Mt. Logan's Memory of the Last 10,000 Years
In early June 2001, six mountaineers were stuck in bad weather near the summit of Canada’s highest mountain. To pass the time, they swapped stories, read paperbacks, and preserved their strength for the task ahead. Stuck at 17,000 feet, these climbers were not waiting for a push to the summit; they were awaiting the arrival of a drill that would allow them to sample snow that had fallen more than 10,000 years ago.
The climbers, three of them scientists, were part of an expedition to recover the ancient ice held by Mount Logan, a 19,551-foot peak in the St. Elias range, in the Yukon Territory just east of the Alaska border. If weather permits helicopter travel within the next week, researchers from Canada and the U.S. will extract a 600-foot core of ice from the mountain. Pollen, volcanic ash, sea salt, and other remnants from prehistoric atmospheres are trapped within the snow beneath the scientists’ tents, at a level on Mount Logan where the average temperature is 20 below zero Fahrenheit.
David Fisher is a glaciologist for the Geological Survey of Canada who is coordinating the project from a much warmer place, Kluane Lake Research Station in the Yukon. As the climbers, among them Fisher’s colleague Mike Demuth, waited on the mountain, Fisher watched the weather reports and prepared to call for a helicopter to ferry the drill from a lower camp as soon as the sky cleared. With clouds and high winds stalling the operation, he had time to explain over the phone why scientists want to take a core from one of the tallest mountains on the planet.
“Mount Logan is one of the best places in the western Arctic to find old ice that’s lying flat,” Fisher said.
Researchers have drilled ice cores all over the Arctic, including on the ice cap of Greenland, but they do not yet have a good record of what was occurring thousands of years ago near the western Pacific Ocean, Fisher said. Besides being a melt-free storage area for snow, Mount Logan also features a somewhat flat area 2,000 feet beneath the summit. There, where the mountaineers are camped, is a suitable spot to set up a drill without worrying about equipment or people tumbling from a steep slope.
Assuming the weather clears, the drill works, and the ice core survives the trip to Ottawa, the sample tubes of Mount Logan ice will tell researchers about snow over southwestern Yukon during the thousands of years past. Fisher expects to find salt from the ocean, ash from volcanoes, pollen from trees and plants that have long since been extinct, and possibly bacteria and viruses. The snow layers also will provide evidence of ancient temperature swings and snow accumulation.
Mount Logan already has proven itself a good preserver of airborne hitchhikers within Earth’s atmosphere—researchers at lower camps noticed a dark layer that stained the snow in April 2001. Fisher thinks the dirty snow may be dust from a storm in the Gobi desert that traveled around the globe recently.
The mountaineer-scientists on Mount Logan, who climbed the mountain to acclimatize rather than taking a helicopter ride, have enough supplies to last two more weeks. The weather may clear any day now to allow the helicopter to take off from Haines Junction and ferry the 600-pound drill to the high plateau on Mount Logan. Or, as is often the case in the mountains, the climbers will finish all their books, tell all their stories, and hope for better weather next year.
