A combination of snow melt and rainfall brought middle portions of the Big Sioux River above flood stage in early March. Crests were at minor flood stage near Hawarden (HWDI4) and Akron (AKRI4), impacting only lowland agricultural areas.
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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.
A combination of snow melt and rainfall brought middle portions of the Big Sioux River above flood stage in early March. Crests were at minor flood stage near Hawarden (HWDI4) and Akron (AKRI4), impacting only lowland agricultural areas.
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 6, 5:24 PM CST, 4 hours 36 minutes earlier.
Area Forecast Discussion National Weather Service Sioux Falls SD 524 PM CST Tue Mar 6 2018 .SHORT TERM...(This evening through Wednesday) Issued at 255 PM CST Tue Mar 6 2018 Massive upper level low dropping south with snow and blowing snow coming to an end. This is allowing for a little melting this afternoon, especially north of Interstate 90 where clouds have cleared. This clearing will work south through late afternoon and evening as the drying wraps south. This should bring a period of clear to partly cloudy skies along and east of the James River this evening into the overnight hours with increasing clouds after this. This will allow temperatures to fall a little, but with winds remain somewhat strong through the night temperatures will not fully radiate. Lows should mainly be in the teens. A relatively weak upper level wave in Montana will move southeast overnight into Wednesday. This will bring an increase in clouds as well as a small threat for light snow. Will maintain the low chances across the area as accumulations are not very likely. Highs will be in the 20s to around 30. .LONG TERM...(Wednesday night through Tuesday) Issued at 255 PM CST Tue Mar 6 2018 Mostly clear skies will develop on Wednesday night as cold high pressure settle south. With fresh snow cover, decreasing winds and mostly clear skies fairly good radiational cooling is expected. Lowered lows with the mid James Valley dropping to around zero and single digits expected in most other locations. The exception will be parts of northwest IA and southwest MN where a little wind and cloud cover could keep lows from 10 to 15 above. Temperatures should warm nicely on Thursday under a partly cloudy sky and light winds. There will be a bit of a limit to the warming however with the cold start, fresh snow cover and cool high pressure still influencing the area. Highs again in the mid 20s to lower 30s. The colder air will linger into Friday before finally shifting east on Saturday. Temperatures will not be a lot warmer over the weekend, but should begin a gradual recovery into early next week as an upper level ridge builds into the area. There is a good chance to be pretty mild next Tuesday through Thursday if we can melt off enough snow the next 5 or 6 days. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 516 PM CST Tue Mar 6 2018 Clearing continues to work its way southward, having already made its way into KHON and KFSD, and should at least briefly make its way into KSUX. MVFR ceilings will quickly fill back in this evening/overnight from the west and continue into Wednesday. A few flurries or very light snow showers are possible during the daytime hours tomorrow but low confidence in their occurrence and extent preclude any mention in the TAF at this time. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && SHORT TERM...08 LONG TERM...08 AVIATION...Kalin
Hazardous Weather Outlook National Weather Service Sioux Falls SD 417 PM CST Tue Mar 6 2018 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-NEZ013-014-SDZ038>040-050-052>071-072230- 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- 417 PM CST Tue Mar 6 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...Tonight No hazardous weather is expected at this time other than some patchy blowing snow in rural areas through this evening. .DAYS TWO THROUGH SEVEN...Wednesday through Monday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Heavy rainfall along with snow melt caused minor flooding of lowland agricultural areas along middle portions of the Big Sioux River. The river reached a crest of 1.7 feet above flood stage near Hawarden (gage site HWDI4) on March 7.
Heavy rainfall along with snow melt caused minor flooding of lowland agricultural areas along middle portions of the Big Sioux River. The river reached a crest of 0.1 feet above flood stage near Akron (gage site AKRI4) on March 8.
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: 759799, 759800.