rock debris. The last glacial retreat in the Alpine Lakes area began about 14,000 years ago and was north of the Canada–US border by 10,000 years ago. The "U"-shaped cross section of the river valleys are a result of that recent glaciation. Uplift and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the Alpine Lakes Wilderness area. See also List of peaks of the Alpine Lakes Wilderness Geography of Washington (state) References External links Alpine Lakes Wilderness (Mt. Baker-Snoqualmie National Forest) U.S. Forest Service Garfield Mountain weather: Mountain Forecast Mount Garfield rock climbing: Mountainproject.com Mountains of Washington (state) Mountains of King County, Washington Cascade Range Mount Baker-Snoqualmie National Forest North American 1000 m summits