North Cascades National Park, Washington – July 2018

As one of the signs at Diablo Lake explains: “As glaciers in the surrounding high country slowly wear down the mountains, the grinding of rock against rock produces a fine silt that meltwater streams carry into the lake below. This “rock flour” suspended in the water reacts with light to give the lake its blue-green color.” I have seen this effect of rock flour in water elsewhere, but North Cascades National Park takes the cake in its intensity. Gorgeous!!