PORTLAND, Ore. - All basins in Oregon are experiencing above-normal to well-above-normal snowpack, with a statewide average of 38 percent above normal, according to the March water supply outlook report released Tuesday by the USDA Natural Resources Conservation Service.
Snowpack conditions have been above normal all winter for most locations in the state, the agency said.
February continued to be an active month for winter weather in Oregon, with well-above average precipitation statewide, even breaking previous records in some locations. With limited sunshine and continued cold temperatures, the mountains received above-normal to well-above-normal February snowpack accumulation.
The last time Oregon had a well above normal snowpack on March 1 was in 2008, when the snowpack was 157 percent of normal. Last year, Oregon’s snowpack was 94 percent of normal at the end of February.
“Snow accumulation during February was twice the normal amount at many monitoring locations, leading to a well-above-normal statewide snowpack on March 1,” said Scott Oviatt, NRCS snow survey supervisory hydrologist. “Moderate February temperatures helped preserve the deep snowpack even during a few warm days and significant rain in some cases.”
The peak of the seasonal snow accumulation generally occurs during March for many low and mid elevation sites in the state. Thus far, snow monitoring sites in this elevation band have already met or surpassed normal peak snowpack amounts. In general, the higher elevation sites have not met their normal peak amount as they do not typically reach peak until April.
For the 2017 water year, all basins have experienced well-above-average precipitation. Lake County and Goose Lake basins have had the most, at 152 percent of average, while the Mt. Hood, Sandy and Lower Deschutes basins have had only 111 percent of the usual amount of precipitation.
“With the continued accumulating snowpack, streamflow volume forecasts show promise for the spring and summer,” Oviatt said. “However, there is still some time left in the season that will dictate the water supply outlook for 2017. As of March 1, the streamflow volume forecasts are calling for near-average to well-above-average summer streamflows during the water supply season throughout the state.”
As of the end of February, there is wide variety of reservoir storage throughout the state, as reservoir operators manage the need for flood control space and storage for summer water supplies. Of particular note is Lake Owyhee, which is 128 percent of average after several years of well-below-normal volumes. The lake is now storing over 500,000 acre-feet for the first time since 2012.
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 recreationists 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 information for all SNOTEL sites nationwide is available on the Snow Survey website in a variety of formats. The reports are updated every hour and are available at: www.or.nrcs.usda.gov/snow
NRCS publishes six monthly Oregon Water Supply Outlook Reports between Jan. 1 and June 1 every year. To regularly receive this information as an email announcement, visit the Oregon NRCS Snow Survey website and click the “email updates” icon to subscribe.