A very humid and unstable airmass was in place over Iowa during the evening of the 11th into the morning of the 12th. A strong push if moisture pushed precipitable water values to over 2 inches over southern Iowa by evening.
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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 humid and unstable airmass was in place over Iowa during the evening of the 11th into the morning of the 12th. A strong push if moisture pushed precipitable water values to over 2 inches over southern Iowa by evening. Surface dew point temperatures rose to the mid 70s to around 80. The airmass was quite unstable with 3000 to 4000 J/kg of CAPE available and a lifted index around -8 C. There was little shear present however and steering winds were quite light. Thunderstorms formed initially along an east-northeast to west-northwest outflow boundary left by convection the previous morning. This boundary was reinforced as a weak cold front and dropped southeast into Iowa. Thunderstorms developed along this boundary and moved very slowly, dumping heavy rainfall of 1 to 3 inches on top of already saturated ground. Spotty heavier reports were received with unofficial totals of nearly 4 inches southeast of Des Moines in the Knoxville area. The heavy rainfall resulted in flash flooding. Since the rain was unable to percolate into the soil, ditches filled with water and numerous county roads were flooded. Some state highways were flooded as well with water of 1 to 2 feet in depth flowing over the road. Highway 92 in Mahaska County, and Highway 415 in Polk County were flooded for example. There was little severe weather associated with this thunderstorm activity. A 58 MPH wind gust was reported by an RWIS site near Fort Dodge however. Lightning struck a business in Runnells. Bakeris Roofing was struck and set on fire. The fire took 8 fire departments two hours to put out and the business was destroyed.
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 Jun 12, 2:29 AM CST, 31 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 329 AM CDT SAT JUN 12 2010 .SHORT TERM /TODAY/... FOR THE THIRD MORNING IN A ROW...A LARGE CONVECTIVE SYSTEM WILL MOVE FROM NEBRASKA IN IOWA PRODUCING VERY HEAVY RAINFALL. IN ADDITION...A QUASI STATIONARY BOUNDARY NEAR THE HIGHWAY 34 CORRIDOR WILL BE A FOCUS FOR CONVECTION DURING THE MORNING. SHEAR IS RELATIVELY WEAK ACRS THE STATE WITH 500MB WINDS OF 5 TO 10 KTS...SO SEVERE WEATHER APPEARS RELATIVELY MINIMAL. HOWEVER...AMPLE MOISTURE IS IN PLACE ALONG WITH DEEP WARM CLOUD LAYERS AND WARM PCPN PROCESSES LEADING TO EFFICIENT RAIN PRODUCERS. ONGOING FFA WILL BE KEPT IN TACT AS LARGE CONVECTIVE COMPLEX MOVES INTO THE STATE. GRIDS HAVE LIKELY TO CATEGORICAL POPS THROUGH THE MORNING FOR THIS ONGOING CONVECTION WITH SCATTERED WORDING THIS AFTERNOON AS EVOLUTION OF THE SYSTEM AND SUBSEQUENT CONVECTION REMAINS MURKY. TEMPS ALSO PROBLEMATIC GIVEN CLOUDS AND RAINFALL DURING THE DAY SO WL STICK CLOSE TO GUIDANCE. .LONG TERM /TONIGHT THROUGH FRIDAY/... MODELS OF LITTLE HELP FOR THE NEXT FEW DAYS AS MESOSCALE DOMINATES CURRENT WX REGIME. SUBJECTIVE SFC ANALYSIS AT 06Z SHOWS BOUNDARY FROM NEAR KOMA TO JUST SOUTH OF KDSM TO NEAR KDBQ. WEAK SFC LOWS CONTINUE TO TRACK ALONG IT. VERY WARM AND HUMID ALONG THE BOUNDARY AND MUCH COOLER AND DRIER NORTH. A SECONDARY COOL FRONT LIES ALONG THE MN DAKOTAS BORDER AND NOW CATCHING UP WITH THE TROUGH THAT LIES ACROSS THE PLAINS NOW. UPPER LEVEL PATTERN SUGGESTS THAT THREAT FOR MODERATE TO HEAVY RAINFALL WILL CONTINUE IN PART THROUGH MID TO END OF WEEK...WITH DETAILS OF HOW MESOSCALE MODULATES THE FLOW A DAILY GRIND FOR NOW. H700 SHOWS 3 DISTINCT WAVES WHICH WILL AFFECT THE REGION AGAIN TNT THROUGH MONDAY. MODELS DO HINT AT COOLER AND DRIER AIR MASS TO ARRIVE ON TUESDAY FOR ABOUT 24 TO 30 HOURS BEFORE ANOTHER WAVE PULLS SOUTHERN AIR MASS AND POTENTIAL MCS BACK ACROSS THE AREA AGAIN FOR WED NIGHT AND THURSDAY. WITH SUBTROPICAL HIGH ANCHORED OVER THE SOUTHEAST FOR MUCH OF THE WEEK...LITTLE CHANGE IN PRECIP POTENTIAL EXPECTED. GEM IS A BIT MORE AGGRESSIVE WITH TAKING THE LATE WEEK SYSTEM FARTHER NORTH. IN THE SHORTER TERM...WITH H850 MOISTURE LEVELS OF +20C DEWPOINTS FROM CENTRAL KS SOUTH TO WESTERN TX AND LARGE AREA OF +15C DEW POINTS COVERING MOST OF THE EAST US... A LOT OF WET WX TO COME. GENERAL FEELING IS THAT ONCE THIS DUAL MCS WORKS ITS WAY EAST BY TONIGHT...THE SFC BOUNDARY WILL GRADUALLY SHIFT SOUTH FOR SUNDAY AND INTO MONDAY...KEEPING HIGHER POPS ACROSS THE SOUTH AT THAT TIME. ANOTHER WAVE APPROACHES ON MONDAY NIGHT AND EARLY TUESDAY AND HAVE BUMPED POP UP ONCE AGAIN. TEMPS WARM THE NEXT 2 DAYS AND THEN HAVE LOWERED HIGHS A BIT MOVING FORWARD. && .AVIATION... 12/06Z...LITTLE CHANGE FROM PREVIOUS 18Z AND 00Z THINKING. EXPECT CONVECTIVE COMPLEX OVER NEBRASKA TO CONTINUE MOVING SLOWLY EASTWARD INTO IA WITH POSSIBLY ADDITIONAL DEVELOPMENT FARTHER EAST INTO IA BEFORE IT GETS HERE. THUS HAVE HIGH CONFIDENCE THAT CONVECTION AND THUNDER WILL AFFECT SITES LATE TONIGHT AND INTO SAT MORNING...BUT LITTLE CONFIDENCE REGARDING TIMING AT ANY PARTICULAR LOCATION. THUS WILL STAY WITH VICINITY WORDING UNTIL TIMING BECOMES CLEARER. SIMILAR THINKING WITH VFR VS MVFR. CIGS WILL LIKELY DROP TO MVFR OR LOWER WITH STORM OCCURRENCES...BUT PREDICTABILITY TOO LOW TO INCLUDE AT THIS TIME. WINDS WILL BE DIFFICULT TO PIN DOWN AS WELL WITH MEANDERING FRONT EXTENDED SW-NE ACROSS IA AT 06Z AND EXPECTED TO MOVE LITTLE. && .DMX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH EXTENDED THROUGH 21Z ADAMS-ADAIR-AUDUBON-CALHOUN- CARROLL-CASS-CRAWFORD-EMMET-GREENE-GUTHRIE-HUMBOLDT-KOSSUTH- PALO ALTO-POCAHONTAS-RINGGOLD-SAC-TAYLOR-UNION-WEBSTER && SHORT TERM...COGIL LONG TERM...REV AVIATION...SMALL
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 406 PM CDT FRI JUN 11 2010 IAZ004-005-015-023-024-033>035-044>046-057-058-070-071-122115- EMMET-KOSSUTH-PALO ALTO-POCAHONTAS-HUMBOLDT-SAC-CALHOUN-WEBSTER- CRAWFORD-CARROLL-GREENE-AUDUBON-GUTHRIE-CASS-ADAIR- 406 PM CDT FRI JUN 11 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE THIS EVENING. A LARGER AREA OF THUNDERSTORMS AND HEAVY RAIN IS EXPECTED TO MOVE THROUGH LATE TONIGHT. DAMAGING WINDS AND SMALL HAIL ARE THE MAIN THREATS. RAINFALL RATES IN EXCESS OF ONE INCH PER HOUR COULD LEAD TO FLASH FLOODING. A FLASH FLOOD WATCH IS IN EFFECT FOR THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORMS AND HEAVY RAIN ARE LIKELY EARLY SATURDAY. A FLASH FLOOD WATCH REMAINS IN EFFECT SATURDAY MORNING. THE THREAT OF DAMAGING WINDS DURING THIS TIME IS LOW. THUNDERSTORM CHANCES CONTINUE INTERMITTENTLY THROUGHOUT THE WEEKEND AND INTO NEXT WEEK. THERE THREAT OF SEVERE WEATHER APPEARS FAIRLY MINIMAL AT THIS TIME FOR THE WEEKEND...AND IT IS TOO EARLY TO DETERMINE THE CHANCE OF SEVERE WEATHER FOR NEXT WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TONIGHT OR SATURDAY. IAZ006-007-016-017-025>028-036>039-047>050-059>062-072>075-081>086- 092>097-122115- WINNEBAGO-WORTH-HANCOCK-CERRO GORDO-WRIGHT-FRANKLIN-BUTLER-BREMER- HAMILTON-HARDIN-GRUNDY-BLACK HAWK-BOONE-STORY-MARSHALL-TAMA-DALLAS- POLK-JASPER-POWESHIEK-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION- CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE- DAVIS- 406 PM CDT FRI JUN 11 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE THIS EVENING. A LARGER AREA OF THUNDERSTORMS AND HEAVY RAIN IS EXPECTED TO MOVE INTO THE REGION LATE TONIGHT. DAMAGING WINDS AND SMALL HAIL ARE THE MAIN THREATS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORMS AND HEAVY RAIN ARE LIKELY EARLY SATURDAY. THE THREAT OF DAMAGING WINDS DURING THIS TIME IS LOW...BUT LOCALLY HEAVY RAIN COULD LEAD TO FLOODING. THUNDERSTORM CHANCES CONTINUE INTERMITTENTLY THROUGHOUT THE WEEKEND AND INTO NEXT WEEK. THERE THREAT OF SEVERE WEATHER APPEARS FAIRLY MINIMAL AT THIS TIME FOR THE WEEKEND...AND IT IS TOO EARLY TO DETERMINE THE CHANCE OF SEVERE WEATHER FOR NEXT WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TONIGHT OR SATURDAY. MOYER
The Des Moines radar (KDMX), 53 km away, was scanning. The volume nearest the first event began at 08:58 UTC.
8 flash flood, 1 thunderstorm wind, 1 lightning, 1 heavy rain, 1 flood. Local standard time, as filed.
Sheriff reports water 1 foot deep at an intersection in Pleasantville at 300 AM CST.
Southbound lanes of Highway 415 closed due to water running over the road.
Water from the Muchakinock Creek was flowing over Highway 92 and the highway was closed due to flowing water.
A foot of water was flowing over 110th and Beardsley in northern Marion County.
At least a foot of water was flowing over the road at the intersection of Highland and 245th Street, and also at Highland and 235th Street.
Water flowing over the road about 6 inches deep along 4th Ave east between South 3rd and South 1st St.
Estimated 4-5 inches of rainfall.
Two inches of water was flowing across a gravel road from farm field to farm field near the intersection of 310th and Y Ave along the Boone and Story County line.
Coal Creek was rising and had closed paved Highway G40. Water from the creek was also over Highway 92, but traffic was still moving. Numerous rural gravel roads in western Marion County were under water.
Four Mile Creek was flowing over Williams St. Williams St. was closed between east University and Mattern Ave.
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, June 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: 224584, 224581, 224583, 224585, 224586, 224587, 224613, 229482, 224873, 224582, 224588, 224614.