Saturday, June 22, 2019

Lake McDonald

I suspect this is the same beach I posted pictures from several years ago (Gravel Beach: Sept 2012), although there are several fairly similar beaches along this stretch of Going to the Sun Road. The lake seemed a little higher this year and was encroaching into the trees in a few places along the shore. I don't think the level of the lake is controlled - the outlet, McDonald Creek, appears to be free-flowing - but it makes sense flows and water levels would be higher in June than in September.

There was a neat little recurved spit - looked a response to winds blowing west down the lake.

Most of the bedrock in Glacier belongs to the Belt Supergroup (a very thick stack of very old Proterozoic sedimentary rocks). The red and green argillites are widespread and when eroded by time and glaciers, yield red and green gravel, which waves shape into these nice little beaches.

No comments: