leaving deposits of rock debris. The "U"-shaped cross section of the river valleys are a result of 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 North Cascades area. See also Geography of Washington (state) Geology of the Pacific Northwest References External links North Cascades National Park National Park Service Mix-up Peak weather: Mountain Forecast North Cascades Mountains of Washington (state) Mountains of Chelan County, Washington Mountains of Skagit County, Washington Cascade Range North Cascades National Park North American 2000 m summits