I grew up thinking of the Great Lakes as just… big lakes. Pretty for a road trip, good for a postcard, nice in the summer. Then I started reading about them, and my jaw kept dropping. We’re talking about an inland sea so massive it has shipwrecks the size of skyscrapers, snowstorms it brews up all by itself, and enough fresh water to shock you when you see the number written down. So before your next trip up north, here are five true things about the Great Lakes that completely changed how I see them.
Did you know the Great Lakes hold about 21% of the world’s surface fresh water?
This is the number that stopped me cold. According to the U.S. EPA, the five Great Lakes together hold roughly 21% of the planet’s surface fresh water, and a staggering 84% of North America’s. Sit with that for a second: nearly one out of every five gallons of surface fresh water on Earth that you could theoretically scoop up is sitting right here in the middle of North America. Not in some remote corner of the globe, but a day’s drive from a huge chunk of the U.S. population. When people call them an “inland sea,” they’re not being dramatic. They’re being accurate.
Did you know there’s a simple trick to remember all five lakes, and it spells a word?
If you’ve ever blanked on naming all five Great Lakes, here’s the fix that’ll stick with you forever: HOMES. Each letter is a lake. H is Huron, O is Ontario, M is Michigan, E is Erie, and S is Superior. That’s the whole set. I learned this mnemonic once and have never forgotten it since, which is more than I can say for most things I learned in school. So the next time someone tries to stump you, just picture the word HOMES and rattle them off. Bonus party fact: Lake Michigan is the only one of the five that lies entirely within the United States. The other four are shared with Canada.
Did you know Lake Superior is the largest freshwater lake on Earth by surface area?
Superior earns its name. At about 31,700 square miles of surface, it’s the single largest freshwater lake in the world by area, roughly the size of the entire state of South Carolina. You could drop Austria into it and have room to spare. It’s so big it behaves less like a lake and more like an ocean, complete with its own weather. And here’s the part that gives me chills: Superior is cold, deep, and famous for never giving up its dead. The frigid water slows the natural decay process, which is exactly why so many of its shipwrecks have stayed eerily preserved at the bottom for decades.
Did you know the Great Lakes were carved out by a glacier, leaving roughly 35,000 islands behind?
The Great Lakes aren’t ancient in geologic terms. They were born about 14,000 years ago, when a colossal glacier that had buried most of Canada and the northern U.S. finally retreated. As that mile-thick ice ground its way north, it gouged out enormous basins in the land, and as it melted, meltwater pooled into the valleys it left behind. The hilltops that stayed above the waterline? Those became islands, about 35,000 of them scattered across the five lakes. So every time you see one of those rocky little islands poking out of the water, you’re looking at a hilltop that a glacier didn’t quite manage to drown.
Did you know the Great Lakes are “non-tidal,” but they make their own snow and their own mini-tsunamis?
Technically, the Great Lakes do have tides, but they’re so tiny, under two inches, that scientists officially call them “non-tidal.” The real action comes from two wilder phenomena. First, seiches: when strong wind and pressure shove all the water toward one end of a lake, then quit, the water sloshes back and forth for hours like water in a giant bathtub, sometimes swinging levels by several feet. Second, lake-effect snow: when frigid Canadian air blows across the relatively warm lake water, the air soaks up moisture like a sponge and wrings it out as ferocious snow on the downwind shore. That’s why one town can get buried under feet of snow while another a few miles away stays nearly bare. The lakes are quite literally making their own weather.
Send this to the friend who’s done a Great Lakes road trip… they’re going to want to plan another one immediately.
