Whitney Glacier on Mount Shasta in northern California is the state’s longest glacier and its only valley glacier, ranking second in area and volume only to nearby Hotlum Glacier. It begins high on Misery Hill, descends northwest through a major icefall, and ends well below the saddle between Mount Shasta and Shastina. Measured in 1986 at more than three kilometers long and 126 feet deep, it also stood out for expanding rather than shrinking: surveys found it grew by about one-third between 1951 and 2002 as increased snowfall outweighed melting despite warmer regional temperatures. Scientists warned that continued warming would likely reverse that trend.