Date: Tue, 17 Jun 2014 08:34:03 EDT
Summary: Major flooding in lower Big Sioux River basin
Major flooding is occurring in southeastern South Dakota on the lower Big Sioux with minor flooding within the Vermillion River basin. Prior to the weekend, the lower Big Sioux and Vermillion Rivers were flowing in the upper 75th-quartile for this time of year, Additional rains fell over the weekend, some locally heavy. On Monday, June 16, locally heavy rains fell resulting in additional flooding in, around, and south of the Sioux Falls area. Precipitation totals for the Monday storms ranged from 2-5 inches with 5 day totals in the 6-9 inch range. NWS is reporting 8-10 inches over much of Lincoln County (estimate by radar). Interstate 90 east of Sioux Falls into MN was closed due to the weekend rains resulting in flood waters over the road and Interstate 29 south of Sioux Falls was closed Monday night due to flood waters over the roadway.
To date, no streamgages have exceeded peaks of record, Currently 3 South Dakota streamflow gages within the Big Sioux River Basin remain above flood stage, most having peaked. The Big Sioux River at Akron (06485500) continues to rise and is forecast to peak at 24.4 ft, a new record stage, however, likley not a new record discharge. Streamgages in the Vermillion River basin continue to rise but have not reached floodstage with forecasts of peaks near flood stage.
USGS flood activities include field operations by 2 crews making flood measurements, inspecting gages for damages and possbily flagging high water marks. Measurements are being provided to the NWS and COE.