I don’t know what Muir thought of Yellowstone and the Tetons, but I bet he’d have found the Island Park area interesting: like Yellowstone, it’s got a fascinating geological history. For instance, Big Spring, near the northern end of Island Park, is indeed a big spring – one of the biggest in the world – and gives rise to Henry’s Fork of the Snake River.
More dramatically, the entire area occupies the floor of two nested caldera – collapsed volcanoes. The larger Island Park caldera is about the same size as the Yellowstone caldera, part of the supervolcano that – as the Onion jokes – could choose to blow at any minute.
Of course this relates to fatbiking! The Fat Pursuit course skirts the aligned western rims of the Island Park and smaller Henry’s Fork calderas, then runs south to the spot where the Henry’s Fork river drops off the edge of the caldera, forming the two Mesa Falls on its way to the Snake River. The course winds toward the eastern side of the Henry’s Fork caldera, climbing along its edge before dropping back down away from the rim to our first checkpoint. There the course starts to run north, climbing out of the Henry’s Fork again and then out of the Island Park caldera too on the way to our second checkpoint. Later, after the third checkpoint, the course bumps up and over the the rims again, just a few miles from the finish.
I doubt I’ll have the wherewithal (or the daylight) to notice these various encounters with the race’s geology, not maybe I can pick a few of the details up on the drive to the start in Thursday. And I’ll certainly hope that the super volcano doesn’t erupt while I’m riding in the race. That would almost certainly melt my bike and prevent me from racing the way I’d like.