For others:
This is Spirit Lake.
It lies around
four miles north of Mt. St. Helen's. When Ol Helen blew her top, she blew down probably millions of trees for a long way around, and those trees wound up in Spirit Lake. The log jam (for lack of a better word) is about 2.5 miles long, and just under a mile across at it's widest.
Other smaller lakes around the area also have log jams (small one in the upper left of the pic), but not on a scale like this. The surrounding hills have an astounding number of fallen trees. It's well worth wandering around the area on GoogleEarth.