Snowspout
Definition
A winter waterspout, also known as a snow devil, an icespout, an ice devil, a snownado, or a snowspout, is an extremely rare instance of a waterspout forming under the base of a snow squall. Although usually weak, winter waterspouts have reached EF1 Intensity and have done some damage.
Note: The terms "snow devil" and "snownado" also are sometimes used to describe a different phenomena, a spinning vortex close to the surface with no “parent cloud” that is filled with snow. This vortex is more similar to dust devils in the warmer climates.
Formation
The term "winter waterspout" is used to differentiate between the common warm season waterspout and this rare winter season event. Very little is known about this phenomenon but for the formation of a winter waterspout, very cold temperatures need to be present over a body of water warm enough to produce fog resembling steam above the water's surface. This will set up the extreme lapse rates needed to support convective development. Temperatures are uniformly below freezing, and there is no liquid water in the parent cloud, only ice crystals and graupel.
Location
Snowspouts are most often seen over the North American Great Lakes region, specifically Ontario, Canada, and may be associated with Lake Effect Snow events.
