Late Season Snow Helps Lagging Snowpacks

March 12, 2018

Idaho water outlook mostly positive


Good carryover storage across southern Idaho should provide adequate irrigation water, while supplies in parts of central Idaho are marginal.


Snowpack across Idaho ranges from 120 percent of normal in the Clearwater Basin to 40 percent of normal in the Owyhee Basin.


With only a month of winter remaining, some areas could use more precipitation, said Ron Abramovich, water supply specialist with the Natural Resources Conservation Service in Boise.

Fortunately, a return to winter weather at the end of February brought low temperatures and storms, and conditions are changing, he said.


A warm, dry spell in January bled into February, leaving central and southern Idaho drier than normal, he said.


“A lot of the moisture fell after the first of March,” he said.


But above-average carryover and good reservoir storage across southern Idaho should be adequate for irrigation supplies, he said.


Snowpack in the Upper Snake Basin is 100 percent to 120 percent of normal, and there will be plenty of water to fill reservoirs and numerous other needs, he said.


But water supplies could be marginal in the Big Wood, Little Wood, Big Lost and Little Lost basins, he said.


A good storm visited those areas last weekend, dumping up to 2 feet of snow in some mountain locations. But those basins need another storm or two to ensure adequate irrigation supplies, he said.

And if snow doesn’t fall in the Owyhee and Bruneau basins yet this winter, those areas could use rain this spring, he said.


Abramovich and NRCS water specialists are working on their latest water supply outlook report, which will be available by week’s end.


Oregon snowpack rebounding, but still below average


Snowpack is improving in Oregon heading into March, but still below average in every basin across the state.


February was a tale of two seasons for Oregon’s snow-starved mountains and river basins.

The first half of the month saw warm and dry weather carry over from December and January, with total snowpack languishing around 40 percent of normal levels statewide. But winter has come roaring back over the last few weeks, doubling the amount of snow on the ground across some areas, especially in the northern Oregon Cascades.


Julie Koeberle, snow survey hydrologist for the USDA Natural Resources Conservation Service in Portland, said the amount of snow at Mount Hood rose from 53 inches on Feb. 11 to 118 inches, showing an impressive turnaround.


“It’s been really interesting,” Koeberle said. “What we waited all season to get, we pretty much got in the last two weeks.”


While conditions are much improved, Koeberle cautions snowfall is still lagging behind on average.

“We still need quite a bit more if we’re going to catch up to normal,” she said.


Portions of southern Oregon are in particularly dire straits, with the Klamath and Owyhee basins still registering below 50 percent of normal snowpack. Klamath County commissioners have already declared a drought emergency, and farmers are bracing for a painful year.