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News Release

April rain and warmth rev up Oregon’s snowmelt

NEWS_RELEASE_HEADER-UPDATEDRelease No.: 2019-05-028

Contact:
Scott Oviatt, Snow Survey Supervisory Hydrologist
503‐414‐3271, scott.Oviatt@or.usda.gov

Julie Koeberle, Snow Survey Hydrologist
503-414-3272, julie.koeberle@or.usda.gov

PORTLAND, Ore. – (May 8, 2019) — Flooding, unusually warm weather, and record streamflows defined the month of April according to the latest Water Supply Outlook Report released today by the USDA Natural Resources Conservation Service.

Numerous records were broken for both total April precipitation and streamflow volumes for the month. As temperatures warmed later in the month, spring snowmelt began in earnest and many snow monitoring sites experienced more than double the usual amount of snowmelt for the month.

“A wet spring assisted in balancing out earlier periods of lower precipitation,” said Scott Oviatt, Snow Survey supervisory hydrologist. “Water users that have access to reservoir storage will likely have adequate water supplies this summer, while those dependent upon in-stream flows will need to continually monitor conditions due to rapidly changing weather patterns.”

From snow to flow

In general, snow monitoring sites in eastern and southern Oregon reached higher than normal peak levels of snow this winter at 100-160 percent of normal. Basins in western and central Oregon peaked slightly lower at 90-130 percent of normal.

Heavy rain and rapid snowmelt fueled by warm weather led to record high April streamflows and flooding in many parts of the state. Snow melted at two to four times the normal rate at many monitoring sites. Despite rapid melt rates, most basins in eastern Oregon are still holding above normal amounts of snow as of May 1.

Downpour

Western and northern Oregon basins received the most precipitation relative to normal at 165-200 percent. Twenty-one monitoring sites and 10 National Weather Service Sites set new record highs for April precipitation. Several of these new records were set at weather stations that have been measuring precipitation for over 90 years, such as Riddle 2 NNE, outside of Riddle, Ore. which had the wettest April in its 106-year period of record.

As heavy rain and snowmelt swelled creeks and rivers across the state, reservoir managers faced the difficult task of balancing flood control with storage for summer months. Most reservoirs statewide are storing near average to above average amounts of water.

For a basin-by-basin streamflow forecast and guidance on interpreting streamflow forecasts, view the complete May Water Supply Outlook Report.

About snow survey

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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