PROJECT ALERT NOTICE (ND) Dakota WSC Flooding

Date: Tue, 19 Mar 2019 14:21:29 EDT

Summary: The hydrologic outlook for the Red River of the North Basin indicates a high potential for major flooding.

The Red River of the North Basin is located on the border between ND and MN and extends into Manitoba, Canada (see link below). Flow is from south to north.

https://prd-wret.s3-us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/atoms/files/rrbasin_final.pdf

Above normal soil moisture in the southern portion of the basin, deeper than normal frost, and a winter snowpack that is much above normal is expected to produce a top ten runoff year (per the NWS in Grand Forks, ND). On March 15, 2019, the NWS released the following hydrologic outlook:

https://www.weather.gov/media/fgf/2019_03_15_Flood_Outlook.pdf

An emergency declaration has already been implemented for the city of Fargo, ND and one million sandbags are being prepared. Additional information on this declaration is available at this news link:

https://www.valleynewslive.com/content/news/Mayor-Mahoney-declares-State-of-Emergency-sets-goal-of-one-million-sandbags-for-Flood-2019-507312361.html

Overland flooding is expected to be a significant issue during the spring runoff as discussed in this news report:

https://www.inforum.com/news/990065-Floodwaters-could-isolate-rural-residents-create-vast-lake-in-Cass-County

The current hydrologic outlook for centennial Red River streamgages at Fargo, ND and Grand Forks, ND indicates a 50% chance of a peak with a 0.02 annual exceedance probability (AEP) or "50-year recurrence interval".

The timing of the runoff continues to be uncertain, but temperatures will be warm enough to ripen the snowpack this week and next, potentially inducing runoff into local drainages late next week. Permanent streamgages are being evaluated to ensure flood readiness and cooperators have been contacted about the need for RDG installations. We have contacted neighboring WSCs to assess their ability to assist. Currently, almost all streamgages are impacted by the presence of ice with discharge not displayed to the public.

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