Retrieved from [1] which states on their webpage "Photos by the Pinedale Ranger District of the Bridger-Teton National Forest" which is a PD source as it is a U.S. Government agency. Image from [2].

Slide Lake is actually in the northwestern area of the Gros Ventre Wilderness. A landslide in 1925 carried some 50 million cubic yards of debris down the side of Sheep Mountain, forming a dam and creating Slide Lake. Two years later, a flood washed out part of that natural dam and the downstream town of Kelly was destroyed. Today, Kelly is a historic site and the road to (and area around) Slide Lake has been cherry-stemmed into the Gros Ventre Wilderness as a designated National Geological Area. Updated info from [3]

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