Rainfall, along with runoff from melting snow from March 23-24, pushed much of the Little Sioux River back above flood stage after a few days below flood stage. Reaches from Milford (MIFI4) to Spencer (SPWI4) to Linn Grove (LNNI4) again had waters invade mainly agricultural lowlands, along with city greenways in Spencer and Sioux Rapids.
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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.
Rainfall, along with runoff from melting snow from March 23-24, pushed much of the Little Sioux River back above flood stage after a few days below flood stage. Reaches from Milford (MIFI4) to Spencer (SPWI4) to Linn Grove (LNNI4) again had waters invade mainly agricultural lowlands, along with city greenways in Spencer and Sioux Rapids.
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 Mar 28, 11:14 AM CST, 46 minutes earlier.
Area Forecast Discussion National Weather Service Sioux Falls SD 1214 PM CDT Wed Mar 28 2018 .SHORT TERM...(Today and Tonight) Issued at 406 AM CDT Wed Mar 28 2018 A short wave current moving across the western and central Dakotas will continue to move eastward through the day. The leading edge of cold front associated with the wave is in central SD at this time, and will have moved through the entire forecast area by between 21Z and 00Z this afternoon. Plenty of moisture will move from west to east from 700mb to 500mb. Whether that is enough to give any measurable light rain chances is a question. Upper level dynamics are not overly strong, however there is some low to mid level frontogenesis tied fairly close with the wind shift. Furthermore the various models are showing some higher based stratus oozing down this afternoon across parts of our northern and eastern zones behind the wind shift from the north. Therefore low end pops for very light rain are still warranted except for perhaps are northwest zones. But overall, measurable rainfall will be hard to find. Behind the cold front, highs today will be cooler than yesterday throughout our western zones. As northerly winds drop off tonight and skies clear, it looks like a good night for radiational cooling, especially across our western zones where winds go very light. However our western zones will also see an increase in mid and high level cloud cover likely moderating their drop. Therefore stayed pretty close to consensus lows. .LONG TERM...(Thursday through Tuesday) Issued at 406 AM CDT Wed Mar 28 2018 Thursday appears to be relatively quiet across the areas as a surface ridge moves through. With 925 hpa temps near 0C and light flow, expect temperatures to remain below normal. Clouds will be on the increase late in the day in advance on mid level wave dropping through in northwest flow. Fairly strong wave could lead to a short duration snowfall. The question is will the intensity of the snowfall be able to overcome the warming surface. Friday will be relatively quiet through the morning hours, but winds will really increase through the afternoon and evening hours ahead of a strong front moving through the area. Great jet dynamics with the forecast area located in the left exit region of jet streak on the backside of the upper trough. Precipitation ahead of the front will most certainly be rain, but could mix with and change to snow behind the front. Winds will most certainly increase behind the front with 30-35 knots at 925 hpa coupled with strong cold air advection. Temperatures could be fairly steady throughout the day on Saturday or potentially fall some depending on the timing of the front. Have highs a few degrees warmer than record low max territory. Temperatures will recover some Sunday into Monday, but another disturbance moves through the area on Monday night. At this point, this system appears to be somewhat disorganized with limited amounts of moisture. In addition, precip type could be a bit of an issue, with lack of saturation in the near surface layer and in the dendritic layer. Temperatures look to remain below normal through the remainder of the extended, with another wave moving through Tuesday night into Wednesday. Models at this point are really differing on the track and intensity of this system, so have left blended pops as is for now. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1210 PM CDT Wed Mar 28 2018 A weak front will move through the region this afternoon, changing south and southwest winds to breezy north and northwest winds gusting to 25 kts. A couple hours of very light rain showers is possible as the front moves through, but dry air in the surface layers will minimize accumulations. Behind the front, MVFR stratus cloud decks are expected for the overnight hours, with light north winds continuing overnight into Thursday morning. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && SHORT TERM...MJ LONG TERM...BT AVIATION...VandenBoogart
Hazardous Weather Outlook National Weather Service Sioux Falls SD 430 AM CDT Wed Mar 28 2018 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-NEZ013-014-SDZ038>040-050-052>071-290930- Lyon IA-Osceola-Dickinson-Sioux-O'Brien-Clay IA-Plymouth-Cherokee- Buena Vista-Woodbury-Ida-Lincoln MN-Lyon MN-Murray-Cottonwood- Nobles-Jackson-Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury- Brookings-Gregory-Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora- Davison-Hanson-McCook-Minnehaha-Charles Mix-Douglas-Hutchinson- Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union- 430 AM CDT Wed Mar 28 2018 This Hazardous Weather Outlook is for portions of northwest Iowa, west central Iowa, southwest Minnesota, northeast Nebraska, central South Dakota, east central South Dakota, south central South Dakota, and southeast South Dakota. .DAY ONE...Today and Tonight Minor flooding is occurring on several local rivers and creeks due to recent rainfall and melting snow. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday A weather disturbance will move through the region Thursday night into Friday morning. Snow amounts ranging from dusting to an inch are possible with this system. A strong cold front is expected to move through the region Friday night. As this front moves through, rain may transition to snow. Minor snow accumulations are possible. Minor river flooding may continue much of the week. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
6 flood. Local standard time, as filed.
Snow melt runoff on top of already high river levels produced minor flooding of lowland agricultural areas along upper portions of the Little Sioux River. River levels reached 2.3 feet above flood stage at Spencer (gage site SPWI4) by the end of the month.
Snow melt runoff on top of already high river levels produced minor flooding of lowland agricultural areas along upper portions of the Little Sioux River. River levels reached 0.9 feet above flood stage near Milford (gage site MIFI4) by the end of the month.
Snow melt runoff on top of already high river levels produced minor flooding of lowland agricultural areas along upper portions of the Little Sioux River. River levels reached 0.9 feet above flood stage near Milford (gage site MIFI4) by the end of the month.
Snow melt runoff on top of already high river levels produced minor flooding of lowland agricultural areas along middle portions of the Little Sioux River. River levels reached 0.4 feet above flood stage near Linn Grove (gage site LNNI4) by the end of the month.
Snow melt runoff on top of already high river levels produced minor flooding of lowland agricultural areas along middle portions of the Little Sioux River. River levels reached 0.4 feet above flood stage near Linn Grove (gage site LNNI4) by the end of the month.
Snow melt runoff on top of already high river levels produced minor flooding of lowland agricultural areas along middle portions of the Little Sioux River. River levels reached 0.4 feet above flood stage near Linn Grove (gage site LNNI4) by the end of the month.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2018Every state in 2018This day in weather historyWarnings in Iowa, March 2018
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 2026-09-24. Each event’s entry at NCEI: 759914, 759904, 759911, 759916, 759918, 759920.