WTTW News Explains: What Exactly Is Lake Effect Snow?


Between the wind, the cold, and the sun disappearing for what seems like months at a time, winter in Chicago is not for the faint of heart.

But it could be worse. We may be living in one of the snowiest cities in the U.S. Looking at that list, there’s a pattern.

They are all on the “wrong” side of a Great Lake. And by “wrong” we mean the side most likely to be covered in lake effect snow.

Oh yeah, the lake effect snow machine is real. It is unpredictable and capable of dumping tons of snow in a short amount of time.

And just because we’re on the “right” side of the lake, doesn’t mean we’re safe. When the wind turns over Chicago, be careful.

So what causes lake effect snow? Two things: cold air and relatively warmer water.

Here’s how it works: During a typical Midwestern winter, cold winds swoop in from the north, which, not to point fingers, usually means Canada.

The Great Lakes hold their heat longer than the surrounding land, so when this cold air passes over warmer water, it absorbs moisture like a sponge.

Depending on which direction the wind is blowing, there could be a lot of water going through. And the more water it passes through, the more moisture it collects.

When this hot, humid air mass hits the land and begins to cool again… WHAM-O! — lake effect snow.

The weirdest thing about lake-effect snow is how fast and furious it can fall in one spot, while the sun is shining just a mile or two away.

This is because, unlike large weather systems, lake-effect events tend to be hyperlocal.

So what’s stopping Chicago from being Buffalo?

Well, here, wind patterns typically flow west to east, pushing that moist, warm air toward Indiana and Michigan — sorry… not sorry.

But when do the winds change? It is then that the city gets a taste of the snow apocalypse.

Winter in Chicago: It could be worse…and sometimes it is. Thank you, lake effect snow!


What do you think?

Written by Natalia Chi

Chicago Popular; Chicago breaking news, weather and live video. Covering local politics, health, traffic and sports for Chicago, the suburbs and northwest Indiana.

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