Off shooting birds around Pinedale, which made me think of ice!  Thought you might be interested. 

At the peak of the Pinedale glaciation, about 25,000 years ago, the Yellowstone ice cap was 4,000 feet thick over Yellowstone Lake.  Mt. Washburn’s summit, 2,400 feet above Canyon junction, has glacial striations proving that the ice dome flowed from south to north across the top of the Washburn range.  Pinedale glaciers formed the numerous Blacktail plateau moraines, created the giant ripples near Gardiner, carved the ice marginal channel known as Phantom Lake, and deposited the glacial till that accounts for the productive grasslands and wildlife of the Lamar Valley.