David Alt and Donald Hyndman's "Roadside Geology of Washington" says that until about 12,000 years ago, Little Si was part of Mount Si. A glacier filled the Snoqualmie Valley, burying part of Mt. Si, and meltwater rushing along its edge sliced Little Si away from the main mountain.
As the smaller valley glaciers dwindled, the huge icefield that filled the Puget Sound basin dominated and pushed lobes back up the valleys towards the Cascades. East of North Bend, near Mount Si, I-90 swithchbacks to climb a few hundred feet. That's a terminal moraine of one of those side lobes of the big glacier.
It hurts my brain to think of that much ice.
Eric Sandbo - Jan 10, 2008 1:12 am - Hasn't voted
GlaciersDavid Alt and Donald Hyndman's "Roadside Geology of Washington" says that until about 12,000 years ago, Little Si was part of Mount Si. A glacier filled the Snoqualmie Valley, burying part of Mt. Si, and meltwater rushing along its edge sliced Little Si away from the main mountain.
As the smaller valley glaciers dwindled, the huge icefield that filled the Puget Sound basin dominated and pushed lobes back up the valleys towards the Cascades. East of North Bend, near Mount Si, I-90 swithchbacks to climb a few hundred feet. That's a terminal moraine of one of those side lobes of the big glacier.
It hurts my brain to think of that much ice.