Bow Lake and Peyto Lake are popular and beautiful stops on the IceFields Parkway north of Lake Louise. They are two more of the glacial fed lakes of varying shades of blue-green-aqua. The glaciers grind the rocks down to a fine powder called rock flour which is washed into the lakes by the meltwater. The silty water absorbs all of the colors of incoming light except the turquoise and blue of the sky that are reflected back to our eyes. Thus the colors of the lakes that we see change with the color of the sky.
Below is a photo of the alluvial fan where meltwater from the Peyto Glacier washes the rock flour into Peyto lake, causing the beautiful aqua color.