As of Tuesday, February 13, 2018
Paltry snowpack on Mount Hood spells some unknowns for valley irrigation this year.
Steve Castagnoli, director at the local Oregon State University experiment station, said rain levels have been almost normal but snowpack has fallen behind its usual amount.
As data from the Hood Basin gathered by three Natural Resources Conservation Service test sites show, “although we’ve had close to average precipitation to date, the snowpack (snow water equivalent) is well below average,” he said.
Castagnoli said the low snow levels may constrain irrigators in the Hood River Valley.
“Unless there is a significant change in weather resulting in more snow for the rest of the winter and early spring, I would expect that water supplies for irrigation will be tight this season,” he said.
Julie Koeberle, NRCS snow hydrologist, said Feb. 8 the agency’s sites around Mount Hood found 45 percent of median snowpack.
“So we’re looking at less than half of normal,” she said.
The agency refers to snowpack as a loose term, meaning the amount of water that’s stored in the snow — not how deep it is. Hydrologists also measure snow depth, but they do not compare those figures to any normal amount, Koeberle explained.
Koeberle said the Hood basin has experienced fairly usual precipitation since the water year began Oct. 1, but there have been “more warm storms than cold storms conducive for snowpack building.”
Much of Oregon faces poor snowpack, according to an NRCS basin report published Feb. 1.
The report found that a cold and snowy start to the winter was followed by meager snowfall and warm temperatures in December and January, “stunting” mountain snowpack.
Out of 137 long-term snowpack monitoring sites measured for the report, all recorded less than normal snowpack and most were
less than half of normal for Feb. 1.
“With about half of winter behind us, chances for a full snowpack recovery are low, but there is still time left for conditions to improve before the typical peak of the snowpack season in March and April,” NRCS officials said.
The report contained a summary for the Hood, Sandy and Lower Deschutes basins. All stations in the region showed lower snowpack than last year, though levels varied.
The Mt. Hood Snotel test site at 5,370 feet on Feb. 1 had a snow depth of 74 inches, while the snow water equivalent (snowpack) was 61 percent of median. Similarly, the Red Hill site at 4,410 feet showed a snow depth of 54 inches and snowpack of 69 percent of median.
Other sites at lower elevations on the mountain, such as Clackamas Lake, had half of median snowpack or lower.
Streamflow forecasts in the basin for April through September range from 85 percent to 92 percent of average. If conditions remain similar, water supplies in the basin will likely wane below ordinary this summer, the report noted.
Much depends on the spring weather outlook.
Koeberle said, “If conditions stay similar, most streams and rivers will experience below normal streamflow this summer. We still have a couple of months left in the snow season, so we are hopeful that we get a miracle March or a cool and wet springtime.”