FAIRBANKS, Alaska (AP) _ Scientists know they can't stop a rapidly expanding glacier that threatens a world-class salmon stream and has turned a fiord into a lake, but they hope to get ready for it.

Officials from the U.S. Forest Service, the National Park Service, Sealaska Corp., the Alaska Department of Fish & Game, the U.S. Geological Survey and the National Weather Service met Thursday at the University of Alaska- Fairbanks to begin planning.

''We're not going to stop the glacier, but there may be some things we can prepare for,'' said Jere Christner of the U.S. Forest Service in Sitka.

The errant Hubbard Glacier began an unprecedented surge along with others in the same area of southeast Alaska earlier this year, said Larry Mayo, a Fairbanks-based glaciologist with the U.S. Geological Survey.

In the past two months it has surged into Disenchantment Bay on Gilbert Point north of the town of Yakutat, about 300 miles southeast of Anchorage.

On June 1, the glacier ran into a hill on the south side of the bay, cutting off 25-mile-long Russell Fiord and turning it into Russell Lake, officials said. The lake water has risen more than 20 feet since then and is drowning trees on the shore.

If the water rises more than 200 feet, it will crest the lake's southern end in two years and wash a channel through the Situk River, probably destroying the small but world-class salmon stream, scientists said.

Mayo said no one knows exactly why the glacier is moving. It might be caused by a spurt of seismic activity in the region or extra-heavy snowfalls.

Cyril Wanamaker, minerals manager for Sealaska Corp., said an overflow from Russell Lake could destroy the salmon run for hundreds of fishermen who depend on it for their livelihoods.

He said he also is worried about damage to homes, fish camps, roads and bridges and called for warnings about how to deal with the glacier.

A new river spawned by the glacier could threaten valuable spruce and hemlock forests, he said. Much of that land may one day be owned by Sealaska and Yakutat's village corporation, as part of the Alaska Native Claims Settlement Act, he said.

Mayo said markers on the ice of a tributary glacier showed it had moved more than 34 yards in one day when he measured the flow on June 12 and June 13. That's three to four times faster than the fastest Alaska glaciers, he said.

Mayo said he also walked along the face of the glacier, where the ice was spitting up rocks and silt from the floor of the fiord. ''Not every rock was moving all the time, but the face was never quiet,'' he said.