With gradually cooling temperatures, river levels continued to drop slowly through February. Gaging sites set records for continuous days in flood at Huron (328 days), Forestburg (336 days) and Mitchell (343 days).
Every event with a place to put it. Tap one for its entry below.
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.
With gradually cooling temperatures, river levels continued to drop slowly through February. Gaging sites set records for continuous days in flood at Huron (328 days), Forestburg (336 days) and Mitchell (343 days).
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 Jan 31, 11:06 PM CST, 54 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 1106 PM CST Fri Jan 31 2020 .SHORT TERM...(This Evening through Saturday) Issued at 357 PM CST Fri Jan 31 2020 In the vicinity of the weak surface trough limping across southwest MN and northwest IA at mid-afternoon, there remains an abundance of fog, although fairly little of it with visibility less than a mile. Stratus extends westward of the James River, but has been ever so slowly eroding eastward. As the weak surface ridge axis in south central SD progresses eastward, should continue to see an eastward shift to the boundary. Unfortunately, the high clouds have won the battle, and effectively shrunk the wedge of potential clearing to near nothingness, with just a few glimpses of filtered sun west of the lower James River valley. It is possible that areas on the western edge of the stratus experience a little more favored for some lowering visibility in fog, but given the degree of high clouds for now have shied away, and kept fog mainly near the surface convergence zone, then redeveloping mainly in west-southwest upslope favored zones during the evening/overnight. With the abundance of clouds, have nudged temps up just a bit from the previous forecasts. Upper ridge sliding eastward into the Plains on Saturday will be led by a strong pulse of warm advection. Isentropic lift is meager with the aggressively translating isentropic surfaces, so even with a band of mid-level moisture working through, the combination of the short duration of usable lift and the dry air below cloud layer likely to keep things dry. While would not be out of the question for a sprinkle or two toward Highway 14 tomorrow later morning- midday, unlikely enough to keep out of a mention. The big story about Saturday will be the warming, as work toward some increased sunshine behind the initial cloud band. It is so warm aloft, that the bust potential on temps walks a fine line with every few hundred feet of mixing likely numerous degrees of temperature. With such a strong inversion, unlikely to make much of this potential, with exception of the western Missouri River areas where likely to make a run at 60 degrees in parts of Gregory county. Elsewhere, made use of the local snowcover climatology to take temps above the 75th percentile which falls mainly into the lower to mid 40s. Gradient is in fact quite strong aloft, so the stable near surface layer probably keeping most areas from gusting to 25 to 35 mph, which would be most likely to surface near higher elevations. .LONG TERM...(Saturday Night through Friday) Issued at 357 PM CST Fri Jan 31 2020 Wind direction is not optimal on Saturday night for maximum coupling (too west/northwest to fully interact with terrain) , but a trend toward a downstream ridge wind enhancement appears likely as winds as low as 1000-1500ft AGL increase to 45 to 50 knots. A very mild night likely with only some earlier night decoupling potentially allowing temps as lower as the lower to mid 30s. Sunday will find a strong wave moving along the Canadian border into the northern Great Lakes, and the wave responsible will drive a cold front southward across the area. Timing of this feature has been fairly inconsistent, and the ultimate timing will have impact on the warming potential. Likely will start the day poised north of the area, moving rapidly southward through early afternoon. It should be a day of fairly thick higher clouds, as cooling aloft weakens the overall inversion. Competing effects here on the mixing potential, but would think the mechanical should likely win out to some degree. Raw model guidance seems to be impacted too greatly by snow cover and therefore represents a vast majority of colder solutions in the distribution, while the statistically based guidance is consistently among the warmer cluster. Have removed the coldest NAM (which ties much of the surface to 32-35F through the day) and then repopulated with closer to the recalculated 75th percentile MaxT. The colder air will settle in for the first half of the week, as a strong surface ridge settles southward into the northern Plains within the confluence of the northern/southern streams. Fairly good agreement on the larger scale that a deep trough dropping into the southwestern U.S will begin to eject out, shearing, as it moves toward the confluence zone. Some considerable differences in where the main baroclinicity will settle as the system moves out Tuesday into Wednesday, and how much impact the drying from the north will impede any developing frontal band of snowfall. For now, the better chances remain across the southern portions of the area, perhaps on a couple surges with initial setup and saturation from aloft late Monday into Monday night, and then Tuesday into Tuesday night as the main upper jet pulls out across the central Plains. Tempwise, Tuesday should be the coolest with mainly upper teens to lower 20s for highs, with a slight moderation to the 20s to lower 30s on Wednesday. While details vary, models indicate increased northwest flow following this system will likely bring a clipper system into the region around the later Thursday into early Friday window with another threat for light snowfall. In the meantime, temps will work back to near to a bit above normal to end the week. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1102 PM CST Fri Jan 31 2020 Pesky low-end MVFR-LIFR stratus and BR expected to slowly decrease in coverage through daybreak Saturday as weak westerly low level flow brings drying across the region. Once sub-VFR conditions are eradicated by mid-late morning, focus turns to increasing winds above surface-based inversion which will lead to low-level wind shear spreading across eastern South Dakota in the afternoon, and most of the forecast area Saturday evening. West-northwest winds atop the inversion likely in the 40-45kt range, possibly reaching 50kt at times after sunset. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && SHORT TERM...Chapman LONG TERM...Chapman AVIATION...JH
Hazardous Weather Outlook National Weather Service Sioux Falls SD 408 PM CST Fri Jan 31 2020 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-SDZ039-040-055-056-062-067-071-012215- Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee- Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson- Pipestone-Rock-Kingsbury-Brookings-Lake-Moody-Minnehaha-Union- 408 PM CST Fri Jan 31 2020 This Hazardous Weather Outlook is for northwest Iowa, west central Iowa, southwest Minnesota, east central South Dakota and southeast South Dakota. .DAY ONE...Tonight. Areas of fog will continue into tonight. Some could be locally dense around the Buffalo Ridge into early evening. As temperatures dip below freezing tonight, slick spots could occur as standing moisture freezes on roadways. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. NEZ013-014-SDZ038-050-052>054-057>061-063>066-068>070-012215- Dixon-Dakota-Beadle-Gregory-Jerauld-Sanborn-Miner-Brule-Aurora- Davison-Hanson-McCook-Charles Mix-Douglas-Hutchinson-Turner- Bon Homme-Yankton-Clay- 408 PM CST Fri Jan 31 2020 This Hazardous Weather Outlook is for 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. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The national radar mosaic for the moment the first event began.
6 flood. Local standard time, as filed.
A continuation of flooding from January, the James River at Huron (HURS2) began the month at 0.49 feet above flood stage. Minor flooding of rural areas upstream of the gage slowly ended as river levels dropped below flood stage by mid-month.
A continuation of flooding from January, the James River near Forestburg (gage site FORS2) started the month at 1.14 feet above flood stage. A few county and township roads near the gage remained in flood until the river fell below flood stage on February 20.
A continuation of flooding from January, the James River near Mitchell (gage site JRMS2) began the month at 1.23 feet above flood stage, with a slow drop in levels before falling below flood stage on February 19. The main impact was continued flooding of agricultural land near the river.
A continuation of flooding from January, the James River near Mitchell (gage site JRMS2) began the month at 1.23 feet above flood stage, with a slow drop in levels before falling below flood stage on February 19. The main impact was continued flooding of agricultural land near the river.
A continuation of flooding from January, the James River near Mitchell (gage site JRMS2) began the month at 1.23 feet above flood stage, with a slow drop in levels before falling below flood stage on February 19. The main impact was continued flooding of agricultural land near the river.
A continuation of flooding from January, the James River near Mitchell (gage site JRMS2) began the month at 1.23 feet above flood stage, with a slow drop in levels before falling below flood stage on February 19. The main impact was continued flooding of agricultural land near the river.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2020Every state in 2020This day in weather historyWarnings in South Dakota, February 2020
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: 874708, 874709, 874727, 874733, 874734, 874735.