July's record-high temperatures contribute to long-term glacial wasting
By RICHARD HANNERS
Whitefish Pilot
July's record heat wave didn't just melt the ice cubes in your cocktail glass. It continued the melting process that sent a torrent of water down Glacier National Park's mountains during June, leaving much of Park's alpine slopes high and dry.
According to official temperatures from Glacier Park International Airport, July 2007 was the hottest month since record-keeping began more than 100 years ago. The 92-degree average daily high temperature was 11.8 degrees above normal.
It's not just snowfields that melted away. Blame it on global warming or Mother Nature, but it's just not news anymore — the Park's glaciers are dramatically shrinking.
They've even the become the target of black humor — witness a recent contest to rename the Park put on by The National Environmental Trust.
That doesn't deter scientists like Dan Fagre, an ecologist and climate-change research coordinator at the U.S. Geological Service's Northern Rocky Mountain Science Center, based at the Park's headquarters near West Glacier.
Fagre says the Park's namesake glaciers are predicted to disappear by 2030, primarily because of long-term changes in regional and global climate.
"In the past decade, Glacier National Park has experienced dramatic climate variability that includes record winter and summer droughts, near record summertime temperatures, as well as near-record winter snowfall," he says in his Web site.
"While the Park's glaciers continue to shrink, it is not clear whether these dramatic fluctuations have accelerated or slowed glacier recession and downwasting," he says.
Thus the need for study. Fagre says few measurements of glacial volume or mass have been made.
"Measurements of area alone can be misleading," he said.
The U.S. Geological Service's study uses Sperry Glacier as the benchmark glacier. It was first studied by Lyman Sperry in 1886, long before the Park was established in 1910.
Six secondary glaciers were also chosen for study, including one that is outside the Park, the Stanton Glacier on the north side of Great Northern Mountain, and the Jackson-Blackfoot Glacier, which long separated into two glaciers and is visible from the Going-to-the-Sun Road.
"Data about the benchmark glacier is typically collected annually, with the secondary glaciers studied less frequently or with remote sensing," Fagre said.
To study the mass of water a glacier gains or loses each year, the height of the glacier is measured in late spring and late summer. The first measurement determines how much snow fell over the winter; the second shows how much was lost by melting.
Area measurements are made with high-precision global-positioning system receivers in the field. In the case of the Grinnell Glacier, that can mean paddling around the edge of the melting glacier in the lake that has formed there.
Another technique used by the scientists is repeat photography — before and after shots of the Park's glaciers. A collection of historic photos has been started, and photos are repeated on five-year intervals. Remote sensing from satellites and hydrology studies of runoff water are other study tools.
A show on Fagre's work will be shown on Montana PBS as part of the "Montana Focus" series on Sept. 20, 22 and 23. See local listings for times.