What you're looking at is the view of Mount
Rainier from the terminous of the Emmons Moraine Trail. "The trail begins at the White River Campground's western edge and proceeds one mile upvalley. Turn left on the moraine trail at a signed junction.At the trail junction a prominent moraine rises before you.
It was formed by a glacial advance during Garda Age sometime before 1660, when trees began growing on its flanks. It is one of the most conspicuous geologic features in the (White River) valley.
From the moraine crest look across the valley to the former height of the ice, defined by a distinctive "trimline." It curls downvalley to
the terminal moraine that's also marked by the limit of forest vegatation." - Carolyn L. Driedger from her book, "A Visitor's Guide to Mount Rainier Glaciers."