Snow Scarcity Increases Chances
by Joe Rojas-Burke
A continued warming trend in the Northwest could create
severe problems in energy generation, farm irrigation and fish survival
Sunny winter days may be pleasant, but the persistent warmth and lack of snow is increasing the risk of another exceptionally dry summer that could drain irrigation reservoirs, kill fish and cut into electric generating capacity.
Across the Cascade Mountains from Oregon to Washington, many basins have gathered barely one-third the snow that is normal by this time of year. Even at elevations of 5,000 feet or more, warm temperatures are bringing rain and melting what little snow has landed.
"It's not a very pretty picture," said Jon Lea, snow survey hydrologist with the Natural Resources Conservation Service in Portland.
Lea and other officials say it's too early to know how dry a spring and summer we're in for. Much can change during the next two months, as recent experience has shown.
A year ago, the snowpack across much of Oregon had climbed above average, only to be whacked down by freakishly warm weather. In the rather dry winter of 2003, March deluges dumped almost twice the average monthly snow and rain into the Columbia Basin, turning a potentially severe water shortage into a not-so-bad year for river flows.
"We are probably headed for our sixth-straight year of below average water," said Nancy Stephan, manager of weather and streamflow forecasting for the Bonneville Power Administration, the federal agency that distributes electricity from the Columbia River hydropower system. "Our chances of reaching average right now are probably pretty tiny -- less than 5 percent."
Compared with snowpack, total rain and snow since October has been closer to average in the Northwest. But most of that moisture can't be stored in the many man-made reservoirs across the region. To protect downstream cities and towns from floods, the federal agencies have to keep those reservoirs empty enough to collect water during the big spring melt, when heavy rains trigger enormous surges in flow.
Geography has been helpful in the Columbia Basin. The big river and its tributaries stretch north well into Canada, where near-average snowfalls are piling up nicely. Runoff from melting snow and rain in the Canadian stretch of the Cascades delivers one-third of the Columbia River's flow, as measured at The Dalles Dam.
Taking that into account, the amount of water stored as snow basin-wide is holding at about 72 percent of average for this time of year, according to Bonneville's latest estimate. At this point in the drought year of 2001, the basin's snowpack was down to 52 percent of normal, and it was 40 percent of normal in 1977, another bad year.
Bonneville and private utilities say it's too early to say whether water shortages could drive up future electric bills.
Outside the Columbia Basin, water users are starting to worry. Snow in Southern Oregon's Klamath Basin on Thursday held 58 percent less moisture than in an average year. Water has not looked as scarce since the early 1990s, said Dave Sabo, who manages the federal Klamath Project.
Project farmers have faced water shortages before, especially when the government withheld water for protected fish in 2001. But the combination of a record dry year and the needs of fish could make this summer particularly parched.
"I'm not ready to start talking about shorting the project, but it's something they need to be thinking about," Sabo said.
This year's entrenched weather pattern is not raising much hope for a big comeback. Kelly Redmond, a climatologist with the Western Regional Climate Center in Reno, said the persistent pattern -- storms heading north and south of Oregon and Washington -- shows no signs of changing anytime soon. Another persistent feature is the temperature inversion: warm air riding atop a cold layer closer to Earth.
That's what's driving the oddly warm weather at high elevations. Temperatures this week in Bend and in Government Camp -- both at around 4,000 feet -- have been in the 60s, while temperatures in the Willamette Valley have stayed in the 50s, with fog.
Workers who perform routine maintenance on some of the more than 60 of Oregon's automated snow measuring sites have been forced to park their trucks at lower elevations on roads blocked by snow, and transfer to snowmobiles, only to find bare rocks and gravel above 5,000 feet.
A group that flew to a site near the west summit of Mount St. Helens this week, found only patches of snow. "There was not enough snow to sample," Lea said.
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