One Michigan County Got 390 Inches of Snow in a Single Winter

If you’ve never spent a winter in the Upper Peninsula’s Keweenaw Peninsula, here’s the visual that’ll help: imagine a winter so snowy that the snowfall, stacked up, would be taller than a three-story building.

That happened in the winter of 1978–79. The Keweenaw — that crooked finger of land jutting up into Lake Superior at the top of the U.P. — recorded 390.4 inches of snow that season. That’s 32.5 feet. It’s believed to be the all-time snowfall record for the entire United States east of the Rocky Mountains. The annual average for the area, dating back to 1910, sits around 240 inches — already extraordinary by any reasonable definition of “extraordinary.”

The reason is Lake Superior. The Keweenaw juts directly into the biggest, coldest of the Great Lakes, and as cold winter air rolls across the open water, it picks up huge amounts of moisture and dumps it as lake-effect snow the moment it hits land. It’s the same mechanism that makes Buffalo’s snow famous — just turned up much louder.

Locals respond to the situation by leaning all the way in. Up on US-41 about three miles north of Mohawk, there’s a small roadside park with a 30-foot-tall snow gauge that visitors call the Keweenaw Snow Thermometer. It’s painted with hash marks like a giant ruler, with a moveable red arrow showing each winter’s total snowfall. The gauge is topped at the 390.4-inch mark from 1978–79. The Keweenaw County Road Commission updates the arrow each spring with the most recent winter’s total. It is, almost certainly, the world’s largest snow thermometer.