These bighorn sheep are beside a naturally turquoise lake formed by glacial rock flour…Blue, frozen glacial ice…
Got Milk?. . .
The beautiful turquoise color shown in the photo is the true color of the water. Sometimes called “glacial milk”, the unusual color is due to the presence of “rock flour”, which consists of tiny clay particles formed as rocks stuck to the bottom and sides of a glacier grind against bedrock. This abrasion reduces some of the bedrock to a fine powder that looks like the flour used to make bread. As the ice melts this rock flour is exposed and transported away by meltwater, often into a nearby tarn.
They won’t settle down! . . . .
Meltwater also transports pebbles, sand, and silt into the lake, but these larger rock particles quickly settle to the bottom of the lake. In contrast, the much smaller particles of rock flour remain suspended in the water until the fall when the meltwater stops flowing or the lake freezes over. Only then does the water become calm enough to let rock flour settle to the bottom. A core sample from the middle of the lake would probably reveal alternating layers of silt and clay called “varves”. . . . One layer of each (varve) for every year the lake has been in existence.
Why so blue? . . .
Sunlight includes many different wavelengths of light ranging from the longer “reds” to the shorter “violets” (ROYGBIV). A white T-shirt is white because it reflects all of the wavelengths, a black shirt is colorless because it absorbs all of the wavelengths, and a red shirt is red because it absorbs the OYGBIV and reflects the R (red wavelengths). Apparently the tiny particles of rock flour suspended in the lake are just the right size to reflect more of the blues and some of the greens than any of the other wavelengths.
I mean, we really about ran into him. The trail went right beside him and it was very steep and bushy, no way to go up higher to get around him. Moose scare me a bit more than bears. Thankfully, it was not a mama with a calf. We all scurried quickly and quietly past this guy (9 kids along with my husband, my folks and myself) . The little kids kept on going up the trail while a few of us stayed behind and definitely kept our distance from him and took a couple of quick shots…
Not a very good picture above but I love the duck swimming next to him!
These closer ones were taken first and the more distant ones where taken later from across the lake.