Yale 360: When Rocky Mountain explorer Walter Wilcox hiked up to Bow Summit in Canadas Banff National Park in 1896, he took a photo of a turquoise lake that later caught the eye of a National Geographic magazine editor. In the photo, which was eventually published, the glacier feeding the lake was just a mile upstream.
Since then, the snout of Peyto Glacier has receded more than three miles from the broad valley it carved out thousands of years ago. Remnants of ancient tree trunks the glacier bulldozed...