Heavy rain caused minor to moderate flooding of the Little Sioux and Ocheyedan Rivers. Farmland, other lowlands, and a few roads were affected.
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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.
Heavy rain caused minor to moderate flooding of the Little Sioux and Ocheyedan Rivers. Farmland, other lowlands, and a few roads were affected.
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 Sep 24, 2:39 AM CST, 3 hours 21 minutes earlier.
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 340 AM CDT FRI SEP 23 2010 .DISCUSSION... CLEARING OF LOW CLOUDS EXPECTED TO PROCEED STEADILY FROM THE SW THIS MORNING INTO ERY AFTN. SHORT TERM MODELS INCLUDING THE NAM12 AND RUC SEEM TO HAVE A FAIR HANDLE ON THE CLEARING WHEN LOOKING AT THE H9 RH. THEY MAY BE A LITTLE TOO ERY...LOOKING AT LATEST STLT UPSTREAM THE CLOUDS SEEM TO BE BREAKING OUT MORE FROM THE NEW OVER ND THAN RECEDING FROM THE SW. THIS WUD SUGGEST THE CLEARING MIGHT BE A LITTLE LATER BUT FASTER WHEN IT DOES HAPPEN. IN ANY EVENT...MOST OF THE FORECAST ARE SUD BECOME SUNNY/MOSUNNY BY NOON WITH THE NERN CRNR HOLDING ONTO THE CLOUDS A LITTLE LONGER. HIGH TEMPS WILL BE KIND OF COOL WITH 60S NORTH AND E TO LOWER 70S SW WHERE THE WHOLE DAY WILL BE GENERALLY SUNNY. STRONG NERLY WINDS WILL SLOWLY DECREASE. IT WILL BE FAIRLY WINDY FOR A CHUNK OF THE DAY IN SWRN MN...BUT WITH WINDS JUST BLO ADVISORY CRITERIA NOW WILL NOT GO WITH WIND ADVY. SHORTWAVE DIGGING OVER AREA LATER TONIGHT AND SAT ON ITS WAY TO FORMING UPPER LOW S/SE OF AREA WILL HAVE GOOD DYNAMICS AND SHEAR BUT MEAGER MOISTURE. SOME HALF DECENT SHOWERS AND A FEW TSTMS ARE STILL EXPECTED LATE TONIGHT AND SAT MORNING...THRU SAT AFTN FAR E. LOOKS LIKE THE MEAGER MOISTURE WILL PREVENT ANY THREAT OF SEVERE STORMS OR HEAVY RAIN...THOUGH ISOLD STORMS MAY PRODUCE SMALL HAIL AS PER SPC OUTLOOK. THE SHOWERS AND TSTMS SHOULD MOVE OUT OF FAR ERN/SERN FCST AREA BY END OF SAT...WILL KEEP A SLIGHT CHC SHWRS ERY SAT EVE FAR SERN CORNER IN PART OF NWRN IA UP TO MJQ IN SWRN MN. TEMPS OF COURSE WILL BE COOL WITH THIS SYS SAT AT LEAST IN THE EAST. AS UPPER LOW DIGS S/SE OF FORECAST AREA...STRONG UPPER RIDGING OVER WRN NOAM SHOULD FORGE ITS WAY INTO THE PLAINS. THIS WILL RESULT IN AN EXTENDED DRY PERIOD WITH SEASONABLY COOL TEMPS QUICKLY BECOMING MILD. PSBL WEAK FRONTS MON AND WED ARE ASSOCIATED WITH WAVES PROGGED TO PASS WELL N/NE OF AREA OVER RIDGING AND AIR WILL BE QUITE DRY SO THE FORECAST WILL BE ALSO. / WILLIAMS && .AVIATION... MVFR CIGS ACROSS FORECAST AREA EARLY MORNING WILL TREND TOWARD GOING SCATTERED AT TAF SITES BY 14Z ON THE WAY TO SKC DURING THE AFTERNOON AND EARLY EVENING. INCREASING MID EVENING CLDS FROM THE NORTHWEST WITH AREAS OF MVFR CIGS DEVELOPING IN SHOWERS AND ISOLATED -TSRA AFTER 25/06Z. MODERATE NORTHWEST SURFACE WINDS SUBSIDING DURING THE AFTERNOON. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && WILLIAMS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SIOUX FALLS SD 426 AM CDT FRI SEP 24 2010 SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098- IAZ001>003-012>014-020>022-031-032-NEZ013-014-251200- AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA- CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE- DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON- IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN- LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN- OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN- SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON- 426 AM CDT FRI SEP 24 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA... SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP FROM THE NORTHWEST TONIGHT...MAINLY AFTER MIDNIGHT. NO SEVERE STORMS ARE EXPECTED AT THIS TIME. FLOODING... FLOODING OF SEVERAL RIVERS AND STREAMS WILL CONTINUE TODAY IN THE WAKE OF HEAVY RAINS OF WEDNESDAY AND THURSDAY. THESE INCLUDE MAJOR RIVERS SUCH AS THE JAMES...VERMILLION...BIG SIOUX AND LITTLE SIOUX. IN ADDITION...WIDESPREAD AREAL FLOODING CONTINUED THIS MORNING IN SOUTHWEST MINNESOTA...AND IN SOME AREAS NEAR THE MINNESOTA BORDER IN EAST CENTRAL SOUTH DAKOTA AND NORTHWEST IOWA. FLOODING OF LOW AREAS INCLUDING ROADS AND FLOODING OF SMALL STREAMS WILL BEGIN TO ABATE SLOWLY TODAY. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS SATURDAY...MAINLY EAST OF THE JAMES RIVER...WILL DECREASE FROM THE WEST SATURDAY AFTERNOON. SEVERE STORMS ARE NOT EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY AND TONIGHT. && FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WWW.WEATHER.GOV/SIOUXFALLS. THIS INCLUDES THE GRAPHICAL HAZARDOUS WEATHER OUTLOOK. WILLIAMS
The national radar mosaic for the moment the first event began.
4 flood. Local standard time, as filed.
Heavy rain caused minor to moderate flooding along the Little Sioux River, with farmland and other lowlands affected. A few roads were also flooded. The river crested at 4 feet above flood stage near Milford on September 27th.
Heavy rain caused minor flooding along the Little Sioux River, with farmland and other lowlands affected. The river crested at 1.5 feet above flood stage at Spencer on September 27th.
Heavy rain caused minor flooding along the Ocheyedan River, with farmland and other lowlands affected. The river crested at just under a foot above flood stage near Spencer on September 26th.
Heavy rain caused minor flooding along the Little Sioux River, with farmland and other lowlands affected. The river crested at less than a foot above flood stage at Linn Grove on September 27th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2010Every state in 2010This day in weather historyWarnings in Iowa, September 2010
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: 262622, 262623, 262625, 262626.