A nor'easter is a powerful storm that strikes the northeastern coast of the United States, bringing heavy snow, rain, and fierce winds. The name comes from the direction the winds blow during the storm: from the northeast, off the Atlantic Ocean toward the land.

These storms typically form when cold air from Canada collides with warm, moist air from the Atlantic. The result can be dramatic: blizzards that dump several feet of snow, coastal flooding from high waves and storm surge, and winds strong enough to knock down trees and power lines. Major nor'easters have shut down entire cities, closed schools for days, and left millions without electricity.

The northeastern United States experiences several nor'easters each winter, though most are relatively mild. The biggest ones become legendary: the Blizzard of 1888 buried New York City under 50 inches of snow, while more recent storms like the Blizzard of 1996 paralyzed the entire East Coast. People in Boston, New York, and other coastal cities know to stock up on supplies when forecasters predict a major nor'easter is coming.

The term is sometimes spelled northeaster or written with an apostrophe as nor'easter.