PORTLAND — Oregon’s snow season was shortened by early snowmelt, even after most of the state’s mountains achieved near normal to above normal seasonal snowpack. Warm temperatures and rapid snowmelt during April resulted in an unusual amount of snowpack loss, even breaking records in some cases, according to the June Water Supply Outlook Report released today by the USDA Natural Resources Conservation Service.
May provided a return to more seasonable temperatures, but the majority of the snow had already melted from most basins by May 1. The rapid flush of early snowmelt caused many rivers to reach their snowmelt-driven streamflow peaks earlier than normal.
“The early snowmelt has resulted in streamflows peaking sooner and beginning to recede to midsummer levels up to four weeks early,” said NRCS Snow Survey Supervisor Scott Oviatt.
“Water year precipitation (since Oct. 1) has been near to above normal across the state, and has boosted reservoir levels that were near record low at the end of last summer,” Oviatt said. “This paints a much better picture for water supply this year, compared to last year when reservoir storage was well below average. However, if the summer is hot and increases demand, water users drawing from reservoir sources could still experience possible water shortages.”
Streamflow forecasts for the summer are calling for below normal to well below normal residual streamflow volumes. Streamflow forecasts in Southeast Oregon are the lowest in the state with most of the forecasts less than 60 percent of average.
Find the latest information on Oregon’s streamflow forecasts in the June 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
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.