Alaska - 22 Hubbard Glacier

Hubbard Glacier is located in Wrangell–St. Elias National Park and Preserve in eastern Alaska and Kluane National Park and Reserve in Yukon, Canada, and named after Gardiner Hubbard. Before it reaches the sea, Hubbard is joined by the Valerie Glacier to the west, which, through forward surges of its own ice, has contributed to the advance of the ice flow that experts believe will eventually dam the Russell Fjord from Disenchantment Bay waters. The Hubbard Glacier ice margin has continued to advance for about a century. In May 1986, the Hubbard Glacier surged forward, blocking the outlet of Russell Fjord and creating Russell Lake. All that summer, the new lake filled with runoff; its water level rose 82 ft, and the decrease in salinity threatened its sea life. Around midnight on October 8, the dam began to give way. In the next 24 hours, an estimated 5.3 cubic kilometres of water gushed through the gap, and the fjord was reconnected to the ocean at its previous level. This was the largest glacial lake outburst flood in recorded history, It takes about 400 years for ice to traverse the length of the glacier, meaning that the ice at the foot of the glacier is about 400 years old. The glacier routinely calves off icebergs the size of a ten-story building. Where the glacier meets the bay, most of the ice is below the waterline, and newly calved icebergs can shoot up quite dramatically, so that ships must keep their distance from the edge of the glacier in Disenchantment Bay.