Fall 2002 - The North Cascades

Fall 2002 - The North Cascades

Barometer
by Colin McDonald

South Cascade Glacier, 1928.
Photo Courtesy USGS, Washington Water Science Center

The last thing Dylan Taylor remembers is the ice disappearing beneath his feet.

"I just free fell," Taylor said. "I thought I was going to die."

Taylor was leading a three-person rope team down the Coleman glacier on Mount Baker in late September of 2000 when one of his clients broke through a snow bridge, pulling Taylor and his other client into a crevasse.

Snow bridges form every winter as snow covers the openings of crevasses, deep cracks in a glacier, and climbers use them to negotiate across the cracks. On this particular afternoon, sun had weakened the 8-foot-long bridge causing it to collapse, dropping Taylor and his clients into the depths of the glacier.

"I could feel the tension in the rope increase when the second guy went over," Taylor said. "I had this sense of panic as I realized I was not slowing down. I don't remember anything after going over the edge."

When Taylor regained consciousness, he was lying next to his clients and bleeding from his head - 45 feet below the surface of the glacier. They were lucky, a jumble of ice blocks wedged between the walls of the crevasse saved Taylor and his clients from plummeting another 100 feet to the bottom.

South Cascade Glacier, 1979.
Photo Courtesy USGS, Washington Water Science Center

The glaciers of the North Cascades are constantly changing. Taylor witnessed one of these changes first hand and it almost killed him. But the collapse of a snowbridge is only a small part of much larger changes happening to the glaciers of the North Cascades. Researchers now use the glaciers as barometers, measuring glacial retreat and snow accumulation to understand small changes in the climate and atmospheric pollution levels.

North Cascades National Park geomorphologist Jon Riedel studies the glaciers and landscape of the North Cascades. In 1992, Riedel received funding to start monitoring the glaciers in the region.

"We knew that the climate was changing and that the glaciers were an excellent indicator of that," Riedel said. "We knew that if we could start monitoring these glaciers it would be an indicator of change for the whole ecosystem, terrestrial as well as aquatic."

Every year, Riedel and two research scientists from the Park Service measure snow levels on the Noisy, Silver, Sandalee and North Klawatti - four glaciers in the park. By comparing winter ice accumulation with summer melting, Riedel and his team are able to determine if the glaciers are growing or shrinking.

Riedel's monitoring allowed him to construct a chart of changes in the glaciers for the past 150 years. Comparing his data and U.S. Geological Survey graphs with climate indicators such as tree rings, Riedel said he correlated patterns of growth in trees with longer periods of retreat by glaciers.

In the winter of 1999, the Mt. Baker Ski Area in the North Cascades set a world record for snow accumulation with 95 feet of snow. At the end of the summer, snow remained on the glaciers, making 1999 a positive balance year and the beginning of a short glacial growth period.

South Cascade Glacier, 2000.
Photo Courtesy USGS, Washington Water Science Center

In the past 150 years North Cascade glaciers lost 44 percent of their cover because of warmer summers and less snowfall, a trend even large snow years like 1999 can't compensate for.

"At these rates of change, I could believe that sometime in the next half of this century we would lose our glacier cover," Riedel said.

With the capacity to store ice for decades, alpine glaciers act as high mountain reservoirs - storing winter snows for summer melting and balancing out the wet and dry seasons. This ability to equalize stream flow is reduced as the glaciers shrink.

While this melt water replenishes mountain lakes and feeds tributaries, it also carries pollutants. Distilled out of the air by cold temperatures or precipitated out of the atmosphere in snow and rain, the pollutants collect on the glaciers.

High mountain lakes from the Sierra Nevadas to the Canadian Rockies contain pollution, with contaminants such as DDT and mercury showing up in fish, otters and eagles.

"It all comes back," Riedel said. "You can't just dump pollution on that side of the ocean or up the river. It's going to come right back down on you."

Patrick Moran is a USGS biologist researching toxic compounds in high-mountain-lake fish.

"Some studies have shown that the North Cascades might be a trap for certain air pollutants," he said. "Similar studies, done in the Canadian Rockies and the Sierra Nevadas, show that there is an increase in organochlorines as you increase elevation."

To measure pollution levels, Moran and other USGS biologists studied fish from 14 mountain lakes in North Cascades National Park, Rainer National Park and Olympic National Park. The lakes range from 3,500 feet to 6,600 feet and are considered pristine by the park. With no other considerable inputs, the only source of pollution to the lakes is from the atmosphere. Moran intends to find out to what extent these lakes are polluted.

"We're using the fish as a canary in the coal mine," Moran said. "If there are problems they will show up in the fish."

Moran will have the results of the tests this winter. If the fish test positive for organochlorines or mercury, the lakes will undergo further testing.

Ideally, Moran will find few pollutants in the fish, but with current local and historic pollution, and increasing global pollution, he said that is unlikely.

For the past five years, University of Washington professor Dan Jaffe has studied pollution levels in air masses crossing the Pacific Ocean. The industrialization of South Asia, along with massive forest fires and expanded use of arid farming, led to radical increases in air pollution levels over the past 30 years, Jaffe said.

"It is difficult to put a number on it, but I would say that 10 to 15 percent of our air pollution comes from South Asia," Jaffe said.

Powered by the jet stream, the westerly winds pick up dust from the Gobi desert, DDT and PCBs from the arid farmland of southern China and mercury and other heavy metals from coal-fired power plants. With satellite imagery, Jaffe watches the dust cloud cross the Pacific Ocean and takes air samples when the mass arrives over Washington.

"The particulates either smack into the mountains, are dropped out or pass right over," Jaffe said. "If it does not hit us, they have to deal with it in Utah."

He said air pollution sources are difficult to pinpoint. While the pollution in glaciers can come from as far away as Europe, the majority comes from local sources, Jaffe said.

"The thought is that it may be a bigger problem here (in the North Cascades) because we get so much snow," Riedel said.

The glaciers of the North Cascades are a changing resource. They keep streams and dams flowing, provide recreation and serve as a benchmark for environmental change.

When fellow guides pulled Taylor from the crevasse, he did not know if he would ever guide again. But, he returned the next summer to share the mountains with others. Taylor is now more aware of his surroundings and shares his story with his clients so they can better understand what forces are acting on the glacier.

Moran and Riedel do not have an explanation for what is happening to the glaciers of the North Cascades. While the human role in the changes is not clear, we are far from being free from responsibility.

"It is a little disconcerting that we leave the public with the notion that this is not our problem," Moran said. "It definitely is."

Junior Colin McDonald studies environmental journalism at Huxley College. He has previously been published in The Western Front, The Whatcom Watch and The Planet.

Fall 2002 - The North Cascades

Barometer by Colin McDonald

Barometer
by Colin McDonald