Future Tense

Winter Starts With a Bang, Thanks to Glorious Lake-Effect Thundersnow

Earlier this afternoon, Chris Zimmer of Mentor, Ohio, was in the right place at the right time to capture one of the rarest, most intense winter weather phenomena there is: thundersnow. Watch, and be amazed:

Thundersnow happens only in particularly powerful snowstorms with especially strong updrafts. The sound of thunder in thundersnow is dampened, too, by all the snowflakes—you’ve got to be nearly underneath it to hear it.

Early-season lake-effect snowstorms fit the bill, with the still warm-ish water giving an extra boost of energy to the cold Arctic air pushing southward from Canada. These snowstorms can behave more like summer thunderstorms and produce snowfall rates up to 2 or 3 inches—sometimes even more—an hour in narrow bands along the immediate shoreline. The effect is maximized when the wind direction is more or less in line with the orientation of the lake (for example, a due north wind over Lake Michigan).

The National Weather Service office in nearby Cleveland called today’s event a “mega-band” and reports that 10 to 12 inches have already fallen in isolated areas near the shore of Lake Erie. The next several days could feature quite a bit more of the same. The Omega Block pattern that’s currently in place across North America favors continued blasts of Arctic air for the East, and as long as the north winds keep blowing, the lake-effect snow machine will keep on cranking. Here’s the outlook, via NOAA’s Weather Prediction Center, which is calling for “the threat of unusually-high amounts of accumulation”:

A very prolonged period of local lake-effect snowfall events will prevail at various times across all 5 Great Lakes. With significant snows already present, hard to imagine how much more snowfall is possible. Prolific numbers are possible. Anomalous? Certainly.

How prolific are we talking? Well, the unofficial New York state snowfall record—nearly 12 feet in eight days—was set back in 2007 thanks to a particularly intense lake effect event. Now, nothing like that is expected this time around. (It would be impossible to forecast such a localized phenomenon this far in advance anyway.) Still, we’re talking feet for whoever finds himself in the sweet spot. The exact locations of lake-effect snows are notoriously fickle to forecast more than a few hours in advance—there can even be clear skies just a few miles away!—but one thing’s for certain: The upcoming pattern will produce a lot of shoveling somewhere.

By far the most famous encounter with thundersnow was courtesy of the Weather Channel’s Jim Cantore on Feb. 1, 2011, in Chicago:

By the way, Washington, D.C., and New York City are expecting their first snowfalls of the season Thursday night—thankfully, just an inch or so.