Twin Sisters Mountain

Twin Sisters Mountain, called Kwetl’kwítl’ Smánit in Nooksack, is a twin-peaked mountain in Washington’s Cascade Range southwest of Mount Baker. Its two summits, South Twin and North Twin, rise above 7,004 and 6,644 feet, with glaciers on the northeast slopes and both peaks within the Mount Baker Wilderness. Separated from Mount Baker by the Middle Fork Nooksack River and drained by nearby creeks that feed the Nooksack, the mountain is especially significant for its geology. It consists largely of relatively unaltered dunite, an unusual ultramafic rock uplifted by major thrust faulting during Mesozoic tectonic collisions, and its reddish color likely comes from weathered iron- and magnesium-rich dunite.

Washington · United States