Lake effect snow is produced in the winter when cold winds line up over long expanses of warmer lake water and then are uplifted by the orographic effect of the land on the downwind shores. This uplifting effect can produce narrow but very intense bands of precipitation.

Cold winds in the winter typically prevail from the west-southwest to the northwest producing the most dramatic lake effect snow falls on the northeast to south east shores of the United States' Great Lakes.

Similar snowfall can occur near large inland bays, where it is known as Bay effect snow.