Blue ice sheet, 12 mi (19 km) long, 1.
5 mi (2.4 km) wide, and more than 100 ft (30 m) high. It flows from the southern half of the huge Juneau Icefield, which lies in the Boundary Ranges in southeastern Alaska, U.S. A relic of the Little Ice Age (1500–1750), it recedes 90 ft (27 m) a year. The adjacent Mendenhall Lake began to form about 1900 and is now 1.5 mi (2.5 km) long and 1 mi (1.6 km) wide.