IDAHO RESERVOIRS LIKELY TO FILL

Published online: Jan 31, 2011 Irrigation
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BURLEY, Idaho-The water year that began Oct. 1 has gotten off to a great start, and the trend is likely to continue through the winter, experts told farmers attending the Idaho Irrigation Equipment Show and Conference.

A year ago, Idaho snowpack was near record lows in some part of the state, but there's been a remarkable turnaround. This year, snowpack levels are running well above average, especially in the southern half of the state, experts said.

On Jan. 18 snowpack levels in the Upper Snake River region were about 20 percent above normal and about 45 percent above average in the Bear River Basin, according to U.S. Natural Resources Conservation Service snow survey data.

"The first quarter of the water year has gone pretty well," Troy Lindquist, service hydrologist with the National Weather Service office in Pocatello, Idaho, told producers Jan. 14.

A La Niña weather pattern, which typically brings above-average precipitation and below-average temperatures to the Northwest, is still in play, Lindquist said.

The long-range forecast calls for an increased probability of above-average precipitation through March.
 
"Is La Niña going to continue? We think it's going to continue at least into the spring of this year," Lindquist said.

Long-range forecasts show an increased probability for below-average precipitation from April through July.

If that forecast plays out, it would be a significant departure from what has occurred in Idaho the past two years.
 
Heavy spring rains were a godsend in 2010, helping to fill reservoirs in a year with reduced snowpack accumulation.

"We saw the potential for some flooding in a year with 60 percent snowpack," said Michael Beus, hydrologist with the U.S. Bureau of Reclamation office in Burley.

Reservoirs in the Upper Snake River system are almost certain to fill this year, and the bureau is planning to make some releases soon to manage for flood control, Beus said.