Lower Curtis Glacier is in North Cascades National Park in the U.S. state of Washington. Named for photographer Asahel Curtis, the glacier is in a cirque on the western slopes of Mount Shuksan. Lower Curtis Glacier is rapidly retreating and has a negative mass balance, meaning that the rate of snow and ice that is falling in the accumulation zone is less than that which is lost each year in the ablation zone. Between 1908 and 1984, the glacier experienced a loss of thickness by 45 meters (147 ft). Between 1984 and 2002, the glacier lost another 6 meters (19 ft) in thickness.