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Cool, showery April keeps Oregon snowpack in fine shape

Best snowpack in six years, experts say

PORTLAND, Ore. - This year, April showers aren’t just bringing May flowers — they’re also setting the stage for an excellent water supply season this spring and summer, officials said Friday.

All basins in Oregon are maintaining above normal snowpack for this time of year, with a statewide average of 155 percent as of May 1, according to the latest water supply outlook report released Friday by the USDA Natural Resources Conservation Service in Oregon.  

Throughout the month of April, cool temperatures and normal snowmelt rates helped to offset the rapid, widespread snowmelt that occurred in March. Although low and mid elevations have experienced significant snowmelt, high elevation snow monitoring sites show the snowpack continuing to build. 

“We haven’t had a snowpack with this kind of coverage throughout the entire snow season since 2011,” said Julie Koeberle, a hydrologist with the NRCS Oregon snow survey team. “This winter’s cold storms, including several atmospheric rivers that brought copious amounts of precipitation, built large reserves of snow in all of Oregon’s mountain ranges throughout the entire snow season.

"Snowpacks across the state accumulated much more snow than normal at the peak of the season this year, which means we are likely to see above average flows in our streams and rivers this summer.”

Conditions this May look vastly different than the last several drought-stricken years, when May 1 statewide snowpack averaged 62 percent in 2014, 11 percent in 2015 and 64 percent in 2016.

April precipitation was well above average for the fifth consecutive month. The wettest region in April was the Owyhee and Malheur Basin, where precipitation fell at 149 percent of normal. Even the region receiving the lowest amount of precipitation in April (the Klamath basin at 124 percent) has seen above normal water year-to-date precipitation at all monitoring locations.

Months of above-average precipitation, coupled with significant snowmelt in March, has filled many of Oregon’s reservoirs. As of May 1, reservoirs across the state are experiencing normal or above normal levels for this time of year. Many reservoirs are at capacity and are releasing water over spillways for the first time in several years. 

Get more details on Oregon’s streamflow forecasts in the May 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 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.


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