5 feet on April 29th around 2 am. 64 feet around 9 pm April 30.
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 DVN wrote it up.
Heavy rains during the last week of April resulted in the Iowa River at Marengo going above the moderate flood stage level of 15.5 feet on April 29th around 2 am. It crested around 17.64 feet around 9 pm April 30. It stayed in moderate flooding through the end of the month.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at Apr 28, 2:05 PM CST, 10 hours 55 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 305 PM CDT TUE APR 28 2009 .SYNOPSIS... LATEST SFC ANALYSIS WAS INDICATING A LOBE OF RIDGING EXTENDING SOUTHWESTWARD THROUGH IA AND INTO THE SOUTHEAST PLAINS FROM CENTER JUST NORTH OF LK SUPERIOR. LLVL CYCLOGENESIS AND DEVELOPING TROF COMPLEX WAS ONGOING TO THE LEE OF THE ROCKIES AND UP ACRS THE NORTHWEST HIGH PLAINS...WITH INCREASING SOUTHEASTERLY RETURN FLOW JUST TO THE EAST OF THAT PROCESS. ALOFT...H85 MB BOUNDARY DRAPED ALONG AND SOUTH OF THE DVN FCST AREA WAS SHOWING SIGNS OF STALLING IN RESPONSE TO LLVL CYCLONE DEVELOPING OVER THE INTER-MOUNTAIN REGION JUST SOUTHEAST OF MAIN H5 MB UPPER LOW. OTHERWISE...BROAD SOUTHWESTERLY STEERING FLOW PATTERN CONTINUED ACRS MUCH OF THE CONUS. && .SHORT TERM...TONIGHT AND WEDNESDAY... MAIN CHALLENGE IN THE NEAR TERM WILL BE A TRICKY CLOUD FORECAST AND IMPACT THIS WILL HAVE ON SFC TEMPS TONIGHT AND INTO TOMORROW. STRATOCU THAT HAS SLOSHED BACK FROM THE EAST IN EASTERLY LLVL FLOW OVER MUCH OF THE SOUTHERN 2/3S OF THE DVN CWA...PLUS ANY MORE DIURNAL CELLULAR CU THAT HAS DEVELOPED IN ANY CLEARING THAT HAS OCCURRED...WILL HAVE A GOOD CHANCE TO BE TRAPPED BY A BUILDING SUBSIDENCE INVERSION OVERNIGHT/ACCORDING TO FCST SOUNDINGS/. BUT THE DRYING AND SUBSIDING EAST-NORTHEAST FETCH WILL ALSO BE TRYING TO ERODE ANY LOW CLOUDS FROM THE NORTHEAST AT THE SAME TIME THIS EVENING. WILL PLAY CLOUD COVER MORE PESSIMISTIC TONIGHT AND GO CLOUDY/MOSTLY CLOUDY EXCEPT FOR THE FAR NORTHWESTERN CWA...BUT SOME VEERING TRENDS IN LLVL FLOW AS THE NIGHT PROGRESSES AROUND PASSING RIDGE LOBE MAY EVENTUALLY ADVECT CLOUDS UP IN THOSE AREAS AS WELL. SOME HIGHER LEVEL DEBRIS CLOUDS MAY ALSO STREAM ACRS IN MID TO UPPER LAYER WESTERLY FLOW. WILL PLAY LOW TEMPS WITH THE CLOUD COVER BLANKET SCENARIO AS WELL...BUT MAY GO COOLER THAN GUIDANCE IN THE FAR NORTHEAST TOWARD LOWER DPTS AND INITIAL CLEAR AREAS. AS TEMPS COOL TOWARD DPTS...WILL BANK ON CLOUD COVER TO LIMIT ANY DENSE FOG DEVELOPMENT. BUT WITH LIGHT EAST SOUTHEAST FLOW LATE TONIGHT...ANY POTENTIAL BREAKS IN THE CLOUD COVER OVER RAIN SATURATED AREAS MAY HAVE THE CHC TO FOG UP. POTENTIAL FOR SOME BREAKS IN THE LLVL CLOUDS WORKING IN FROM THE NW MO SUBSIDENCE REGION TO MAKE THEIR WAY INTO PORTIONS OF THE SOUTHERN CWA AND WILL ADD PATCHES OR AREAS OF FOG MENTION IN THOSE AREAS AFTER MIDNIGHT. ON WEDNESDAY...LLVL RETURN/MOISTURE FLOW THAT IS NOW ORGANIZING UP THE WESTERN PLAINS WILL EDGE CLOSER TO EASTERN IA AND NORTHEAST MO BY AFTERNOON. WHILE THE BULK OF THE BEST/MORE ORGANIZED LOW TO MID LEVEL THTA-E ADVECTION AND CONVERGENT ZONES FOCUS OFF TO THE WEST OF THE DVN CWA WED AFTERNOON...SEVERAL MODELS AND ESPECIALLY THE NAM ARE PICKING UP ON A LEAD CONVERGENT SIGNAL AND SOME INSTABILITY IN THE VCNTY OF DEVELOPING WARM FRONT ACRS NORTHERN MO BY LATE AFTERNOON. WILL KEEP SLIGHT CHC POPS GOING IN THE FAR SOUTHERN AND WESTERN FRINGES WED AFTERNOON WITH AN ADJUSTMENT TO ADD MORE THUNDER WORDING IN THE SOUTH IN MID LAYER INSTABILITY PLUME JUST NORTH OF THE LLVL WARM FRONT. NEXT SHIFT MAY HAVE TO CONTEMPLATE STRAIGHT CHC POPS BY LATE AFTERNOON IN THE FAR SOUTH AND SOUTHWEST. AS FOR TEMPS... EXPECT A MAINLY CLOUDY/MC DAY ON WED. BUT WITH SOME BREAKS AND MIXING SOUTHEAST FLOW ENHANCEMENT...TEMPS COULD WARM WELL UP INTO THE MID TO UPPER 60S. IF NO BREAKS OCCUR...CURRENTLY FCST TEMPS WILL BE TOO MILD. ..12.. .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY... WARM AIR ADVECTION REGIME PRECIPITATION SHOULD BE GETTING WELL UNDERWAY...SPREADING QUICKLY NORTHEAST ACROSS THE FORECAST AREA WEDNESDAY EVENING. THE CONSENSUS OF THE FORECAST MODELS CONTINUES TO INDICATE THE POTENTIAL FOR AN MCS TO DEVELOP WEDNESDAY EVENING AND PROGRESS NORTHEAST...GENERALLY ACROSS THE SOUTHEAST HALF OF THE FORECAST AREA LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. MODERATE TO HEAVY RAINFALL IS ANTICIPATED WITH THIS SCENARIO ACROSS THE SOUTHEAST HALF OR SO OF THE FORECAST AREA. SOME SCATTERED SHOWERS MAY LINGER DURING THE AFTERNOON AND EARLY EVENING HOURS THURSDAY...BEFORE INCREASED PRECIPITATION CHANCES RETURN THURSDAY NIGHT INTO FRIDAY MORNING. THE WARM FRONTAL BOUNDARY IS FORECAST TO BE LAID OUT WEST TO EAST ACROSS THE FORECAST AREA ON THURSDAY...WITH A TRAILING COLD FRONT FROM CENTRAL IOWA BACK ACROSS NORTHEAST KANSAS. THE NEXT ROUND OF SHOWERS AND THUNDERSTORMS...WITH THE POTENTIAL FOR ANOTHER DEVELOPING MCS IS EXPECTED THURSDAY NIGHT...WITH THE APPROACH OF A RATHER POTENT UPPER SHORTWAVE TROUGH. SEVERE THUNDERSTORMS WILL ALSO BE A POSSIBILITY THURSDAY NIGHT...WITH PORTIONS OF SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS OUTLOOKED WITHIN A SLIGHT RISK AREA. THIS SYSTEM WILL ALSO BRING YET ANOTHER THREAT FOR HEAVY RAINFALL. THE SHOWERS AND THUNDERSTORMS SHOULD COME TO AN END BY LATER IN THE DAY FRIDAY...ONCE THE COLD FRONT PASSES THROUGH THE AREA. TEMPERATURES FOLLOWING THE FRONT ARE EXPECTED TO RETURN TO WITHIN A COUPLE DEGREES OF NORMAL FOR THE WEEKEND. THE MAIN UPPER TROUGH WILL SHIFT EAST ACROSS THE EASTERN GREAT LAKES/OHIO VALLEY DURING THE WEEKEND. THIS WILL LEAVE WEAK SHORTWAVE RIDGING TO NEAR ZONAL FLOW TO SPREAD ACROSS THE FORECAST AREA. DRY WEATHER IS ANTICIPATED AT LEAST FOR THE FIRST HALF OF THE WEEKEND AS SURFACE HIGH PRESSURE BUILDS IN. THE MEDIUM RANGE FORECAST MODELS BEGIN TO DIVERGE BY LATE WEEKEND/EARLY NEXT WEEK. THERE ARE INDICATIONS THAT SHORTWAVE DISTURBANCES WILL MOVE INTO PORTIONS OF THE MIDWEST AGAIN...BUT THE PLACEMENT OF THE SMALLER SCALE FEATURES REMAINS IN QUESTION FOR NOW. ..STOFLET.. && .AVIATION... CLOUD COVER OF VARYING MVFR AND LOW VFR CIGS AND ANY CLEARING POTENTIAL MAKE FOR A TRICKY TERMINAL FCST TONIGHT. WILL BANK ON CLEARING FOR THE EVENING ANYWAY OF LOW CLOUDS AT DBQ AND CID... UNTIL SOUTHEAST FLOW ADVECTS CLOUDS BACK LATER TONIGHT OR REFORM UNDER SUBSIDENCE INVERSION UNDER 2K FT. WILL KEEP MVFR TO LOW VFR CLOUDS TRAPPED AT MLI AND BRL...WITH THE BRL TERMINAL AT RISK OF EXPERIENCING IFR CIGS AFTER 06Z. ANY BREAKS WOULD FOSTER AT LEAST SOME AVIATION FOG AFTER 05Z AT ALL TERMINALS...AND BRL/CID MORE PRONE TO POTENTIAL IFR VSBYS...AGAIN MAINLY AFTER THE 05-06Z TIMEFRAME. SOME DIURNAL CIG RISE EXPECTED TO HIGH LEVEL MVFR OR LOW VFR BY LATE WED MORNING IN AREAS THAT GET LLVL CLOUDS TRAPPED ALL NIGHT. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && 12/STOFLET
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 500 AM CDT TUE APR 28 2009 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-291000- BENTON IA-BUCHANAN IA-BUREAU IL-CARROLL IL-CEDAR IA-CLARK MO- CLINTON IA-DELAWARE IA-DES MOINES IA-DUBUQUE IA-HANCOCK IL- HENDERSON IL-HENRY IA-HENRY IL-IOWA IA-JACKSON IA-JEFFERSON IA- JO DAVIESS IL-JOHNSON IA-JONES IA-KEOKUK IA-LEE IA-LINN IA-LOUISA IA- MCDONOUGH IL-MERCER IL-MUSCATINE IA-PUTNAM IL-ROCK ISLAND IL- SCOTLAND MO-SCOTT IA-STEPHENSON IL-VAN BUREN IA-WARREN IL- WASHINGTON IA-WHITESIDE IL- 500 AM CDT TUE APR 28 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL ILLINOIS...NORTHWEST ILLINOIS...WEST CENTRAL ILLINOIS...EAST CENTRAL IOWA...NORTHEAST IOWA...SOUTHEAST IOWA AND NORTHEAST MISSOURI. .DAY ONE...TODAY AND TONIGHT SEVERAL AREA RIVERS ARE EXPERIENCING MINOR TO MODERATE FLOODING. SEE THE LATEST FLOOD STATEMENTS FOR UPDATES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY ANOTHER ROUND OF THUNDERSTORMS...POSSIBLY WITH HEAVY RAIN...WILL OCCUR WEDNESDAY NIGHT INTO THURSDAY. THIS NEW RAINFALL IS EXPECTED TO RAISE ALREADY HIGH RIVER LEVELS. MORE THUNDERSTORMS ARE FORECAST FOR FRIDAY. THE STORM PREDICTION CENTER HAS A SLIGHT RISK OF SEVERE STORMS FOR AREAS SOUTH OF INTERSTATE 80. ALTHOUGH NOT AS CLEAR...THERE MAY BE A CHANCE OF THUNDERSTORMS ON SUNDAY. SEVERAL AREA RIVERS ARE EXPERIENCING MINOR TO MODERATE FLOODING. SEE THE LATEST FLOOD STATEMENTS FOR UPDATES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY OR TONIGHT.
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Heavy rains during the last week of April resulted in the Iowa River at Marengo going above the moderate flood stage level of 15.5 feet on April 29th around 2 am. It crested around 17.64 feet around 9 pm April 30. It stayed in moderate flooding through the end of the month.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2009Every state in 2009This day in weather historyWarnings in Iowa, April 2009
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: 164711.