Hubbard Glacier (Alaska)

Hubbard Glacier is located in eastern Alaska (USA) and partially of Yukon (Canada). It has a length of 122 km (76 ml). Icebergs sized as a 10-story building routinely break off. The glacier enters Disenchantment Bay with most of its ice being below the waterline. Newly broken off icebergs are constant danger for cruise ships visiting the region, so the vessels must keep their distance from its edge in the bay.

Before it reaches sea, Hubbard Glacier is joined by Valerie Glacier to the west, which has contributed to the advance of ice flow that experts believe will dam Russell Fjord from the waters of Disenchantment Bay. For about a century, Hubbard Glacier ice margin continues to advance. In May 1986, the glacier surged forward, blocking Russell Fjord's outlet and creating "Russell Lake." The lake filled with runoff and its water level rose 25 m (82 ft). The decrease in salinity threatened sea life. Around midnight on October 8, 1986 the dam began to give way and during the next 24 hours, 5.3 cubic km (1.3 cu miles) of water gushed through the gap. The fjord was reconnected to ocean at the previous level. This was the 2nd largest glacial lake outburst flood in recorded history, and had equivalent flow of 35 Niagara Falls.

On May 20, 2002 Hubbard Glacier squeezed towards Gilbert Point. The longest source for the glacier originates 122 km (76 ml) and is approx 8 km (5 ml) west of Mount Walsh (3,4 km / 2,1 ml altitude). A shorter tributary glacier starts at the easternmost summit on Mount Logan ridge (at 5,6 km / 3,5 ml).

In spring 2002, Hubbard Glacier again approached Bert Point, pushing a terminal moraine ahead, then closing the opening in July. On August 14, the moraine was washed away after rains raised the water level behind the dam it formed to 18 m (60 ft) above sea level. The fjord could be dammed again, next time probably permanently. If this happens, it could overflow its southern banks and drain through Situk River, threatening a local airport.