Mendenhall Glacier is a glacier about 13.6 miles long located in Mendenhall Valley, about 12 miles from downtown Juneau in the southeast area of the U.S. state of Alaska. The Mendenhall Glacier ice caves are among the world’s most stunning, with their eerie, swelling blue domes that resemble the underside of a rapid river, flash-frozen.
The Mendenhall Glacier is a tongue of ice stretching 12 miles from the Juneau Icefield to Mendenhall Lake. At its widest point, the glacier is more than a half mile wide, with ice 300 to 1,800 feet deep. The Mendenhall is one of 38 large and more than 100 smaller valley glaciers in the Juneau Icefield.
Glacial ice has a unique crystalline structure that absorbs and reflects light, giving the ice its blue appearance. The most intense blue occurs in crevasses and when ice breaks off, or calves, from a glacier’s face. The blue color fades as the ice is exposed to air and the crystalline structure breaks down. In Alaska, glacier viewing is often best on overcast and rainy days.