extreme weather

Last week, from Windigo up here to Snug Harbor, lake levels climbed multiple feet in just a few minutes. Beaches were covered, canoes were set adrift. Several minutes later, the water dropped away again, taking logs and branches and canoes away with it.

In the Visitor Center, we were flooded with questions. “What was that strange current in Tobin Harbor?” “This giant rock was suddenly underwater, and a few minutes later it was uncovered again! That’s how much the water rose! What was up with that?” A number of people asked about the “tide.” Some people didn’t want to admit how difficult paddling in Tobin had been, but when they heard us start talking about the weird rushes of water, they leaped to chime in.



The basics of what's happening during a seiche.



The explanation, of course, was a giant seiche that rocked across the lake; water essentially tipping, as if in a giant bowl, from one side to another. Major storms in Duluth (and we're talking major; flooding was so extreme that the polar bear escaped from his enclosure at the zoo and had to be re-captured) sent strong winds repeatedly in the same direction, literally pushing water away from Duluth and towards Isle Royale. Windigo experienced the most severe water level changes, as the seiche hit them first. For the next 24-36 hours, seiches of declining strength came and went, like water sloshing back and forth in that proverbial bowl.

Then came the storms - a night of cracking thunder and nearly constant lightning, dumping multiple inches of rain on the island overnight. The following afternoon, everyone's radios leaped into attention simultaneously, with a warning from Houghton of "extreme and severe weather," "winds upward of 60 mph," "frequent lightning." Everyone sprang into a kind of delighted, frenetic activity at the excitement. We battened down the hatches, triple-lined the boats. I pictured angry winds screaming lengthwise up the island from Windigo, where just that morning there'd been reports of a boat sinking at the dock. Visitors were all dispatched indoors. The sky turned slate-gray and the whole harbor began to rumble with constant thunder, sounding remarkably like we were trapped inside the stomach of an extremely hungry giant.

Of course, as these things normally are, the whole storm was a bit of a let-down. It whizzed in with streaks of lightning over the channel and a few minutes of torrential rain, and then whizzed right by again, with nary a down tree in its wake. It wasn't until the next morning that the waves picked up and disappointed visitors had to eschew their canoe trips.

The stormy few days' greatest legacy was the state it left the trails in: having a current, and supporting aquatic life. It's only now, the third day of sun, that you can finally just about go for a hike without your snorkel.