In most basins across the state, Oregon’s mountain snowpack remains at near normal to above-normal levels and continues to surpass last year’s peak levels, according to the March Water Supply Outlook Report released by the USDA Natural Resources Conservation Service (NCRS).
On March 4, the NRCS reported that the statewide average snowpack was 92 percent of normal.
Portions of Eastern Oregon are experiencing the highest snowpack levels due to above-normal precipitation that fell as snow throughout January. Additionally, cooler temperatures at higher elevations have retained the snowpack from earlier in the season.
In Western Oregon, snowpack is the lowest in the state in the Mount Hood and Willamette Basins, at 77 percent and 76 percent, respectively.
February was very warm, with above normal temperatures statewide. Most basins experienced some mid and low elevation snowmelt during warmer periods in the middle of the month. Higher elevations continued to gain snow during February and are retaining the snow for now. As the spring weather approaches, warmer temperatures and rain-on-snow events could result in significant snowmelt run-off.
“Temperature will be the key indicator for March snowpack development and retention, since warmer conditions have already resulted in low and mid-elevation snowmelt run-off in several locations,” said Scott Oviatt, NRCS Oregon snow survey supervisor. “Eastern Oregon continues to see the best conditions in the state, due to cooler mountain temperatures.”
According to the March report, streamflow forecasts call for slightly-below-average to slightly-above-average volumes for the summer water supply season. Southeastern Oregon has some forecast points well above average, however the highest forecasts are for the Deschutes and Crooked rivers. However, hydrologists continue to caution that if current warm conditions prevail, summer projections are likely to change.
The latest information on Oregon’s streamflow forecasts can be found in the March Water Supply Outlook Report available on the NRCS Oregon website.
The NRCS Snow Survey is the federal program that measures snow and provides streamflow forecasts and snowpack data for communities, water managers and recreationalists across the West. In Oregon, snow measurements are collected from 81 SNOTEL sites, 42 manually measured snow courses, and 26 aerial markers. Water and snowpack data for all Oregon SNOTEL sites are available online in a variety of formats. The reports are updated every hour and are available at: www.or.nrcs.usda.gov/snow.