Photo by David Rauzi
South Fork of the Clearwater, pictured at Castle Creek in July.
As of Tuesday, January 16, 2018
Regionally, the water season is above average for the region, while for Idaho overall it is off to a slow start, according to the Natural Resources Conservation Service’s (NRCS) first outlook report for the 2018 year.
Precipitation since the water year started on Oct. 1, 2017, varies across the state with watersheds ranging from 70 to 130 percent of normal.
“September gave us a good start on snowpack, but December was pretty dry, with only a third of the normal precipitation across Idaho’s west-central and central mountains,” said Ron Abramovich, NRCS water supply specialist. “The good news for water users is that last year’s high snowpacks and runoff primed the hydrologic system and has kept rivers and springs flowing above average well into this fall and early winter.”
For the Clearwater River Basin, October and early November precipitation was well above normal, allowing above normal snowpack accumulation until Thanksgiving. Warmer temperatures then brought rain in all elevations across the region for a few days, melting out some of the accumulated snow. After a three-week stretch of minimal precipitation, large mid-and late-December storms allowed the snowpack to rebound in all basins, leaving the region with an above-normal current snowpack.
According to the outlook report, the Clearwater Basin received 119 percent of normal precipitation for the October through December period.
For snowpack, the Lochsa River Basin is at 130 percent of normal (up 34 percent from this same time last year), the Selway River at 127 percent (up 31 percent), and the North Fork Clearwater River at 106 percent (up 15 percent).
Dworshak Reservoir is currently at 65 percent total capacity, which is 94 percent of average for this time of year.
As of Jan. 1, streamflow forecasts are slightly above normal for the runoff season.
“We’re not quite halfway through the season, and a lot could change.” Abramovich said. “La Nina conditions are present in the Pacific Ocean, and this typically means that there will be wetter conditions in the second half of the winter in the Pacific Northwest.”