Hubbard Glacier refuses to fade away

Submitted by Ned Rozell
Phone: 474-7468
01/17/08

As you read this, a rogue glacier is again threatening a small town.

Hubbard Glacier crept to within a football-field distance of ramming into Gilbert Point last June, and some scientists say that a spring 2008 closure of Russell Fiord "may be imminent." Roman Motyka, a research professor with the University of Alaska Southeast and the Geophysical Institute at the University of Alaska Fairbanks, gives Hubbard a 50-50 chance of plugging the entrance to Russell Fiord this spring.

Hubbard Glacier dips its tongue into salt water about 40 miles north of Yakutat, Alaska, home to about 600 people. Fed by fields of ice so immense that the glacier will rumble forward regardless of how warm the planet gets in the near future, Hubbard Glacier made headlines in 2002 when it bulldozed gravel into Gilbert Point, pinching off Russell Fiord’s link to the sea and creating the largest glacier-dammed lake in the world. Before the gravel dam broke, water within the lake rose more than eight inches each day and threatened to spill into a world-class steelhead stream near Yakutat.

Hubbard Glacier has been thickening and advancing since scientists first measured it in 1895. After the glacier dammed the fiord in 1986, the new Russell Lake rose 83 feet above sea level before the ice-and-gravel dam broke. In 2002, Russell Lake reached 49 feet above sea level before the dam burst and the water rejoined the ocean with a flood 30 percent greater than the largest measured flow of the Mississippi River at Baton Rouge.

If the plug of Hubbard Glacier again holds fast against Gilbert Point (as old river channels say it last did in about 1860), rainfall and glacial melt would fill Russell Lake until it reaches about 132 feet above sea level. Then, the water would spill over into an old channel of the Situk River, and flow from the river to the Gulf of Alaska. The Situk, now a clear-running stream with the highest population of wild steelhead in Alaska and possibly the world, would become a glacial stream that could be as large as the lower Snake River in Idaho.

More than 80 percent of Yakutat’s commercial and recreation fishing economies depend upon fish in the Situk River, according to information provided by the city and borough of Yakutat. Scientists including George Kalli of the U.S. Army Corps of Engineers in Anchorage estimate that a flood from Russell Lake could reduce steelhead populations in the Situk for perhaps 50 years.

Kalli and other scientists figure that Russell Lake would spill over about eight or nine months after Hubbard Glacier dams Gilbert Point. In a 2005 report, researchers with the Alaska District of the U.S. Army Corps of Engineers concluded that there is no cost-effective way to preserve the character of the Situk after Hubbard closes the door--rejected options included a tunnel dug through Gilbert Point, a seven-mile levee to force the overspill into a drainage other than the Situk, and the use of explosives to keep the salt-water channel open.

"The amount of explosives needed to impact the entire advancing face of the Hubbard Glacier would be quite large," the corps researchers wrote.

Adaptations for the people of Yakutat might include changes in the tourism base, and at least a temporary look at the resources of other streams in the area, said Kalli, who is now working on an economic study.

"Other fish runs from around Yakataga and Dry Bay may be able to take some of the brunt if they were to lose the Situk," Kalli said.

When the people of Yakutat will lose the Situk is an open question, one you can get an idea of by checking out a laser rangefinder scientists installed at Gilbert Point (http://www.glacierresearch.com). The rangefinder measures the distance from the face of the glacier to Gilbert Point.

"It’s pretty useful scientifically, and people in Yakutat can get on the Internet and see what the glacier’s doing," Kalli said.

This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Ned Rozell is a science writer at the institute. To view past columns or to subscribe, visit www.gi.alaska.edu/ScienceForum/index.html.