PORTLAND, Ore. - The U.S. Geological Survey says three glaciers in Alaska and Washington continue to shrink, a development that signals lower stream flows in summer months.
A report by a researcher at the USGS Water Science Center in Tacoma, Wash., Edward Josberger, finds a rapid and sustained retreat of the Wolverine Glacier on Alaska's Kenai Peninsula and the Gulkana Glacier in Interior Alaska, as well as the South Cascade Glacier in Washington state, which is in the North Cascades near Sentinel Peak.
Scientists have been studying the three glaciers for 50 years and say the rate of retreat has increased in recent years. They use their findings as benchmarks to determine what's happening to other glaciers.
"As these glaciers shrink, they have an important impact on late-summer stream flows," Josberger said. "At the end of summer, especially this summer, glaciers are the only show in town for fresh water."
Melting glaciers provide a small percentage of the domestic water supply in the Pacific Northwest, so the findings don't mean a water shortage, Josberger said. But streams in the North Cascades are home to endangered fish species such as bull trout and chinook salmon that depend on "cold, highly oxygenated water" at the end of summer, he said.
Seattle City Light is concerned that reduced stream flows impact electricity production at its dams, Josberger said.
The change will result in glaciers of the North Cascades looking more like their counterparts in Oregon's mountains: smaller and contained at higher altitudes, he said.