‘Thundersnow’ familiar in North Country, but elsewhere, too
By PAUL HETZLER
One of the perks of living in the eastern Lake Ontario snow belt, in addition to bragging rights—to everyone outside the Buffalo region at least—about snowfall amounts and winter-hardiness, is a phenomenon called thundersnow. (Turns out that needing a compass to cross your back yard and being able to snowshoe up to your second-story window don’t qualify as perks.)
It sounds like an awesome name for a snowmobile race, but it’s just a snowstorm with thunder and lightning thrown in. Worldwide it’s quite rare, but during lake-effect snowstorms in the Great Lakes region thundersnow events may occur as many as a few times per season. In most cases that season is winter. The British Isles, parts of Japan, and Halifax, Nova Scotia also get thundersnow.In the Iroquois, or Haudenosaune, tradition, the storytelling season comes to an end after the first thunder of the year. I don’t know what kind of a wrench wintertime thunder throws into the tradition, though. For those Haudenosaune who love storytelling (most, I assume), one good thing is that when lake-effect snow falls at a rate of four inches per hour, it makes a heck of an acoustic blanket. The sound of thunder during a snowstorm is muffled and only carries a short distance—a mile or so—unlike summer thunder, which might be audible for five to ten miles.
Lake-effect snow, of course, happens when cold air passes over an expanse of relatively warm water. Lake-effect events can produce exceptionally heavy rates, and thus accumulations, of snowfall. Thundersnow can also produce round lightweight ice pellets that look much like Styrofoam beads used in packing. They also feel like packing beads, except colder. These pellets are known as graupel, a German word meaning “packing pellets for beer coolers,” or something like that, I’m sure.
Lightning in winter is potentially as dangerous as it is in summer, except that not quite as many people are out swimming, golfing or picnicking. (I’m told that for parts of the Tug Hill Plateau this is not necessarily the case.) According to the National Lightning Safety Institute, lightning fatalities do occur during thundersnow. The winter of 1996 saw at least two lightning-caused deaths, and four teenagers sledding in Maine were struck in 2002. Because snow dampens the sound of thunder in a winter storm, people may not hear it until the lightning strikes are very close by.
Although the lake-effect snow regions of upstate New York see more than their fair share of thundersnow (and snow, deicing salt, snow, road closures, snow, snow, etc.), consider these facts: The World Meteorological Organization reports that Kampala, Uganda has on average 280 thunderstorms per year. And in the winter of 1971, Mt. Rainier, Wash. received 1,224.5 inches – 102 feet -- of snow. In light of this I’d say snow-belt residents have nothing to complain about. But then they don’t tend to complain anyway.
Safe travels to all during the holiday season, and remember to put on snow tires. All-season radials are only safe all season in climates where it never snows.
Paul Hetzler is a forester and Cornell Cooperative Extension of St. Lawrence County horticulture and natural resources educator.