Glacier-Formed Dam Springs Major Leak

A dam formed by the advancing Hubbard Glacier in southeastern Alaska has sprung a giant leak, releasing a torrent of water and ice from 70-square-mile Russell Lake, scientists said Thursday.

Glaciologist Dennis Trabant, who was in Yakutat with a state emergency services team, estimated the flow into the sea at about 300,000 cubic feet per second, equal to at least three-fourths the flow of the Yukon River.

“The water is absolutely cascading out,” Trabant said. “It’s one heck of a lot of water.”

Trabant said he and others hovered in a helicopter near the top of the 300-foot-tall glacier at midday, looking down on the area where the Hubbard had pushed a gravelly moraine hard against Gilbert Point more than three weeks ago, creating Russell Lake.

Instead of moraine, however, they saw a raging river roughly 300 feet wide and 600 to 700 feet long.

“It’s absolutely roiling and boiling, chaotic,” he said.

The lake’s level had risen steadily since the glacier and its moraine started pinching off the entrance to Russell Fiord in late June. The rate increased when the moraine sealed off the fiord, and it spurted in the last week as heavy rains fell.

The lake rose more than 3 feet Tuesday, cresting at about 61 feet above sea level. But then the lake began overflowing the moraine, eroding it, until it let go Wednesday night.

Scientists say the Hubbard is on a slow advance and eventually will close off the mouth of Russell Fiord.

That would cause the newly formed lake, fed by snowmelt and rainfall, to rise in the mountainous basin around the fiord until it overflows into the Situk River, wrecking prized steelhead and salmon sport and commercial fisheries that are the backbone of the Yakutat economy.

The threat of that happening prompted Yakutat city and borough officials to ask Gov. Tony Knowles to help them begin planning for an economic disaster. Knowles responded by sending in a team headed by Maj. Gen. Phil Oates, Alaska’s adjutant general, to evaluate the situation.