Convection, an upward motion of air, helps produce thunderstorms. But it’s relatively rare to have convection within a winter storm as thunder and lightning are far more common during warmer seasons. However, when convection is strong enough and there is plenty of moisture available, a winter storm can produce thundersnow.
Video of thundersnow in Middle Island, Suffolk County, New York:
Thundersnow is an unusual weather phenomenon that is similar to a typical thunderstorm, but produces snow instead of rain. Regardless of its rarity, thundersnow still has the potential to be very dangerous due to lightning and high snowfall rates. A thundersnow’s calling card is heavy snow and rates of two to three inches per hour are not uncommon. Similar to thunderstorms, thundersnows usually have a relatively brief lifespan, but have the capacity to bury a location under several inches of accumulation with little warning.
The threat of lightning associated with thundersnow is also very real. Even though lightning is not as frequent in a thundersnow compared to a thunderstorm, there have been cases of people being struck by lightning during a thundersnow. In March of 1996, a man was struck during a blizzard in Minneapolis. Six years later, four teenagers in Caribou, Maine, were injured in February 2002 when lightning struck a hill they were sledding on.
Most people have never experienced a thundersnow in their lifetime and with good reason. On average, thundersnows develop only six times across the U.S. each year, with the greatest concentration in the Intermountain West, Plains and Great Lakes. Although rare, they have also been known to form throughout the Mid-Atlantic and Northeast as well.
Be prepared! Know Before™.
The WeatherBug – Earth Networks Team