St. Mary Lake, Glacier National Park —
Glacier-fed lakes all have this beautiful turquoise-like color to them. Having grown up in Minnesota I’m no stranger to lakes and their colors, but nothing compares to these glacier-fed lakes!
The color is caused by “glacier dust”, which is the result of the glacier grinding against the underlying rock. The rock gets pulverized into dust that is then swept into the lakes by glacial meltwater. The light reflected/refracted through the water picks up this beautiful hue. The visibility in the lakes is also quite low, and when standing on the shore you can only see a few feet before the water becomes an opaque sheet of turquoise.
As the glaciers disappear, this glacier dust will become a thing of the past, and these lakes will either dry up altogether, or remain but loose the unique colors. One of the small but tragic casualties of our rising temperatures.