Canada’s Banff National Park is filled with stunning mountain peaks capped with glaciers and snow. The steep, rugged mountains are the source of beautiful, turquoise streams that feed alpine lakes.
The turquoise water is interesting. As glaciers move, they polish the underlying rock, producing very fine particles of dust called rock flour. The rock flour mixes with the water traveling downstream. The color is a result of light reflecting around the densely packed dust in the water. On bright days, with the sun in the right position, the river displays the brilliant turquoise. If the sky is more cloudy, the water will be a milky off-white. When it reaches the lakes, the rock flour eventually settles out. But, if the river is filling the lake quickly, the lakes can be turquoise also.
The mountainside on this image from Kootenay National Park is beautifully colored. But the coloring is deceptive. The rust color is dead conifers. The black is foliage that was consumed by fire. Many of the conifers died due to pine beetle infestation.
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