Widepsread moderate to heavy rain at the end of march led to minor to moderate flooding on the Big Sioux, Little Sioux, and Ocheyedan Rivers during the first week of April.
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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.
Widepsread moderate to heavy rain at the end of march led to minor to moderate flooding on the Big Sioux, Little Sioux, and Ocheyedan Rivers during the first week of April.
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 1, 4:25 AM CST, 1 hour 35 minutes earlier.
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 525 AM CDT SUN APR 1 2007 .DISCUSSION... FIRST THINGS FIRST...ENDED FLOOD WATCH AS THREAT OF ADDITIONAL SHORT FUSED FLOODING HAS ENDED...AND NOW HAVE TRANSITIONED OVER TO RIVER STREAM FLOODING FROM EXCESSIVE RUNOFF. UPDATED SEVERAL FLOOD WARNING EARLIER IN NIGHT...AND EXPECT ONCE GET MORE SOLID IDEA OF PRECIP COVERAGE...WILL BE MAKING FURTHER UPDATES THIS MORNING. EARLY PART OF FCST WL BE DEALING WITH WINDING DOWN THE WRAPPED UP PCPN BANDS... THEN WITH NEXT SYSTEM MONDAY INTO TUE. COLLAPSE OF BRIGHT BANDING TOWARD RADAR SITE HAS CORRESPONDED WELL WITH A LITTLE SNOW STARTING TO MIX IN TO W/SW OF KFSD EARLY THIS MORNING. EARLIER HAD MIXED/CHANGED ARND MO RVR...AS COLD CORE ALFT WRAPS ARND SW FLANK OF UPR LOW. EXPECT BAND DEFINED ROUGHLY BY 295/300K ISENTROPIC SFCS WL PULL TO NR JAMES VALLEY BY 12Z... I29ISH LATE MORNING...AND INTO SW MN EARLY AFTN AS DEMISE ACCELERATES WITH DRY AIR INGESTION. STRIKING HOW QUICKLY MDLS ADVERTISE WARMING IN WAKE TODAY AS COLDER AIR REALLY TIGHT AROUND LOW CENTER. WL TEMPER TENDENCY TO WARM UP TOO QUICKLY...PARTICULARLY IN AREAS WHERE PCPN OCCURRING THRU MUCH OF MORNING...AND CLOUDS WL BE EVEN A BIT SLOWER TO DEPART. AFTER ALL...AT LEAST A COUPLE INCHES OF RAINFALL HAS OCCURRED OVER A GOODLY SHARE OF CWA...AND WL NOT BE AN EASY THING TO MAKE IT WARM UP TO POTENTIAL WHICH WOULD BE MID TO UPPER 50S BASED ON 925 HPA TMPS. WINDY IT WILL BE FOR MUCH OF DAY... BUT GRADIENT RELAXES SOMEWHAT DURG AFTN AND BETTER MIXING SHUD GET CUT OFF BY WARMING ALFT. TONIGHT...GRADIENT FALL APART TO NOTHING BY 06Z...AND EXPECT WNDS TO VANISH ALMOST AS FAST. MOISTURE SEEMS TO BE SHALLOWED OUT TOO MUCH IN VIEW OF RECENT RAINFALL AND WITH NO DECENT SOURCE OF SIGNIFICANT DRYING...SO WL AT LEAST THROW IN SOME PATCHY FOG LATE TONIGHT. LITTLE SUGGESTION IN MDLS OF FRONTAL FORCING IN MID LVLS TONIGHT INTO EARLY MONDAY THRU MO VLY...BUT RIDGING ALFT IS FAIRLY FORMIDIBLE SO WL KEEP TO JUST AN INCREASE IN MID CLOUDS FOR NOW. DIVERGING SLNS ONCE AGAIN FOR MONDAY. WAVE DIGGING OFF BC THIS MORNING WL BE THE ONE TO SLIDE TOWARD THE NRN PLAINS...WITH NAM FASTER. EC/GFS/CANADIAN ARE VERY CLOSE INDEED. SREF IS NOT TOO CERTAIN ON LOCATION OF FEATURES BY MON AFTN/EVNG... LEADING EVEN MORE SKEPTICISM TO NAM SLN. THRU MORNING...STRONGER FRONTAL FORCING SETS UP FAVORING AREAS MAINLY N OF I 90...ESPLY FAR NRN TIER. NOT ENTHUSIASTIC ABOUT THUNDER THREAT...BUT BY AFTN THE FRONTAL BAND STARTS TO GET A LITTLE BETTER INTERACTION WITH UPR JET EXIT... SO WL PUT IN ISOLD WHILE POPS RAMP UP EARLY AFTN TO LKLY IN N. COULD VERY WELL SEE A TIGHT LOW LVL BAROCLINIC ZONE NR MO RVR LATER IN DAY MORNING...SO WL CONTINUE A STRONG MAX TEMP GRADIENT...AND KEEP LATE DAY CHC OF THUNDER SOMEWHAT SEPERATE FROM EARLIER MID LVL FRONTOGENETICALLY FORCED THREAT. MONDAY NIGHT...WL CONTINUE MODERATE POPS AS MAIN SFC WAVE MOVES FM NE INTO IA...PULLING INVERTED TROUGH EWRD THRU CWA. STRONG JET DYNAMICS SEEM TO FAVOR NRN CWA...SETTING UP PCPN GRADIENT. HOWEVER... LOW LVL BNDRY WANDERING TOWARD NW IA...AND WL HAVE TO WATCH LT AFTN/EVENING CONVECTION FOR OUTSIDE SVR THREAT ACRS ERN CWA...AS ELEVATED MIXED LAYER AND GOODLY DOSE OF DEEP SHEAR EVOLVES. TUE...MAY NOT SEE A GREAT DEAL OF THERMAL CLIMB AS STRONG CAA TAKES OVER. LINGERING PCPN WL BE MOST LKLY ACRS N/NE CWA EARLY IN DAY BEFORE MAIN WAVE MOVES EWRD...AND WOULD NOT BE SHOCKED FOR LIGHT ACCUMULATIONS ALG/N A KHON/KMWM LINE. AGAIN TOOK THE RED MARKER TO TMPS MIDWEEK AND CUT BACK WITH EVERY MODEL COMING UP SHY ON FULL 850 HPA MIXING TO GOING READINGS. && && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...NONE. && CHAPMAN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SIOUX FALLS SD 551 AM CDT SUN APR 01 2007 SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098- IAZ001>003-012>014-020>022-031-032-NEZ013-014-021200- 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- 551 AM CDT SUN APR 01 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA... SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA. .DAY ONE...TODAY AND TONIGHT FLOODING... RUNOFF FROM RECENT HEAVY RAINFALL WILL CAUSE MANY RIVERS TO RISE ABOVE FLOOD STAGE IN THE NEXT COUPLE OF DAYS...AND REACH MINOR TO MODERATE FLOOD CRESTS LATER IN THE WEEK. RIVERS EXPECTED TO FLOOD INCLUDE THE JAMES...VERMILLION...BIG SIOUX...LITTLE SIOUX...AND OCHEYEDAN. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY LATE MONDAY AFTERNOON AND MONDAY EVENING...SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP IN AREAS ALONG AND SOUTH OF A LINE FROM YANKTON TO SIOUX FALLS TO JACKSON. SOME OF THESE STORMS COULD BECOME SEVERE WITH LARGE HAIL AND DAMAGING WIND. LATER IN THE NIGHT AND THROUGH TUESDAY MORNING...COLDER AIR WILL CHANGE RAIN TO SNOW... WITH POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS ALONG AN AXIS FROM HURON TO WINDOM. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WWW.CRH.NOAA.GOV/FSD. THIS INCLUDES THE GRAPHICAL HAZARDOUS WEATHER OUTLOOK. CHAPMAN
The national radar mosaic for the moment the first event began.
4 flood. Local standard time, as filed.
Heavy rain at the end of march led to minor to locally moderate flooding along the Big Sioux River. Lowlands including some farmland near the river were flooded.
Heavy rain at the end of march led to minor to locally moderate flooding along the Big Sioux River. Lowlands including some farmland near the river were flooded.
Heavy rain at the end of March led to minor flooding along the Little Sioux and Ocheyedan Rivers. Some lowlands along the rivers were flooded but no significant damage was reported.
Heavy rain at the end of March led to minor flooding along the Little Sioux River. Some lowlands along the river were flooded but no significant damage was reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2007Every state in 2007This day in weather historyWarnings in Iowa, April 2007
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: 30024, 30025, 30026, 30027.