Idaho’s winter snowpack is looking good, but continued cold weather is needed to keep it in place and a few more snowstorms wouldn’t hurt, experts say.
“We don’t need spring to come too early like it did last year,” said Ron Abramovich of the National Resources Conservation Service. “It’s best if we can keep the snowpack in the high country longer and melt in May and early June and fill the reservoirs.”
Idaho’s snowpack ranges from about 150 percent of average in the south to 125 percent in the central portion of the state to 95 percent in northern Idaho.
Streamflow forecasts are for 90 to 120 percent of average for most of Idaho and should help irrigators and water storage. Streamflow predictions in southwest Idaho are from 135 to 150 percent of average for an area that hasn’t had an above average runoff since 2011.
“We’ve flown the watershed and there’s a pretty good blanket of snow out there,” said Clancy Flynn, manager of the South Board of Control that covers two irrigation districts, one in southwest Idaho and the other in southeast Oregon.
“But it’s not turned into water and it’s not sitting behind our big concrete wall that we divert the water from,” he said, referring to the Owyhee Dam on the Oregon side of the border.
He said a lack of water in recent years caused about 25 percent of cropland to not be planted last season in the two water districts, and land that was planted usually had less thirsty, though less lucrative, crops such as wheat and barley.
Like many workers involved in trying to figure out Idaho’s water outlook, being cautious has become part of the job following a string of difficult years.
“We’re off to a good start but we had the same thing happen last year and it didn’t turn out as well as we hoped,” said Sean Vincent of the Idaho Department of Water Resources.
Idaho in the early part of this winter benefited from storms coming in from the Pacific Ocean, said Troy Lindquist, a hydrologist with the National Weather Service in Boise. But that has since changed.
“Right now we’re in a very dry weather pattern,” he said. “The jet stream is kind of pushed north so storms aren’t making it into Idaho.”
He also said climate experts are predicting near normal precipitation but above normal temperatures in Idaho over the next several months.
“If we’re much above normal like February and March of last year, our spring snowmelt and runoff could start very early,” he said. “Anywhere to a month to a month and a half ahead of normal.”
Part of the problem for weather and water outlook predictors, they said, has been unusual weather patterns in recent years that make long-standing models somewhat less reliable. That can cause problems for farmers trying to decide what crops to plant. Dam operators are tasked with filling reservoirs but risk flooding downstream if not enough room is available for water from late winter storms.
“What we’re seeing is a greater degree of climate variability,” Abramovich said. “Used to be we’d have a normal snow year and you could count on normal spring precipitation. Now, our winter snowfall is coming in fewer but bigger storms, and we’re also seeing greater temperature variability during the wintertime.”