or sleet is usually expected [source: The Weather Channel].

A nor'easter can even come on the heels of a hurricane. In October 2012, in the wake of Hurricane Sandy, a nor'easter rattled the East Coast where it dampened efforts to restore power and aid victims [source: Edwards].

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