1 flash flood, as filed by the National Weather Service.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 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 15, 2:35 AM CST, 1 hour 55 minutes earlier.
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 335 AM CDT CDT WED SEP 15 2004 .DISCUSSION.. MAIN SHORT TERM FORECAST PROBLEMS ARE ONGOING WEATHER TODAY AND ITS IMPACTS ON TEMPERATURES AND FOG POTENTIAL TONIGHT. 07Z WATER VAPOR IMAGERY INDICATED STRONG SHORTWAVE TROUGH ENTERING WESTERN NEBRASKA WITH STRONG H300 DIFFLUENCE AHEAD OF FEATURE. WIDESPREAD PRECIP WAS SEEN ON MOSAICS BOTH ALONG THE COLD FRONT AND WARM FRONT. MODELS ALREADY BEGAN TO DIVERGE WITH HANDLING OF THIS FEATURE IN THE FIRST SIX HOURS OF THE FORECAST WITH GFS SEEMING TO BE A BIT CONVECTIVELY CONTAMINATED. EXPECT WAVE TO SLOW A BIT OVER THE NEXT FEW HOURS AS IT INTERACTS WITH FRONTAL ZONE AND CYCLOGENESIS INCREASES. THAT BEING SAID BEST SHOT OF PRECIP AFTER 12Z LOOKS TO BE IN THE NORTHEAST CWA...WITH PRECIP CHANCES DROPPING OF FAST TO THE SOUTH AFTER 13Z. ALTHOUGH THE RAIN WILL CONTINUE A BIT LONGER TODAY WONT CONTINUE FLOOD WATCH AS HEAVIEST RAINS HAVE ALREADY FALLEN...AND WILL JUST HAVE TO COVER THINGS WITH WARNINGS AS NEED BE. WAVE LOOKS TO CLEAR ENTIRE CWA AND STRONG SUBSIDENCE SETS IN. THIS SHOULD SCOUR OUT CLOUDS PRETTY QUICKLY SAVE FOR SOME WRAP AROUND STRATUS TO THE NORTHEAST. TEMPS SHOULD MIX OUT TO H850 PRETTY EASY IN THE SOUTH WITH LOTS OF SUNSHINE AND POST FRONTAL WIND...BUT WILL PROBABLY ONLY BE A FEW DEGREES WARMER THAN NOW IN THE NORTHEAST. TONIGHT SFC RIDGE SETTLES OVER AREA DROPPING OF WINDS. WITH ABUNDANT LOW LEVEL MOISTURE...INVERSION STRENGTHENING BY LL WARM ADVECTION AND WEAK BL WINDS...EXPECT TO SEE A GOOD RADIATIONAL FOG EVENT OVERNIGHT. DENSE FOG WILL ALSO BE POSSIBLE ACROSS THE SE AS WEAKEST WINDS WILL OCCUR AT TIME OF MAX RADIATIONAL COOLING. DESPITE GOOD COOLING...THINK MODELS ARE UNDER DOING SFC MOISTURE AND WILL GO NOT AS COLD AS GUIDANCE. AFTER THURSDAY MORNING WX SHOULD BE QUIET THROUGH SATURDAY. MODELS CONTINUE TO SHOW A SERIES OF SHORTWAVES SLIDING CROSS THE AREA THU-SAT. BUT SFC RIDGE TO THE SOUTH WILL SERIOUSLY IMPEDE ANY DECENT MOISTURE RETURN SO WILL CONTINUE DRY FORECAST. DID ADD SOME SMALL POPS ON SUNDAY AS STRONGER RETURN FLOW SETS UP...BUT MADE NO MAJOR CHANGES TO REST OF THE FORECAST. .FSD...WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. NE...NONE. IA...NONE. && JRM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SIOUX FALLS SD 1147 AM CDT TUE SEP 14 2004 SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098- IAZ001>003-012>014-020>022-031-032-NEZ013-014-151200- 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- 1147 AM CDT TUE SEP 14 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA... SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS... THUNDERSTORMS WILL REDEVELOP NEAR A VERMILLION TO SPENCER IOWA LINE AFTER 4 PM THIS AFTERNOON. SOME STORMS MAY BECOME SEVERE LATE THIS AFTERNOON AND EARLY THIS EVENING ALONG AND SOUTH OF A VERMILLION TO SPIRIT LAKE LINE. VERY HEAVY RAINFALL...HAIL THE SIZE OF HALF DOLLARS AND WIND GUSTS TO 60 MPH ARE THE MAIN THREATS. AN ISOLATED TORNADO WILL ALSO BE POSSIBLE ALONG AND JUST SOUTH OF THIS FRONT. THE THREAT FOR TORNADOES WILL BE MAINLY SOUTH OF A SIOUX CITY TO LINN GROVE LINE. FLOODING... THUNDERSTORMS THAT DEVELOP THIS AFTERNOON AND EVENING OVER NORTHEAST NEBRASKA...NORTHWEST IOWA...FAR SOUTHEAST SOUTH DAKOTA AND FAR SOUTHERN MINNESOTA WILL HAVE THE POTENTIAL TO PRODUCE VERY HEAVY RAINFALL. SOME LOCATIONS COULD SEE AMOUNTS OF 2 TO 4 INCHES...WITH HOURLY RAINFALL RATES APPROACHING TWO INCHES. A FEW RIVERS....CREEKS AND STREAMS COULD APPROACH BANKFULL AND URBAN FLOODING WILL ALSO BE POSSIBLE. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL BE LIKELY AFTER 500 PM CDT. && FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WWW.CRH.NOAA.GOV/FSD. THIS INCLUDES THE GRAPHICAL HAZARDOUS WEATHER OUTLOOK. 08
The Sioux Falls radar (KFSD), 139 km away, was scanning. The volume nearest the first event began at 10:29 UTC.
1 flash flood. Local standard time, as filed.
Rainfall of 3 to 5 inches brought the total since the previous evening began to over 10 inches in the Spencer and Royal areas. The rain caused widespread and severe flooding of roads, including highway 18 just west of Dickens. Basements, small streams, farmland, and other low areas were also flooded.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2004Every state in 2004This day in weather historyWarnings in Iowa, September 2004
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: 5424523.