The largest tidewater glacier in North America is named for Gardiner Greene Hubbard, the founding president of the National Geographic Society and one of the founders of the Bell Telephone Company. Your ship will make a slow transit of Disenchantment Bay, skirting the six-mile (10 km) face of the glacier, which reaches as much as 400 feet (130 m) in height. Hubbard is advancing, and in 1986 the ice blocked off the head of the bay and formed a huge freshwater reservoir dubbed the “Russell Lake.” In late fall that year, the ice wall gave way and released 1.3 cubic miles of water into the bay with a flow equal to 35 Niagaras. It is estimated that it could again block off the entry at some point, and possibly spill over into the adjacent river basin. Hubbard is generally very active in calving icefalls from its face, often in blocks the size of a ten-story building. The ice at the face began its journey from the mountains some 400 years ago. The resulting eruption of spray and the delayed thunder of the splash are one of the most memorable thrills of an Alaskan cruise.