What Is a Nor'easter? The Science Behind the East Coast's Fiercest Storms

Nor'easters can strike the East Coast at almost any time of year, though they're most frequent and most violent between September and April. These storms can bury cities in feet of snow, whip winds to hurricane strength, and flood coastlines from the Carolinas to Maine, sometimes all in the same event. Nor'easters are one of the most consistently disruptive weather systems in North America, and understanding how they form explains why they hit the same stretch of coastline so reliably.

Where the Name Comes From

A nor'easter gets its name from the direction its winds blow from as it moves up the coast, out of the northeast. The term itself has surprisingly old roots, tracing back to 16th-century English sailing terminology used to name compass points, and it's been in regular American use since at least the 1830s. Its spelling has occasionally drawn strong opinions (one Maine resident spent decades campaigning against the "nor'easter" spelling as an affectation), but it remains the standard term used by meteorologists and the public alike.

How a Nor'easter Actually Forms

Nor'easters are extratropical cyclones, meaning they're powered by clashing air masses rather than warm ocean water the way hurricanes are. They typically form as a low-pressure system within about 100 miles of the coastline, somewhere between North Carolina and New Jersey, then track northeast, often reaching peak intensity near New England or Atlantic Canada.