Water Resources of the United States
Date: Fri, 01 Jun 2018 17:09:15 EDT
Summary: Final alert for the May 2018 floods in NE Washington
The last of the major rivers in the Upper Columbia Basin in northeast Washington has peaked ending the May 2018 snowmelt flood event. The Pend Oreille River has been rising slowly for the entire month of May and crested yesterday at 121,000 cfs. It is still above the moderate flood stage but the flows are forecasted to drop below the lower flood level by June 9th. During this flood the Kettle River set a peak of record at both USGS-operated gages on May 10-11 and both gages have 90 years of record. Also, the Okanogan River at Oroville set a peak of record on May 13, and its record goes back to 1942. Both the Similkameen River near Nighthawk and the Okanogan River near Tonasket gages have records going back to 1929, and this year’s peaks (May 10th and May 11th) were the 3rd highest peak for both sites. Many other rivers on the east side of the Washington Cascade Mountains also had high peak flows earlier in the month and have been receding since then. Crews out of the Upper Columbia Field Office have been busy this month maintaining gages with only minimum loss of record and making several highest-ever discharge measurements at several of the sites they operate.