Alaska's Speeding Glacier

By MICHAEL D. LEMONICK.

The first person to report that something was amiss was Guide Mike Branham, 40, a strapping six-footer who each spring flies a pontoon plane full of bear hunters into a cove on Russell Fjord, in Alaska's southeastern panhandle. This year he discovered that things had changed: Hubbard Glacier was on the move -- at a most unglacial pace of about 40 ft. per day. "We saw the glacier advance like it never had before," says Branham. That was in April. Within weeks, the leading edge of ice had sealed off the fjord at its opening, turning the 32-mile-long inlet into a fast-rising lake and trapping porpoises, harbor seals and the saltwater fish and crabs they live on.

Alarmed, most of the 500 residents of the nearby fishing village of Yakutat gathered in the Alaska Native Brotherhood Hall for a briefing by scientists who have flocked to study what the U.S. Geological Survey has called a "world-class natural event." By last week, waters of the stream-fed fjord, renamed Russell Lake, had risen more than 62 ft., and were still climbing, covering the beaches and then the steep, alder-lined banks.

The immediate danger, explained USGS Glaciologist Larry Mayo, is that the lake, now rising about 1 ft. a day, will spill out of its southern end into the Situk River (see chart), a salmon-spawning stream that is the economic lifeblood of Yakutat. If the lake overflows, the clear Situk could become a destructive torrent of silty water about 20 times its present volume, unfit for salmon and fishermen. "In another 500 to 1,000 years," says Mayo, "Hubbard Glacier could fill Yakutat Bay, as it did in about 1130." Susie Abraham, 85, a silver-haired elder of Yakutat's native Tlingit Indian tribe, is fatalistic. "This place where we sit," she says, "belongs to the great glacier."

The animals trapped in Russell Lake are almost certainly doomed. Freshwater from the mountain streams sits atop the denser salt water, with little mixing. As a result, oxygen, which is replenished at the surface through diffusion, cannot be replaced once it is depleted from the salt water. Fish and crabs might last for a year, but the air-breathing sea mammals that eat them will not. "The seals are exhausted from diving through that extra 50 ft. of freshwater before they can reach salt water and maybe find something to eat," says Marine Biologist Tamra Faris of the National Marine Fisheries Service. On her last flight over the lake in mid-July, Faris counted seven harbor porpoises and three Dall's porpoises; last week the porpoises could be seen cruising back and forth along the glacial dam, searching in vain for a passage back to the sea.

A glacier is a river of ice fed by mountaintop snowfall. When the ice becomes thick and heavy enough, it starts to flow like an extremely viscous fluid, its uphill section always advancing, its end, or terminus, moving forward or back, depending on factors like how fast the terminus melts or breaks off into the sea. Although glaciologists can describe a glacier's movements and predict its effects, they cannot explain why the Hubbard Glacier or any of the 15 or so smaller frozen masses that are also surging in the Yakutat area -- albeit harmlessly -- began to speed up, while others nearby have slowed. Some factors scientists think cause glaciers to advance and retreat: the amount of snowfall at high altitudes and changes in global temperature and in the local climatic conditions at each glacier.

Many specialists believe each glacier has a distinct personality and rhythm. Says Will Harrison at the University of Alaska: "Glaciers are delicate and individual things, like humans. Instability is built into them." Harrison and other experts emphasize the influence of what they call the "plumbing" -- the movement, retention and loss of liquid water within and under the ice that acts as a lubricant.

While the surging glacier may bring disaster to Yakutat, it provides a rare opportunity for scientists to study a major geophysical event. Mayo sympathizes with the villagers yet can scarcely contain his excitement. "This is probably the largest natural alteration in oceans, glaciers, lakes and rivers to occur in our lifetimes," he says, and it offers "unprecedented opportunities" for research. The villagers do not share his enthusiasm. Says Yakutat Grocer and Planning Official Caroline Powell: "We are people, not some scientist's experiment or opportunity. Everyone seems content to watch this happen, and if they feel sympathy, it's for the porpoises and seals. What about us?"

Her husband, Yakutat Mayor Larry Powell, agrees. While it is possible that the ice dam will give way under mounting water pressure behind it, there is no guarantee. He suggests that a channel be dug from the lake to the sea, bypassing the Situk so that the trapped water can escape without affecting the river. Others propose bombing the glacier: controlled explosions could blast a trench through the ice itself. But speed may be essential. Says Powell: "We're just now entering the rainy season, and at the rate it's filling, the lake could be ready to make its jump by the end of this year." Experts say, however, it will take a year or two. The Tlingit elders are contemplating another solution, one they say worked for their ancestors the last time that ice covered Yakutat Bay, nearly nine centuries ago: sacrificing a dog at the glacier's leading edge.

With reporting by Dan Goodgame/Yakutat