Story published at magicvalley.com on Thursday, December 13, 2007 Last modified on Thursday, December 13, 2007 12:14 AM MST
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ASHLEY SMITH/Times-News Frost clings to grass along the Snake River Wednesday morning near Burley. Southern Idaho basins are on track for a below-average snow year and climatologists are changing earlier predictions for a wet winter.
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Poor start to winter
Snowpack levels below average, forecasters split on La Nina prediction
By Matt Christensen Times-News writer
Idaho's famous snowcapped mountains aren't quite as white as normal.
Despite early predictions for a wet winter and some recent snowstorms, snowpacks in southern Idaho are well below seasonal averages - bad news for farmers who rely on mountain snowpacks for irrigation water and electricity users who depend on spring runoff for low power rates.
"We're sort of below average across the whole state," said Phil Morrisey, a hydrologist for the Natural Resources Conservation Service, which measures mountain snowfall.
Packs are especially low in southern Idaho basins - just 68.8 percent of average. Snowpacks on this date last year, one of the driest years on record, were 70 percent of average.
Some forecasters, Morrisey said, have changed their predictions for a La Nina year, a weather pattern that typically brings above-average precipitation to the Northwest.
"We're kind of in a 'no' Nina," he said.
Forecasters at the National Weather Service in Boise, however, still predict a La Nina winter. Despite low early season snowpacks, precipitation is above normal, the agency points out. It's just fallen as rain.
"The La Nina is still going pretty strong in the tropical Pacific Ocean, so the official forecast is still indicating a La Nina," said Jay Breidenbach, a senior hydrologist with the NWS. "I would expect snow to improve later in the winter."
Farmers and power companies need Breidenbach to be right. If snowpacks aren't slightly above average, there might not be enough water come spring to keep the state from closing groundwater pumps, said Idaho Department of Water Resources Director Dave Tuthill earlier this year.
Energy rates also rise following poor snowpack winters. Idaho Power hiked rates by 20 percent in May following a below-average water year in 2006.
There is a silver lining to the snowless cloud: Early rainfall has saturated soils, meaning when the snow melts, it's more likely to raise stream flows.
A snowpack between 70 percent and 80 percent of average on Jan. 1 - almost halfway through the snowpack season - could make finishing the year at average within reach.
"It wouldn't be beyond reasonable possibility," Morrisey said.
Matt Christensen may be reached at 735-3243 or at matt.christensen@lee.net.
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