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Snowpack
Tue Aug 02, 2005
Listen in RealAudio 
Hi, I’m Bryan Yeaton for The Weather Notebook’s weekly Climate Change Series. Jeff Rice reports on a new study that shows snowpacks in the western U.S. are in steep decline.
The report, published in the “Bulletin of the American Meteorological Society”, is the first comprehensive look at changes in the west's snowpack levels. Snowpack refers to mountain snow accumulation.
What we found is that there were very strong downward trends in spring snowpack pretty much throughout the west.
Dr. Alan Hamlet is a climatologist with the University of Washington, and one of the authors of the report. Researchers analyzed snow data from the past 50 years and found declines of from 15 to 30% in the Rockies to more than 50% along some of the coastal ranges.
For example in the Cascade Mountains in Washington and in Oregon we see really dramatic downward trends in the last 50 years.
A major cause: increasing temperatures.
When you raise the temperature a little bit, you strongly effect where the snowline is. You raise the snowline up.
Hardest hit are the middle elevations where winter temperatures are already close to freezing, and where just a few degrees can mean the difference. Since 1947, temperatures in the west have been rising on average about .4 degrees Farenheit per decade, with an especially rapid spike in the last 30 years. Scientists say this is much faster than historically normal variation.
I think the conclusions of the study are basically that global warming has been happening for a long time and you see it clearly on the ground.
Climate models project a continued rise of 3 to 4 degrees over the next 50 years, and say continued dramatic decreases in snowpack levels could have serious consequences for the Western Water Cycle.
Jeff Rice reports from Boise, Idaho. The Weather Notebook is funded by Subaru of America. Help for our Climate Change Series comes from Environmental Defense.
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