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Tracking glaciers the Tangborn way

Vashon glacier expert Wendell Tangborn uses data from weather stations to measure the size of glaciers. His methods are unorthodox and his findings are disturbing - if you like ice.
Glacier expert Wendell Tangborn

Glacier expert Wendell Tangborn Andrea Lewis

View of Raven Glacier from Crow Pass in Alaska

View of Raven Glacier from Crow Pass in Alaska Photo: Frank Kovalchek

Wendell Tangborn thinks he has invented a better mousetrap. He's still waiting for the scientific world to beat a path to his door.

Sitting in a cramped home office overlooking the (rising) waters of Puget Sound, Tangborn talks about his plan to monitor 200 glaciers around the world to see whether or not — and, if so, how quickly — they're melting away. He has already done detailed reports on seven, including Juneau's incredible shrinking Mendenhall Glacier. He's working on 40 more, and hoping one or more foundations will supply enough money to hire the three people he'd need to keep track of all 200.

People often cite the waxing or waning of glaciers to prove that the earth is or is not getting warmer. But according to Tangborn, no one is looking systematically at a large number of glaciers so that trends become obvious and the glaciers which are behaving contrary to the trends can be seen clearly as outliers.

Basically, he uses temperature and precipitation data from fixed weather stations to calculate a glacier's "mass balance" — that is, the difference between the winter accumulation of snow and the summer melting of snow and ice. A positive balance means the glacier is growing; negative means it's shrinking.

The program must be customized for every glacier. Tangborn must take account of the topography and total area of the glacier's surface. Once he plugs that into the program, he can sit in his office and get information that's as reliable as the data produced the old-fashioned way — the way he did it for many years — by climbing around on the ice with probing rods and shovels.

For each glacier, Tangborn has to find a weather station that produces results in line with actual observations. That isn't necessarily the weather station right next door to the ice. Austrian scientists can't believe that Tangborn's using a weather station in Innsbruck to monitor the Vernagtferner glacier, which is 100 kilometers away, rather than a station close to the site. But, says Tangborn, somehow local weather phenomena keep the closer station from producing useful numbers.

Tangborn's monitoring program runs on old PCs in that office of his on the west side of Vashon Island. Big photographs of Alaska's Columbia Glacier adorn one wall. Tangborn studied that glacier in the 1990s with the late Austin Post. (Icebergs calved from the Columbia Glacier forced the tanker Exxon Valdez out of the normal sea lanes that night in 1989 when it ran aground and spilled 11 million gallons of crude oil into Prince William Sound.) The litter of publications includes a children's book on glaciers written by Tangborn himself.

Tangborn saw his first glacier in 1960, when the U.S. Geological Survey transferred him from his native Midwest to Washington and sent him out to the North Cascades to help study the South Glacier. That's the glacier just outside North Cascades National Park, whose meltwater feeds the south fork of the Cascade River. (The work was done for the Water Resources Division of the US Geological Survey, which had started it three years earlier, in part, to gauge the effects of climate change. The division's chief hydrologist at the time was Luna Leopold.)

Six years ago, Tangborn wrote about his first-year experience at the glacier for The Wild Cascades, published by the North Cascades Conservation Council. "It was a typical day at South Cascade Glacier in October," he wrote, "wet, cold, windy, cloudy and dark. After breakfast we gathered up the equipment we would need for the day (ice axes, current meter, measuring tapes, snow probing rods, rubber hip boots, collapsible wading rod), packed a lunch (a can of sardines, a box of Ry-Krisp and a can of apple sauce), dressed in the most water-proof clothes we could find and headed up glacier. The rain turned to snow as we gained elevation ... One of the vital goals of the project was to measure the glacier’s balance and determine if it was gaining or losing mass. Visibility was now down to 10 or 15 feet ... One measurement was a little frightening as it was just above [a round shaft], into which the glacier stream poured, making a thunderous roar as the water fell 200 feet to the glacier bed."


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Comments:

Posted Tue, Mar 19, 9:45 p.m. Inappropriate

Fascinating stuff. A number of researchers are tracking the decline of our glaciers, including a team led by Dr. Mauri Pelto out of the U.W. I believe. Their efforts are also chronicled in issues of "The Wild Cascades" journal mentioned in this article. Issues can be seen on the North Cascades Conservation Council website.

Our local glaciers have come and gone before, and I think that some researchers believe that they pretty much disappeared during the "hypsithermal" period 5000 or so years ago. Seattle was then probably mostly oak savannah, perhaps similar to what some of the drier parts of the San Juan islands and other such places look like today.

But that was part of the natural ebb and flow, and not caused by skyrocketing levels of CO2. The current disappearance is scary, and makes one wonder if maybe those who theorize that humans are here to simply unlock carbon and go extinct aren't on to something.

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