I always marvel at the aquamarine blue of glacial lakes, having photographed many in Glacier National Park, not to far from Banff. For viewers who wonder about that water, it's the glacial action high up in the passes that create this; the ice crushes the granite to powder, and when the ice and snow melt the meltwater then brings the powder down to the lakes. There, that lightweight powder is suspended in the water and it reflects all the colors of the visible spectrum... except blue (and just enough green to make the water the gorgeous color in this gorgeous photograph). The color contrast with the rocks and snow is outstanding!