Low W. Oregon snowpack may impact summer irrigation
For the Capital Press
With half the snowfall season in the books, snowpack levels in Western Oregon are dangerously low.
The good news is the levels could rebound before snowfall season expires, and in Eastern Oregon, where farmer fortunes are more closely tied to snowpack, the levels are doing fine.
Still, with the warm, wet conditions of an El Nino permeating Western Oregon at a time when the snowpack is typically building, concerns are mounting that Western Oregon farmers could face water shortages come irrigation season.
“We’ve seen years where snowpack levels rebounded,” said Scott Oviatt, snow program manager for the Natural Resources Conservation Service in Portland. “We’ve also seen years where the tap just shut off.”
Last year, Oviatt said, snowpack levels were below even this year’s in the January survey. But heavy, late-season snowfall created near normal snowpack levels by May.
Oviatt said the NRCS attributes the low snowfall levels in Western Oregon this year to “climate variability” and not climate change.
“Climate variability is the key here, and that is the case every year,” he said.
The lowest levels in the first NRCS Oregon snow survey of the year are in the Klamath Basin, which is at 24 percent of normal; the Rogue Umpqua Basin, which is at 25 percent of normal; and the Willamette, which is at 29 percent of normal. Also dangerously low are the Hood, Sandy, Lower Deschutes Basin comes in at 30 percent of normal; and the Upper Deschutes, Crooked Basin registers 38 percent of normal.
Snowpack conditions improve dramatically to the east, with Harney Basin at 108 percent of normal; Malheur at 92 percent of normal; and Owyhee at 86 percent of normal. The Umatilla, Walla Walla, Willow Basin is at 68 percent of normal; the Grande Ronde, Powder, Burnt, Imnaha Basin is at 78 percent of normal; while the Lake County, Goose Lake Basin is at 57 percent of normal.
Precipitation levels, conversely, are high throughout the state, with all 11 basins surveyed at or above 100 percent of normal for the water year, which starts Oct. 1.
The NRCS issues snow surveys using data from its 80 Oregon Snotel sites once a month from January through June.
One last hope for Western Oregon farmers, if snowpack levels don’t rebound, is a flush of spring rain to build reservoir levels. Given that weather forecasters are showing warmer than normal conditions over the next 90 days, heavy spring rainfall may end up being Western Oregon farmers’ last and best hope to generate a water supply adequate to get through the 2015 irrigation season.