PROJECT ALERT NOTICE (MN) Flooding in Minnesota, day 10

Date: Wed, 19 Apr 2023 19:18:49 EDT

Summary: Flooding from near record snowpack across Minnesota transitions to mainstem rivers.

Most tributaries have peaked while mainstem rivers continue to rise including the Red River of the North, Rainy, St Croix, Minnesota, Mississippi Rivers. These mainstem rivers are forecast to begin peaking in the next few days and continue into the following days or weeks.

Currently 38 are above NWS flood stage; with 18 above moderate flood stage and 3 above major flood stage. The NWS forecasts 6 gages will peak above major flood stage during the current forecast period.

One gage in Voyaguers National Park and near the Canadian border stopped telemetering last night: 05129290 Gold Portage Outlet from Kabetogama Lake near Ray, MN. Unfortunately, the gage cannot be accessed safely for repairs until the ice goes out from Kabetogama Lake.

Today 10 stream gaging staff from Minnesota were in the field statewide making discharge measurements and repairing gages. Office staff have supported field efforts, communicated with other agencies including the NWS & USACE via NWSChat, responded to emails and phone calls. Since flooding began in earnest April 10, over 90 discharge measurements have been made, 2 stage-discharge ratings have been extended, 2 sites have been flagged for possible indirect measurements, a few sites have lost orifice lines, and many crest-stage pipes have been lost or damaged to ice out. Most peaks to date have estimated Annual Exceedance Probabilities of 0.1 - 0.50. However, 05291000 Whetstone River at Big Stone City, SD peak had an AEP <0.01.

News media have been interested in USGS gaging station webcams installed since our last major flood in 2019. This afternoon Ben Torrison and James Fallon were interviewed by the NBC-affiliate KARE-11 Minneapolis about gage webcams and their utility. That interview is set to air tonight on their extended “Breaking the News” segment at 6:30PM
Other media previously posted USGS time lapse videos ice going out and rivers rising, including the Minneapolis Star Tribune https://video.startribune.com/watch-rivers-rise-rapidly-across-minnesota/600267080/
and Minnesota Public Radio https://www.mprnews.org/story/2023/04/12/river-levels-flooding-forecasts-minnesota-map

The forecast calls for about an inch of precipitation statewide over the next 2 days, but the rain seems to be extending forecasted flood peaks rather than raising them.