PROJECT ALERT NOTICE (ND SD) Dakota WSC Flooding

Date: Tue, 26 Mar 2019 17:39:40 EDT

Summary: USGS response to flooding in SD & ND (Day 13).

Gage-heights at forty-three (43) U.S. Geological Survey streamgages in South Dakota (SD) and North Dakota (ND) are exceeding National Weather Service (NWS) minor to major flood stages. The distribution of the forty-three sites experiencing flooding in the Dakotas can be observed at the WaterWatch link below (please note that the use of multiple gage height sensors in ND prevents some sites from clearly displaying the presence of flood conditions in ND at the link below).

*Eastern SD - major flooding on the Big Sioux and James Rivers will continue for some time as melting snow continues to reinforce the current flows. No new PORs are currently forecast for either river, but some sites will remain near POR through at least the weekend. Webcam imagery of the Sioux Falls area is available at https://siouxfalls.org/flood/webcams

*Central and Southwest SD - flows on the Cheyenne River and White River are still very high but no longer rising. Angostura Dam in the Upper Cheyenne has begun decreasing flows and has returned to internal alert response levels. Quinn Dam in Pennington County, SD (865 ac-ft) is in danger of breaching. Any release would end up in the Bad River. The USGS has offered to assist in monitoring should it be needed.

*Northwest SD - flows on the Little Missouri have crested but the Grand and Moreau Rivers are still rising. The POR forecast for the Moreau River at Whitehorse is being carefully monitored. The BOR operated Sladehill Reservoir in the Grand River Basin has reached Response Level 1.

USGS 06360500 MOREAU R NEAR WHITEHORSE, SD
https://waterwatch.usgs.gov/?id=wwsa&site_no=06360500

*Western ND - the Yellowstone River nr Cartwright (06329610) is still at POR due to ice jamming. Hwy 200 continues to remain closed due to water on the road. The Missouri River near Williston is at major flood stage and rising. There is still significant snowpack present south of Bismarck, ND.

*Eastern ND - major flooding is forecasted but little runoff has begun. A slow and gentle melt continues as temperatures oscillate above and below freezing from day to night. The NWS has indicated that Red River of the North flooding is not likely to commence this week.

Approximate annual exceedance probability (AEP) will be provided for various basins once the peaks have passed.

Since the beginning of flood conditions on March 13, 2019, USGS crews in the DWSC have made 107 measurements despite ice and overland flooding challenges. All data section staff in both states are deployed today to measure flows and repair gages. Six real-time sites are currently having operational issues, and many CSGs have been destroyed.

The DWSC has been in contact with the Office of Communications. A local ABC affiliate TV crew met with a field crew in Sioux Falls yesterday.

https://www.ksfy.com/content/news/How-does-Sioux-Falls-keep-track-of-river-levels-507645271.html

An NBC affiliate TV crew met with a field crew today. Stakeholders are being informed of our activities through updates to NWISWeb, NWSChat, email, and phone calls.

Dakota WSC Flood Map