PROJECT ALERT NOTICE (ND SD) Dakota WSC Flooding

Date: Mon, 06 Apr 2020 11:18:55 EDT

Summary: Summary: Flooding occurring in Eastern North and South Dakota in the Big Sioux, James, and Red River Basins.

Flooding is occurring in the Eastern Dakotas from the SD/NE state line to the Canadian border as much of the remaining winter snowpack melted early last week. Runoff slowed considerably beginning April 2, 2020, as cold air moved into the region while delivering a widespread 6-12 inches of wet snow with 1-2 inches of snow water equivalent (SWE). Storm details are available at the National Weather Service link below. As this new snow melts, secondary peaks comparable in magnitude to the initial snowmelt peaks are expected south of Hwy 2 in ND, while sites north of Hwy 2 will have prolonged crests a bit higher than initial forecasts. The current 5-day Quantitative Precipitation Forecast (QPF) is available here https://www.wpc.ncep.noaa.gov/qpf/p120i.gif?1585750818 and shows only trace precipitation amounts this week.

Storm - https://www.weather.gov/fgf/2020_04_02_HeavySnowIceFlood

The current spatial extent of flooding along with deterministic 7-day forecasts can be found at:

Missouri River Basin https://www.weather.gov/mbrfc/
Red River Basin https://www.weather.gov/ncrfc/

In the Dakotas, 34 sites are currently or soon to be above flood stage with the following breakdown by category:

5 streamgages at major flood stage (James & Red)
19 streamgages at moderate flood stage (James & Red)
10 streamgages at minor flood stage (Multiple Basins)

Eight USGS crews (16 people) are deployed in the James and Red River Basins today from the Bismarck, Grand Forks, and Huron Offices. Crews were off April 2-3 due to hazardous winter travel conditions produced by the storm. Seven crews worked this weekend to measure peaks and restore lost telemetry caused by freezing rain coating the antennas at a dozen sites. Eighty-three flood measurements made in four days last week with seventeen more scheduled for today. Crews today are focused on the eleven RDG sites, establishing shifts at open water sites, and measuring peaks. Ten flood water quality samples have been collected in support of contractual commitments with cooperators with seven more planned for the week. All streamgages in areas of flood are operational. Discharge at stations is being displayed to the public as the impact from ice decreases.

Stakeholders are informed of our activities through updates to NWISWeb, NWSChat, social media, and continued project alerts. Several recent updates have posted on social media showcasing USGS activities during the flood. On Facebook, we're Dakota Water Science Center and on Twitter we're USGS_DWSC.