Thundersnow

Thundersnow, also known as a winter thunderstorm or a thundersnow storm, is a thunderstorm in which snow falls as the primary precipitation instead of rain. It is considered a rare phenomenon. It typically falls in regions of strong upward motion within the cold sector of an extratropical cyclone. Thermodynamically, it is not different from any other type of thunderstorm, but the top of the cumulonimbus cloud is usually quite low. In addition to snow, graupel or hail may fall as well. The heavy snowfall tends to muffle the sound of the thunder so that it sounds more like a low rumble than the loud, sharp bang that is heard during regular thunderstorms. Thundersnow can occur during a normal snowstorm that sustains strong vertical mixing which allows for favorable conditions for lightning and thunder to occur. It can also occur from the lake effect or ocean effect thunderstorm which is produced by cold air passing over relatively warm water; this effect commonly produces snow squalls over the Great Lakes.