'Experts' worry about flooding, not enough water for salmon due to 'possible global warming'
Scientists say weather fluctuations, global warming and human activity are causing some glaciers to shrink and are affecting snowpacks -- the snowdrifts that melt each spring before they can compress and turn into glaciers.
Lessened spring runoff means less water in the rivers that produce hydroelectric power, irrigation and drinking water and sustain the region's salmon runs.
If the trend continues, some experts think the region may have to considering building more dams, or choose between using river water for power or leaving it for salmon.
Scientists estimate that South Cascade Glacier, 25 miles east of Darrington, has shrunk 40 percent since the last severely cold period 350 years ago. The end of the glacier has retreated nearly two-thirds of a mile since 1928, said Ed Josberger, who heads a glacier-monitoring team for the U.S. Geological Survey in Tacoma. A lake has formed where the toe of the glacier once reached.
The shrinkage occurred even though the region has experienced several lengthy spells of cold weather that might have helped the glaciers grow.
The National Park Service has begun measuring the effects on glaciers in North Cascades National Park.
North Klawatti and Noisy glaciers, in the North Cascades, have each lost three feet or more in their vertical mass since 1993. In each case, the loss is considered significant; the loss at Klawatti is equivalent to more than 10,000 Olympic-size swimming pools. Seasonal water runoff from Klawatti Glacier supplies Diablo Lake, where the water is used to generate hydroelectric power.
A study of Mount Rainier glaciers shows that most major glaciers except Nisqually Glacier became smaller during an 80-year period.
Similar changes have been noticed in glaciers in Alaska, Montana, Canada and in the Andes range in South America.
Philip Mote and others on a University of Washington team of climate experts say global warming is a likely cause, though they differ on how much of the warming is due to human activities such as fuel burning.
Others, like UW hydrologist Alan Hamlet, say changing weather patterns could explain why many glaciers and snowpacks are shrinking. The region has experienced four different phases of alternating warm-and-dry and cool-and-wet weather since the mid-1920s.
And two of the North Cascades glaciers being monitored, Silver Glacier and Sandalee, have grown in the past decade because the mountain peaks shade them more than others.
Seattle, which has 1.3 million water customers, has asked the UW team to study the possible effects of global warming on its system. Faster melting of snow may force the release of more water from reservoirs and cause possible downstream flooding.
Lower summer flows could mean too little water in the rivers for fish, while water demand could rise because of higher temperatures.
Earlier melting would send more water through hydroelectric dams, producing more power in winter when the Northwest needs it. But lower summer flows would mean less power production when the Northwest typically sells power to the Southwest, said Northwest Power Planning Council analyst John Fazio. That lost revenue could prompt rate increases.
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