Oregon’s snowpack is getting a much-needed boost statewide, thanks to a recent wave of winter storms that since the beginning of February have dumped several feet of new snow in the Cascade Range, including 3 feet on Mount Hood and 2 feet near Crater Lake National Park.
The entire state has seen a 20 to 30 percent bump in snowpack and 2 to 3 times the normal precipitation since Feb. 1, said Julie Koeberle, a hydrologist with the USDA Natural Resource Conservation Service.
That is contrary to the long-term weather forecast, which called for warmer and drier conditions across the Pacific Northwest.
“I’m not sure we saw this increase coming,” Koeberle said. “It was really a pleasant surprise.”
As of Feb. 15, Oregon’s total snowpack was 93 percent of average, compared with 73 percent at the end of January and a paltry 40 percent at this time last year.
Snowpack is critical to the state’s farmers and ranchers, many of whom rely on summer snowmelt to replenish the rivers, streams and groundwater that feed the state’s irrigation systems.
Eastern Oregon is well ahead of the curve, with basins ranging between 114 and 132 percent of snow-water equivalent — that is, the amount of water in snow available to replenish streams and reservoirs.
Despite more snow falling in the Cascades, Western Oregon still has some catching up to do, especially in the Hood, Sandy and Lower Deschutes basins, at 77 percent of average, and in the Willamette Basin, at 83 percent of average snowpack.
The Rogue and Umpqua basins have climbed to 91 percent of average, and 96 percent in the Klamath Basin.
“We’d like to see these storms continue,” Koeberle said. “If that does not happen, the best-case scenario would be to preserve the snowpack we just gained.”
The good news is that more snow and rain is expected through the weekend across Oregon, even with the arrival of a weak El Nino climate pattern that typically indicates warm and dry weather in the region.
Mike Halpert, deputy director of the National Oceanic and Atmospheric Administration’s Climate Prediction Center, said there is a 55 percent chance El Nino conditions will continue through spring.
However, he added that the pattern is expected to be weak, “meaning we do not expect significant global impacts through the remainder of winter and into the spring.”
Even in El Nino, David Bishop, meteorologist with the National Weather Service in Portland, said that does not necessarily exclude more winter weather.
“Just because we are in a weak El Nino does not mean that we cannot get snow, or cannot get (low) temperatures,” Bishop said.
Koeberle, with the NRCS, said Oregon usually reaches peak snow season in late March or early April, depending on the elevation. Last year, unseasonably warm weather caused snow to melt earlier than usual, exacerbating the summer drought.
“If we do end up losing our snow early, then we could hope for spring rainfall to help offset those impacts,” Koeberle said.
As long as the snow continues to fly, Koeberle said water supplies should look improved for summer 2019. The most recent Oregon Basin Outlook Report, released on Feb. 1, predicted stream flows from 70 to 90 percent of normal statewide, and reservoirs storing between 63 and 93 percent of average. The NRCS will issue its next report on March 1.
“We do have another month and a half before the typical peak of our snow season,” Koeberle said. “At least right now, the trend is going up and hopefully that will continue.”