Morse and Muir glaciers terminate at the head of Muir Inlet in Glacier Bay National Park and Preserve, approximately 53 miles (85 km) north of Gustavus, Alaska. Morse Glacier originates in the Alsek Range of the Saint Elias Mountains and extends south-southeast for 9 miles (14.5 km) to an exposed outwash plain. It was named in 1892 by Harry Fielding Reid in honor of J.F. Morse, one of his companions on a trip to the area in 1890. Reid had initially referred to it as the “West Tributary” of Muir Glacier. Muir Glacier begins about 9 miles (14.5 km) south of Mount Harris and flows south for 13 miles (20 km) to Muir Inlet, roughly 7 miles (11 km) northwest of White Thunder Ridge. It was named around 1880 after John Muir, an American naturalist who discovered the glacier during his 1879 trip to Alaska.

Muir Glacier, now about 0.4 miles (0.5 km) wide and 13 miles (21 km) long, was the main attraction for visitors until the mid-1980s. At that time, the glacier’s terminus was at tidewater, calving icebergs into Muir Inlet from a 200-foot (60 m) high ice wall. Since the Little Ice Age maximum position at Glacier Bay’s mouth around 1780, Muir Glacier has experienced rapid and well-documented retreat. In 1794, explorer Captain George Vancouver found most of Glacier Bay covered by an enormous ice sheet, estimated to be 3,900 feet (1,200 m) thick in some areas. By 1904, the glacier had “broken through the mountains” between Pyramid Peak to the west and Mount Wright and Mount Case to the east, reaching the entrance to Muir Inlet. Since then, the glacier has retreated more than 24 miles (38 km) from its 1904 position.

A dramatic retreat of Muir Glacier began in 1899, marked by high ice flow and calving rates. By 1979, the glacier flowed at about 6,000 feet (1,839 m) per year, or roughly 16 feet (5 m) per day. In 1993, it emerged from tidewater. Currently, the ice flow rate near the terminus is approximately 150 feet (46 m) per year, or 0.5 feet (0.15 m) per day. While the terminus position remains relatively stable, the glacier is thinning, and surface crevasses are generally absent in this region. The ice advances and retreats seasonally, depositing large mounds of sediment at the terminus. Read more here and here. Explore more of Morse and Muir Glaciers and Glacier Bay National Park and Preserve here: