Rapid snowmelt from a few day period of well above normal temperatures focused on the 11-13th of April resulted in minor to locally moderate flooding through much of the Big Sioux River Basin. Some areas north of I-90 lost between 2 to 5 inches of snow water equivalent (SWE) from the first to second week of April but antecedent drought conditions resulted in only a percentage of this water…
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FSD wrote it up.
Rapid snowmelt from a few day period of well above normal temperatures focused on the 11-13th of April resulted in minor to locally moderate flooding through much of the Big Sioux River Basin. Some areas north of I-90 lost between 2 to 5 inches of snow water equivalent (SWE) from the first to second week of April but antecedent drought conditions resulted in only a percentage of this water actually making it into the river system.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sioux Falls, SD wrote its last area forecast discussion before the first event at Apr 8, 5:36 PM CST, 24 minutes earlier.
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</html>The national radar mosaic for the moment the first event began.
4 flood. Local standard time, as filed.
Sixmile Creek above Brookings, SD rose above flood stage on the evening of April 8th before cresting around 0.95 feet above flood stage (1634.95 feet) on April 12th. The creek then fell below flood stage on the evening of April 12th.
Flandreau Creek near Flandeau, SD rose above flood stage on the early morning of April 9th before cresting around 0.28 feet above flood stage (9.28 feet) on April 9th. The creek then quickly fell below flood stage midday on April 9th.
Split Rock Creek near Corson, SD rose above flood stage on the evening of April 9th before cresting around 1.74 feet above flood stage (10.24 feet) on April 9th. The creek then fell below flood stage on the morning of April 10th.
Medary Creek near Medary, SD rose above flood stage on the morning of April 10th before cresting around 0.47 feet above flood stage (1588.47 feet) on April 10th. The creek then fell below flood stage on the morning of April 12th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2023Every state in 2023This day in weather historyWarnings in South Dakota, April 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 1091988, 1091992, 1091998, 1091989.