A very strong low pressure system lifted northeast from north central Nebraska into east central South Dakota during the evening of the 9th. The system was very dynamic, being a negatively tilted trough in the mid and upper levels of the atmosphere.
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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 DMX wrote it up.
A very strong low pressure system lifted northeast from north central Nebraska into east central South Dakota during the evening of the 9th. The system was very dynamic, being a negatively tilted trough in the mid and upper levels of the atmosphere. A strong gradient was in place across Iowa, with winds of 75 kts within two thousand feet of the surface. The dry slot lifted across the state and strong winds formed in the subsidence region. An area of showers rotated into the dry slot over the northwest third of the state. The rain resulted in cooling in the low levels through evaporational cooling to help bring the winds down to the surface. In addition a few areas around the rest of the state reported breakthrough winds near high wind category. One location was in Marion County at Pella, where a 59 MPH wind gust was recorded. Another break through area occurred in Polk County in Ankeny, where high winds resulted in minor damage to a house there. The greatest area of high winds was in a band about 40 to 50 miles wide extending from northeast of Denison, northeast into Hancock County. Sustained winds of 30 to 35 MPH were recorded, with gusts of near 60 MPH at several locations. Two semi-tractortrailer trucks were overturned by the winds. One was near Britt, in Hancock County, the other near Thompson in Winnebago County.
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 Des Moines, IA wrote its last area forecast discussion before the first event at Feb 9, 5:25 PM CST, 35 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 525 PM CST MON FEB 9 2009 UPDATED AVIATION DISCUSSION .SHORT TERM.../TONIGHT/ STRONG SHORT WAVE WILL LIFTING RAPIDLY NORTHEAST THROUGH ERN NEBRASKA AND WESTERN IOWA. DESPITE SUBSIDENCE IN THE WAKE OF THE IMPULSE...MAX MOMENTUM TRANSFER OF VERY STRONG WINDS ALOFT TO THE SFC NOT TAKING PLACE IN AREAS WITH SOUTH OR SOUTHEAST WINDS (DESPITE PEAK HEATING) WHICH CAN BE SEEN ON THE 18Z KOMA SOUNDING. BETTER MOMENTUM TRANSFER OCCURRING WHERE THE WIND BECOMES SOUTHWESTERLY WITH A FEW OBSERVATIONS REACHING 50KTS OVER CNTRL KS. EXPECT THE OVERALL POTENTIAL OF THE NON CONVECTIVE GUSTS TO SUBSIDE THE NEXT FEW HOURS AS SUNSET APPROACHES. ANOTHER SHORT WAVE WILL ARRIVE OVER WEST CENTRAL IOWA TOWARDS 00Z. SOME INSTABILITY IS AVAILABLE DURING THIS PERIOD AND EXPECT SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP OVER THE WEST CENTRAL AND LIFT RAPIDLY NORTHEAST INTO NORTH CENTRAL IOWA. DESPITE IMPRESSIVE 0-1KM SRH...ANY STORMS SHOULD BE ELEVATED BY THIS TIME. ANY SEVERE THREAT WOULD BE POTENTIAL FOR 60 MPH WINDS WITH PRECIPITATION PULLING STRONG WINDS DOWN FROM ALOFT THOUGH THIS SHOULD BE ISOLATED AT BEST. CLEARING WILL OCCUR IN THE WAKE OF THIS SECONDARY WAVE WITH TEMPERATURES REMAINING MILD OVERNIGHT IN THE UPPER 30S TO MID 40S WHILE WINDS REMAIN OUT OF THE SOUTHWEST AT 10 TO 20 MPH. .LONG TERM.../TUESDAY-MONDAY/ FIRST ISSUE TUESDAY WILL BE POTENTIAL WIND ADVISORY CRITERIA ACROSS NORTHERN IOWA. FORECAST SOUNDINGS INDICATE 40-50 KTS AT THE TOP OF THE MIXED LAYER DURING THE LATE MORNING THROUGH MID AFTERNOON. NO NEED FOR ANY HEADLINES ATTM GIVEN CURRENT WIND ADVISORY AND MID SHIFT CAN RE-EVALUATE. RESULTING MIXING WILL KEEP TEMPS WELL ABOVE NORMAL AGAIN AND RAISED TEMPS IN THE NORTH WHERE THE SNOW FIELD CONTINUES TO ERODE. ADDITIONAL RAIN OF ANY SIGNIFICANCE THIS WEEK SHOULD BE LIMITED TO THE FAR SE COUNTIES AND WILL LIKELY REDUCE THE CHANCES OF ANY SIGNIFICANT FLOODING ACROSS THE CWA. SEE BELOW FOR ADDITIONAL HYDRO DISCUSSION. ATTENTION THEN TURNS TO THE TUES NITE/WED SYSTEM. OPERATIONAL AND ENSEMBLE GUIDANCE POINT TOWARDS THE MAIN IMPACTS ACROSS THE FAR SE FORECAST AREA. THE GEM IS AN OUTLIER WITH A FARTHER NW SFC LOW TRACK. MORE UNSEASONABLY MOIST AIR WILL BE PULLED NORTH INTO SOUTHERN IOWA WITH PWAT/S AROUND AN INCH...ALONG WITH SOME ELEVATED INSTABILITY. ADDED THUNDER MENTION IN THE CENTERVILLE/OTTUMWA AREAS. STAYED CLOSE TO HPC QPF GUIDANCE...WHICH AMOUNTS TO A FEW TENTHS UP TO A HALF INCH IN DAVIS COUNTY. COOLER TEMPERATURES WILL PREVAIL FOR THE REST OF THE WEEK. WARM READINGS THROUGH TUESDAY WILL TAKE CARE OF MUCH OF THE REMAINING SNOW COVER NORTH SO CURRENT FCST MAY BE A TOUCH TOO COLD ACROSS THAT AREA. MODEL CONSENSUS BREAKS DOWN REGARDING THE LATE WEEK SYSTEM. THE GFS IS RELATIVELY DRY...WHILE THE ECMWF IS STILL INSISTENT IN GENERATING A HEAVY SNOW BAND ACROSS IOWA FRIDAY AND FRIDAY NIGHT. HAVE BUMPED POPS UP A BIT BUT WOULD NOT BE PRUDENT TO COMPLETELY FAVOR THE ECMWF ATTM. ANOTHER SHORT WAVE TROUGH MAY IMPACT THE CWA SUN/SUN NITE. && .AVIATION...10/00Z DRY SLOT OVER THE AREA AT 00Z WITH ALL AREAS VFR EXCEPT SOME RESIDUAL MVFR FOG AT KMCW. ADDITIONAL SHORTWAVE ENERGY PASSING ACROSS ERN NEB WILL SCOOT ACROSS NW IA THIS EVENING AND COMBINED WITH WEAK INSTABILITY...MOSTLY ALOFT...WILL LIKELY DEVELOP A BAND OF SHOWERS AND ISOLATED TSRA WHICH COULD AFFECT KFOD AND KMCW THRU 04Z OR SO. OTHERWISE...VFR CONDITIONS EXPECTED THRU THE TAF PERIOD AND THE WIND IS THE ONLY FORECAST ISSUE. EXPECT WINDS TO REMAIN OVER 15 KTS UNTIL AFT 21Z TUES AND GUSTY...WITH A GRADUAL VEERING TO THE WSW. && .HYDROLOGY... MOST RIVERS ACROSS THE CWA ARE RUNNING ABOVE NORMAL TO NEAR FLOOD STAGE TODAY. THE SOUTH SKUNK AT OSKALOOSA IS THE ONLY POINT CURRENTLY OVER FLOOD STAGE. RAINFALL TODAY WAS MAINLY LIMITED TO 1-2 TENTHS AND WILL NOT ADD TO THE RIVER FLOOD THREAT. ONLY SPOTTY ADDITIONAL AMOUNTS ARE EXPECTED TONIGHT...AND LIGHT TO MODERATE RAIN LATER IN THE WEEK SHOULD BE LIMITED TO THE FAR SE COUNTIES. THIS MEANS THAT ANY FURTHER FLOODING ALONG RIVERS AND STREAMS THIS WEEK WILL LIKELY RESULT FROM SNOW MELT AND/OR ICE JAMS. SPORADIC SNOW COVER REMAINS ACROSS NORTHERN IOWA...AND THIS WILL MOSTLY OR COMPLETELY MELTED WITH THE WARM TEMPS OVERNIGHT INTO TOMORROW. RIVERS ACROSS NORTHERN INTO CENTRAL IOWA SHOULD SEE RISES IN RESPONSE TO THE SNOW MELT THIS WEEK...WITH MINOR FLOODING POSSIBLE AT SOME LOCATIONS. AS THIS WATER MOVES DOWNSTREAM...RENEWED RISES ARE POSSIBLE IN SOUTHERN IOWA. A BIGGER THREAT IS FLOODING DUE TO ICE JAMS. REPORTS FROM THE FIELD TODAY INDICATE SOME MINOR ICE JAMS AND/OR HEAVED ICE ALONG THE RACCOON RIVER AT FLEUR...HIGHWAY 28...AND NEAR VAN METER. THESE AREAS BEAR WATCHING IN THE NEAR FUTURE. THE GREATER THREAT FOR ICE JAMS APPEARS TO BE NORTH OF HIGHWAY 30...WHERE SNOW MELT THROUGH TUESDAY MAY RESULT IN RISES THAT WOULD BE SUFFICIENT TO BREAK UP EXISTING ICE. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...DONAVON LONG TERM...KINNEY AVIATION...MOYER HYDROLOGY...ZOGG/KINNEY
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 436 PM CST MON FEB 9 2009 IAZ044>050-057>062-070>075-081>086-092>097-101200- CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE- DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION- MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD- DECATUR-WAYNE-APPANOOSE-DAVIS- 436 PM CST MON FEB 9 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND SOUTHERN IOWA...ALONG AND SOUTH OF HIGHWAY 30. THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT A STRONG SOUTH WIND WILL CONTINUE THIS EVENING. EXPECT SUSTAINED SPEEDS OF 25 TO 35 MPH...WITH GUSTS AROUND 45 MPH THROUGH 9 PM. A WIND ADVISORY IS IN EFFECT FOR THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. MINOR FLOODING IS CONTINUING ALONG THE SOUTH SKUNK RIVER AT OSKALOOSA...WHERE A FLOOD WARNING CONTINUES. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH TUESDAY. SOME RISES ON AREA STREAMS AND RIVERS WILL CONTINUE...AS A RESULT OF SNOW MELT TO THE NORTH...AND MINOR FLOODING AT OTHER POINTS IS POSSIBLE THROUGH THE WEEK. FLOODING FROM ICE JAMS WILL ALSO BE POSSIBLE THROUGH LATE WEEK. LATE IN THE WEEK A CHANCE FOR SNOW WILL RETURN TO IOWA. SOME LIGHT TO MODERATE SNOWFALL IS POSSIBLE FRIDAY AND FRIDAY NIGHT...ESPECIALLY ACROSS FAR SOUTHERN IOWA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT. IAZ004>007-015>017-023>028-033>039-101200- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN- WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK- 436 PM CST MON FEB 9 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN IOWA...NORTH OF HIGHWAY 30. .DAY ONE...TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH MID EVENING. AN ISOLATED SEVERE STORM IS POSSIBLE WITH A WIND GUST TO 60 MPH. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH TUESDAY. SOME RISES ON AREA STREAMS AND RIVERS WILL CONTINUE...AS A RESULT OF SNOW MELT...AND MINOR FLOODING IS POSSIBLE THROUGH THE WEEK AT SOME POINTS. FLOODING FROM ICE JAMS WILL ALSO BE POSSIBLE THROUGH LATE WEEK. LATE IN THE WEEK A CHANCE FOR SNOW WILL RETURN TO IOWA. SOME LIGHT TO MODERATE SNOWFALL IS POSSIBLE FRIDAY AND FRIDAY NIGHT...ALTHOUGH THE CHANCE FOR SNOW WILL BE HIGHER TO THE SOUTH. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED ON AN ISOLATED BASIS THROUGH MID EVENING. KINNEY
The national radar mosaic for the moment the first event began.
12 high wind. Local standard time, as filed.
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, February 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: 144872, 144873, 144874, 144875, 144876, 144877, 144878, 144879, 144880, 144881, 144882, 145804.