A VOLCANIC eruption that sent a huge ash plume into the Alaskan sky threatened to strand 130 climbers on Mount McKinley, North America's tallest peak, officials said Sunday.
The climbers had expected to be ferried by ski plane off McKinley's 7,200-foot Kahiltna Glacier base camp. But Saturday's eruption of Mount Spurr showered ash on the snow runway at Kahiltna, the starting and ending point for most expeditions.
The ash plume from the volcano, 80 miles west of Anchorage and 130 miles south of McKinley, is blocking the sun, hastening the runway's summer meltdown.
And it is making future glacier landings and takeoffs dangerous, National Park Service spokesman John Quinley said.
Veteran glacier pilot Jim Okonek said air-taxi companies based in Talkeetna, the town closest to the mountain, had planed to close the Kahiltna base camp Monday.
The ash has made future fixed-wing landings unsafe, he said.
Climbers bent on assaulting McKinley continued to arrive in Talkeetna after Mount Spurr's eruption.
But the pilots have ceased flying any onto the mountain who expect a return flight from Kahiltna Glacier, Mr. Okonek said.
"No one's flying anybody in anymore unless they're prepared and with the full intent of walking off the mountain," he said.
The makeshift Kahiltna runway remained in serviceable shape Sunday, thanks in part to climbers who spent much of Saturday smoothing it with their climbing boots and snowshoes, Quinley said.
Some 50 climbers were expected to be picked up from Kahlitna Glacier Sunday, leaving about 130 on the mountain, Quinley said.
Climbers usually ascend McKinley between late April and mid-July, the period when Talkeetna-based glacier pilots can land their planes on the lower flanks of the 20,320-foot peak.
Descending the mountain's glaciers into the wooded, trailless wilderness surrounding McKinley's lower reaches can be a grueling route, Quinley said.