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Hubbard Glacier

From its source on Mount Logan in the Yukon territory, Hubbard Glacier stretches 76 miles to the sea north of Yakutat in Disenchantment Bay. It is the longest tidewater glacier in America, with an open calving face over six miles wide. 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 1986, the glacier temporarily closed the connection between Russell Fjord and Disenchantment Bay (for a review of this event, visit the USGS web site). In spring 2002, the glacier again approached Gilbert Point. It pushed a terminal moraine ahead of its face and closed the gap again in July. On August 14, the terminal moraine was washed away after rains had raised the water level behind the dam it formed to 61 feet above sea level. (See the photo gallery for images of the 2002 advance and 2003 and 2004 activity.)

The Hubbard continues to advance and retreat seasonally. The Forest Service, National Park Service, and U.S.Geological Service continue to monitor its activity.

After a fairly static year in 2003, Hubbard picked up speed the last two springs. On May 3, 2004, the gap was estimated at 640 feet (195 meters). Last year, the gap closed from 1350 feet (410 m) in February to 660 feet (200 m) by mid-May. Monitoring continues and updates will be posted from time to time.

Last year's progression is documented in the 2006 update.

Hubbard is one of a type of glacier found in the United States only in Alaska - a tidewater glacier. These glaciers calve when giant pieces of ice crack off the head of the glacier and fall into the sea. Hubbard's calving has produced the slurry of ice seen in the foreground of the photo above as well as the growing mass of ice bergs collecting behind the constriction at the head of Russell Fjord/Lake.

While the faces of most glaciers advance very slowly if at all, Hubbard is an exception. Fast glacier flow fascinates glaciologists, who met in Yakutat in mid-June 2002 for an international symposium on fast glacier flow, a timely and well-placed meeting.

USDA Forest Service - Tongass National Forest
Last Modified: November 21, 2007