Peyto Lake, Canadian Rockies. Situated in a deep glacial valley below Bow Summit along the Icefields Parkway in Banff National Park, the waters of Peyto Lake take on a brilliant aquamarine color every summer as meltwater from glaciers flows into the lake with its burden of ground-up glacial silt. Suspended in the water of the lake, this milky solution absorbs the light at the short end of the visible-light spectrum causing the water to appear blue green.