Grand Tetons - view from Signal Mountain

Even the flat bits of the valley show the clear signs of past ice age activity. Notice the yellow depression in the landscape seen here from Signal Mountain? That's a kettle. Locally they're known as potholes. Really they're the places where chunks of ice broke off from receding glaciers. Then the ice chunks get buried in glacial out wash (the slush that washes back from the melting glacier). Finally the ice melts, leaving these little potholes in the plains.



Even the pattern of tree growth is a remnant from the ice age. The places where trees grow are where glaciers dropped a layer of porous matter that retains more moisture than the rest of the plains. Scrubby sagebrush grows on the dry bits, while runty trees can be supported by the more porous soil.

To forensic geologists this lake says all sorts of fascinating things about the ice age. I was too distracted by how pretty it is to pay attention to any of them.