GLOBAL WARMING FORECAST TO MELT PACIFIC NORTHWEST SNOWPACK
ENS March 13, 2006
http://www.ens-newswire.com/ens/mar2006/2006-03-13-09.asp
CORVALLIS, Oregon - Global warming in coming decades may cause the disappearance of large areas of the low-elevation snowpack in the Cascade Range of the Pacific Northwest, a new study concludes. Area ski resorts will face warm winters far more often than they do now, predict the authors, geographers from Oregon State University (OSU).
The new OSU study, based on computer models, details the "at risk" snowpacks in the Pacific Northwest. Most lie in Oregon's Cascade Range, parts of the southern Cascade Range of Washington, and Olympic National Park.
Similar impacts are also possible for portions of the southern Cascade Range in Washington, and also in Washington's Olympic Range, most of which is in Olympic National Park. There, global warming is projected to melt 61 percent of the snow cover.
"Previous studies show that snowpack has fluctuated widely in the past, but appears to be trending downward in the Pacific Northwest since the 1920s," said Anne Nolin, an assistant professor in the OSU Department of Geosciences.
"This region has already experienced the largest declines in snowpack in the western United States. What we're able to do now is identify much more precisely where the snow may disappear, based on the warming we expect," Nolin said. "We've never before had projections that are this specific in their spatial scale."
For their study, Nolin and Chris Daly, an associate professor of geosciences, used widely accepted global climate models which, on average, suggest this region may warm about 3.5 degrees Fahrenheit in the next 40 years.
While than two percent of the current snow-covered area is modeled to be at risk in the future in a four state Pacific Northwest region that includes Idaho and parts of western Montana, more than half of all the "at risk" snow is in the Oregon Cascades.
Nolin team projects that about 22 percent of the area in the Oregon Cascades could soon experience precipitation that falls as rain in the winter, rather than as snow.
Some of the most profound impacts may be on ski resorts in the region, the scientists said, especially those at the lower elevations.
For instance, based on the increase in temperature that is expected 40 years from now, the study showed that Mt. Hood Meadows, a popular ski area near Portland, Oregon, may experience warm winters about seven times more frequently than it does now - going from a warm winter seven percent of the time to 47 percent of the time.
A warm winter means that, based on the elevation of the ski area, climate conditions, and other local geographical conditions, precipitation that now falls predominately as snow during December, January and February will instead fall predominately as rain.
The potential for changes in snow and rain precipitation patterns, the researchers say, could affect not just ski resorts but also stream flows, fisheries, flood control, hydroelectric power generation, irrigated agriculture and other water-related activities.
Reductions in summer stream flow as a result of diminished snowpack would be a special problem for fisheries management, the researchers said.
Similar concerns would almost certainly affect the Sierra Nevada range of California, the researchers said, but an analysis of that region was not a part of this study.
The report has been accepted for publication in a future issue of the "Journal of Hydrometeorology," a publication of the American Meteorological Society. The work was funded in part by the U.S. Geological Survey and by NASA.
Informant: NHNE
http://www.ens-newswire.com/ens/mar2006/2006-03-13-09.asp
CORVALLIS, Oregon - Global warming in coming decades may cause the disappearance of large areas of the low-elevation snowpack in the Cascade Range of the Pacific Northwest, a new study concludes. Area ski resorts will face warm winters far more often than they do now, predict the authors, geographers from Oregon State University (OSU).
The new OSU study, based on computer models, details the "at risk" snowpacks in the Pacific Northwest. Most lie in Oregon's Cascade Range, parts of the southern Cascade Range of Washington, and Olympic National Park.
Similar impacts are also possible for portions of the southern Cascade Range in Washington, and also in Washington's Olympic Range, most of which is in Olympic National Park. There, global warming is projected to melt 61 percent of the snow cover.
"Previous studies show that snowpack has fluctuated widely in the past, but appears to be trending downward in the Pacific Northwest since the 1920s," said Anne Nolin, an assistant professor in the OSU Department of Geosciences.
"This region has already experienced the largest declines in snowpack in the western United States. What we're able to do now is identify much more precisely where the snow may disappear, based on the warming we expect," Nolin said. "We've never before had projections that are this specific in their spatial scale."
For their study, Nolin and Chris Daly, an associate professor of geosciences, used widely accepted global climate models which, on average, suggest this region may warm about 3.5 degrees Fahrenheit in the next 40 years.
While than two percent of the current snow-covered area is modeled to be at risk in the future in a four state Pacific Northwest region that includes Idaho and parts of western Montana, more than half of all the "at risk" snow is in the Oregon Cascades.
Nolin team projects that about 22 percent of the area in the Oregon Cascades could soon experience precipitation that falls as rain in the winter, rather than as snow.
Some of the most profound impacts may be on ski resorts in the region, the scientists said, especially those at the lower elevations.
For instance, based on the increase in temperature that is expected 40 years from now, the study showed that Mt. Hood Meadows, a popular ski area near Portland, Oregon, may experience warm winters about seven times more frequently than it does now - going from a warm winter seven percent of the time to 47 percent of the time.
A warm winter means that, based on the elevation of the ski area, climate conditions, and other local geographical conditions, precipitation that now falls predominately as snow during December, January and February will instead fall predominately as rain.
The potential for changes in snow and rain precipitation patterns, the researchers say, could affect not just ski resorts but also stream flows, fisheries, flood control, hydroelectric power generation, irrigated agriculture and other water-related activities.
Reductions in summer stream flow as a result of diminished snowpack would be a special problem for fisheries management, the researchers said.
Similar concerns would almost certainly affect the Sierra Nevada range of California, the researchers said, but an analysis of that region was not a part of this study.
The report has been accepted for publication in a future issue of the "Journal of Hydrometeorology," a publication of the American Meteorological Society. The work was funded in part by the U.S. Geological Survey and by NASA.
Informant: NHNE
rudkla - 15. Mär, 16:38
