Moraine Lake, in the Valley of the Ten Peaks, shows a strong blue hue that changes with the seasons and light. Refraction of light off rock flour deposited by glacial meltwater produces the lake's tint. Rising sharply from the lakehore, the surrounding peaks help to provide the lake's unique tint by contributing to the ongoing supply of glacial material. The surface elevation of the lake varies with the year; it rises most in mid-to-late summer when glacial melt is strongest. Thousands of years ago, glaciers deposited the moraine that creates the natural dam producing the lake; its composition helps filter the water entering the lake. Ancient rock formations spanning millions of years contribute varied mineral compositions to the lake's waters from the surrounding watershed. Rare forms of phytoplankton that flourish in these cold, mineral-rich waters are among the unusual alpine species supported by the lake's environment.
