Lake-Effect Snow Setup for Great Lakes

Lake-effect snow is caused by rapid destabilization of the air combined withadditional lifting produced by friction and terrain. Arctic air masses becomeextremely unstable when the lowest levels pick up some heat from the relativelywarm water. This creates the initial boiling and overturning of the air, whichthen causes bands of snow-producing clouds to extend downwind. When the flowreaches land, the air slows due to friction, and a piling-up effect increasesthe lift. Upward motion is enhanced even more as the elevation of the terrainincreases.Putting it all together gives everything necessary for the blinding lake-effectstorms that have been known to dump a foot of snow in just a few hours. Due tothe tremendous instability in the atmosphere, these lake storms are oftenaccompanied by lightning and thunder.

Story by AccuWeather.com Meteorologist Meghan Evans.