The very wet weather pattern of June and July continued into the first two weeks of August. Central Iowa was hardest hit by rainfall with three consecutive nights of torrential rains on the 8th, 9th and 10th.
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 DMX wrote it up.
The very wet weather pattern of June and July continued into the first two weeks of August. Central Iowa was hardest hit by rainfall with three consecutive nights of torrential rains on the 8th, 9th and 10th. Ankeny recorded 9.86 inches of rain over these three nights while Ames had 9.61 inches. Record flooding impacted much of Story, Polk, Jasper and Mahaska counties. Iowa received a much needed break from the heavy rainfall for most of the second half of the month with a statewide average of only 0.91 inches between 14th and the morning of the 31st. Moderate to heavy rain fell on the night of the 31st into early September 1st over the southeast two-thirds of Iowa with the Ames Airport recording 4.13 inches. Most official reporting points record rainfall once daily at about 7 a.m. CDT, thus in many cases the rain of late August 31 will go into the record books for September 1. Monthly rain totals for August (through 7 a.m. August 31) varied from only 1.03 inches at Guttenberg to 16.07 inches at Urbandale. August rainfall was well below normal over much of north central, northeast and far southwest Iowa. The flooding was major along the Skunk and parts of the lower Des Moines River basin. Following the flash flooding of the 10th and 11th, major river flooding continued. Significant crop losses occurred because of the high water flooding fields for several days. Major damage was done along the Skunk Basin from Ames, through Colfax. Water from the South Skunk River completely covered portions of US Highway 30 near Ames and Interstate 35 just south of Ames. The water system was knocked out in Ames, and threatened in Colfax. Highway 117 just south of Interstate 80 was closed and barricaded due to water over the road from the South Skunk near Colfax. Significant damage occurred along the Des Moines River in Eddyville as well as Ottumwa with the river in major flood for several days.
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 Aug 9, 3:38 AM CST, 1 hour 10 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 438 AM CDT MON AUG 9 2010 .UPDATE AVIATION DISCUSSION 09/12Z... .SHORT TERM /TODAY/... AT LEAST A COUPLE OF SFC BOUNDARIES AND THIS VERY HUMID AIRMASS WILL MEAN AN ACTIVE DAY NO DOUBT. CURRENT MCS THAT JUST WILL NOT QUIT...FEEDING OFF LOW LEVEL JET AND UPPER LEVEL WAVE SHOULD GRADUALLY DIMINISH OR PUSH OFF TO THE EAST. FLASH FLOOD THREAT CONTINUES AND HAVE EXPANDED THE WATCH FARTHER EAST THROUGH MID MORNING. MULTIPLE OUTFLOW BOUNDARIES AND THE MAIN SYNOPTIC BOUNDARY LINGERING THROUGH CENTRAL IOWA WILL BE THE FOCUS FOR ADDITIONAL DEVELOPMENT ESPECIALLY THIS AFTERNOON AS AIRMASS BECOMES VERY UNSTABLE AGAIN. THERE IS THE RISK FOR SEVERE WEATHER...WITH REALLY ANYTHING POSSIBLE...EVEN A TORNADO THREAT GIVEN BOUNDARY INTERACTIONS. EXCESSIVE HEAT WARNING STILL IN EFFECT FOR FAR SOUTHWESTERN COUNTIES AND ALSO ADDED A HEAT ADVISORY FOR SOUTHERN COUNTIES. AM SOMEWHAT CONCERNED ABOUT THE CLOUD COVER EARLY IN THE DAY POSSIBLY LIMITING THE WARMUP...BUT ODDS ARE THE FARTHER SOUTH AND WEST YOU ARE...THE MORE LIKLEY TO SEE MORE SUNSHINE. DEWPOINTS WILL ONCE AGAIN REBOUND INTO THE UPPER 70S TO LOWER 80S...MAKING FOR THE OPPRESSIVE CONDITIONS. .LONG TERM /TONIGHT THROUGH SUNDAY/... EXPECT MORE OF THE SAME THROUGH AT LEAST WEDNESDAY. MAINLY NIGHT AND MORNING THUNDERSTORM COMPLEXES RIDING UP AND OVER UPPER LEVEL RIDGE AXIS. THE MOST LIKELY TRACK WILL ALLOW FOR THESE STORMS TO AFFECT MAINLY THE NORTH AND EAST HALVES OF CENTRAL IOWA. SO FARTHER SOUTHWEST...THE OPPRESSIVE HEAT WILL LIKELY CONTINUE. ADDITIONAL HEAT WARNINGS OR ADVISORIES WILL LIKELY BE ISSUED LATER TODAY FOR ADDITIONAL DAYS THIS WEEK. THE ONLY LIMITING FACTOR WILL BE POTENTIAL FOR LINGERING MORNING RAIN OR DEBRIS CLOUDS THAT KEEP US COOLER THAN PREDICTED. RIDGE AMPLIFIES OVER THE REGION THURSDAY ENOUGH TO PROBABLY KEEP US DRY...BUT A MORE SIGNIFICANT UPPER LEVEL TROUGH LOOKS POISED TO SWING THROUGH OUR REGION FRIDAY NIGHT...WITH FORCING FOR MORE SHOWERS/STORMS ARRIVING AS EARLY AS THURSDAY NIGHT. && .AVIATION...09/12Z STORMS WHICH PUSHED THROUGH CENTRAL IOWA OVER NIGHT WILL CONTINUE TO PUSH EASTWARD...AFFECTING KALO AND KOTM EARLY IN THE PERIOD. CEILINGS WILL REMAIN VFR THROUGH THE EARLY AFTERNOON...HOWEVER ANOTHER ROUND OF STORMS IS POSSIBLE AFTER 18Z AS INSTABILITY REDEVELOPS ACROSS THE REGION. HAVE PUSHED TIMING BACK A BIT FROM PREVIOUS FORECAST TO ALLOW THE ATMOSPHERE TO RECOVER AND DUE TO UNCERTAINTY. OVERNIGHT CONVECTION IS ONCE AGAIN POSSIBLE...AND HAVE TRENDED TOWARDS THIS WITH THE TAFS. HAVE LEFT VSBYS LOWER THROUGH 12Z ALLOWING FOR FOG DEVELOPMENT. && .DMX WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR ADAIR- ADAMS-AUDUBON-CARROLL-CASS-CRAWFORD-GUTHRIE-RINGGOLD-SAC-TAYLOR- UNION. FLASH FLOOD WATCH UNTIL 9 AM CDT THIS MORNING FOR BOONE-CALHOUN- HAMILTON-JASPER-MAHASKA-MARION-MARSHALL-POCAHONTAS-POLK- POWESHIEK-STORY-TAMA-WARREN-WEBSTER. HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM CDT THIS EVENING FOR APPANOOSE-CLARKE-DAVIS-DECATUR-LUCAS-MADISON-MONROE-WAPELLO- WAYNE. && SHORT TERM...MOYER LONG TERM...MOYER AVIATION...AW
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 836 PM CDT SUN AUG 8 2010 IAZ033-044-045-057-058-070-071-092215- SAC-CRAWFORD-CARROLL-AUDUBON-GUTHRIE-CASS-ADAIR- 836 PM CDT SUN AUG 8 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT STORMS MAY BE SEVERE WITH SEVERE WINDS TO 70 MPH THE PRIMARY THREAT. AN ISOLATED TORNADO IS ALSO POSSIBLE. HEAVY RAIN IS ALSO POSSIBLE WITH 1 TO 2 INCHES ON AVERAGE AND LOCALLY HIGHER TOTALS WHICH MAY APPROACH 5 INCHES AT SOME LOCATIONS. EXCESSIVE HIGH INDEX TEMPERATURES OF 110 TO 115 DEGREES WILL NOT FALL BELOW THE UPPER 70S TONIGHT. AN EXCESSIVE HEAT WARNING IS IN EFFECT FOR TONIGHT. MONDAY. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR TONIGHT INTO EARLY MONDAY. PLEASE SEE PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS CHANCE OF THUNDERSTORMS THROUGH THE BALANCE OF THE WEEK...MAINLY AT NIGHT. ISOLATED SEVERE WEATHER AND LOCALLY HEAVY RAIN WILL BE POSSIBLE...ESPECIALLY THROUGH MID MORNING MONDAY. EXCESSIVE HEAT INDEX TEMPERATURES OF 110 TO 115 DEGREES ARE POSSIBLE MONDAY. THE CHANCE OF HIGH HEAT INDEX TEMPERATURES OF 100 TO 110 THROUGH MIDWEEK. AN EXCESSIVE HEAT WARNING IS IN EFFECT FOR TONIGHT. MONDAY. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. A FLASH FLOOD WATCH HAS BEEN ISSUED INTO EARLY MONDAY. PLEASE SEE PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE FROM TIME TO TIME. IAZ081-082-092-093-092215- ADAMS-UNION-TAYLOR-RINGGOLD- 836 PM CDT SUN AUG 8 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT THERE IS A CHANCE OF THUNDERSTORMS LATE TONIGHT. A FEW STORMS MAY BE SEVERE WITH SEVERE WINDS THE PRIMARY THREAT. ISOLATED HEAVY RAIN IS ALSO POSSIBLE. EXCESSIVE HIGH INDEX TEMPERATURES OF 110 TO 115 DEGREES WILL NOT FALL BELOW THE UPPER 70S TONIGHT. AN EXCESSIVE HEAT WARNING IS IN EFFECT FOR TONIGHT. MONDAY. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THROUGH THE BALANCE OF THE WEEK...MAINLY AT NIGHT. ISOLATED SEVERE WEATHER AND LOCALLY HEAVY RAIN WILL BE POSSIBLE. EXCESSIVE HEAT INDEX TEMPERATURES OF 110 TO 115 DEGREES ARE POSSIBLE MONDAY. THE CHANCE OF HIGH HEAT INDEX TEMPERATURES OF 100 TO 110 THROUGH MIDWEEK. AN EXCESSIVE HEAT WARNING IS IN EFFECT FOR TONIGHT. MONDAY. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE FROM TIME TO TIME. IAZ023-034>036-046>049-059>061-072-073-092215- POCAHONTAS-CALHOUN-WEBSTER-HAMILTON-GREENE-BOONE-STORY-MARSHALL- DALLAS-POLK-JASPER-MADISON-WARREN- 836 PM CDT SUN AUG 8 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT THUNDERSTORMS WILL MOVE INTO THE AREA TONIGHT. HEAVY RAINFALL IS LIKELY WITH THE STORMS WITH 1 TO 2 INCHES ON AVERAGE AND LOCALLY HIGHER TOTALS WHICH MAY APPROACH 5 INCHES AT SOME LOCATIONS. . A FEW STORMS MAY BE SEVERE WITH DAMAGING WINDS TO 70 MPH OR GREATER THE PRIMARY THREAT. AN ISOLATED TORNADO IS ALSO POSSIBLE. HEAT INDICES WILL FALL BELOW 100 BY LATE EVENING. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR TONIGHT INTO EARLY MONDAY. PLEASE SEE PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A CHANCE OF THUNDERSTORMS THROUGH THE BALANCE OF THE WEEK...MAINLY AT NIGHT. ISOLATED SEVERE WEATHER AND LOCALLY HEAVY RAIN WILL BE POSSIBLE...ESPECIALLY THROUGH MID MORNING MONDAY. HEAT INDEX TEMPERATURES OF 100 TO 105 DEGREES ARE POSSIBLE ON MONDAY. THE CHANCE OF HIGH HEAT INDEX TEMPERATURES WILL CONTINUE THROUGH MID WEEK. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR INTO EARLY MONDAY. PLEASE SEE PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS FROM TIME TO TIME. IAZ004>007-015>017-024>028-037>039-050-062-074-075-083>086-094>097- 092215- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-HUMBOLDT- WRIGHT-FRANKLIN-BUTLER-BREMER-HARDIN-GRUNDY-BLACK HAWK-TAMA- POWESHIEK-MARION-MAHASKA-CLARKE-LUCAS-MONROE-WAPELLO-DECATUR-WAYNE- APPANOOSE-DAVIS- 836 PM CDT SUN AUG 8 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT THUNDERSTORMS WILL BE LIKELY TONIGHT. A FEW STORMS MAY BE SEVERE WITH DAMAGING WINDS TO 70 MPH OR GREATER THE PRIMARY THREAT...LARGE HAIL A SECONDARY THREAT. AN ISOLATED TORNADO IS ALSO POSSIBLE SOUTH OF HIGHWAY 20. HEAVY RAIN IS ALSO POSSIBLE. HEAT INDEX TEMPERATURES WILL FALL TO THE UPPER 90S BY MID TO LATE EVENING. RIVER FLOOD WARNINGS ARE IN EFFECT FOR PARTS OF THE AREA. PLEASE SEE PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A CHANCE OF THUNDERSTORMS THROUGH THE BALANCE OF THE WEEK...MAINLY AT NIGHT. ISOLATED SEVERE WEATHER AND LOCALLY HEAVY RAIN WILL BE POSSIBLE. HEAT INDEX VALUE OF 100 TO 105 ARE POSSIBLE THROUGH MID WEEK. RIVER FLOOD WARNINGS ARE IN EFFECT FOR PARTS OF THE AREA. PLEASE SEE PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE THIS EVENING NORTH OF U.S. HIGHWAY 20...AND FROM TIME TO TIME THROUGH THE WEEK. REV
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
449 AM CDT MON AUG 09 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0442 AM FLASH FLOOD DES MOINES 41.58N 93.62W
08/09/2010 POLK IA EMERGENCY MNGR
POLK COUNTY REPORTS FLASH FLOODING AT 4300 BLOCK OF
FAIRVIEW NEAR DEAN AVENUE. FLOOD WATERS WASHED AWAY
RAILROAD TRACKS CAUSING A TRAIN DERAILMENT.
&&
RVACHALEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
452 AM CDT MON AUG 09 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0432 AM HEAVY RAIN 6 ENE STORY CITY 42.22N 93.49W
08/09/2010 M2.60 INCH HAMILTON IA TRAINED SPOTTER
OVERNIGHT RAINFALL TOTAL.
&&
AWPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
503 AM CDT MON AUG 09 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 AM HEAVY RAIN 3 W NEWTON AIRPORT 41.68N 93.08W
08/09/2010 M4.05 INCH JASPER IA TRAINED SPOTTER
RAINFALL SINCE 11 PM LAST NIGHT.
&&
BMOYERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
510 AM CDT MON AUG 09 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0503 AM FLASH FLOOD BOONE 42.05N 93.88W
08/09/2010 BOONE IA LAW ENFORCEMENT
BOONE COUNTY LAW REPORTS NUMEROUS ROADS FLOODED IN TOWN
AS WELL AS FLOODING ALONG OLD HIGHWAY 30 AND HIGHWAYS 17.
&&
RVACHALEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
521 AM CDT MON AUG 09 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0505 AM HEAVY RAIN 1 NNE NEVADA 42.03N 93.45W
08/09/2010 M3.80 INCH STORY IA TRAINED SPOTTER
RAINFALL MEASURED SINCE AROUND MIDNIGHT.
0505 AM HEAVY RAIN NW GRIMES 41.66N 93.79W
08/09/2010 M3.00 INCH POLK IA COCORAHS
RAINFALL FROM OVERNIGHT STORMS.
&&
BMOYERPRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE DES MOINES IA
523 AM CDT MON AUG 09 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0458 AM HEAVY RAIN 3 W NEWTON AIRPORT 41.68N 93.08W
08/09/2010 M4.05 INCH JASPER IA TRAINED SPOTTER
RAINFALL SINCE 11 PM LAST NIGHT.
&&
BMOYERThe national radar mosaic for the moment the first event began.
17 flood. Local standard time, as filed.
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, August 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: 248970, 248967, 248969, 248965, 248961, 248954, 248972, 248971, 248953, 248956, 248968, 248958, 248948, 248973, 248974, 248952, 248962.