Iowa, 2010

Flash Flooding and Flood in Iowa, August 8 to 9, 2010

August 8 to 9, 2010 · NWS DMX · 71 events in 26 counties and zones

A very unstable airmass was in place over Iowa. Afternoon temperatures warmed into the upper 80s to mid 90s, with dewpoint readings in the upper 70s to low 80s.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
$3.3 million
Crop damage
$65,000
Events
71

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.

What happened

The episode as NWS DMX wrote it up.

A very unstable airmass was in place over Iowa. Afternoon temperatures warmed into the upper 80s to mid 90s, with dewpoint readings in the upper 70s to low 80s. A weak boundary extended out of eastern Nebraska across northern Iowa. This boundary helped to focus moisture. At the same time, a negatively tilted shortwave lifted northeast out of the Rockies into Nebraska during the afternoon and early evening. The lifted index fell to -10 to -14 C by evening with CAPE rising to 5000-7000 J/kg in the very moist airmass. The freezing level was very high, between 16,000 and 17,000 feet. As a result, there was little in the way of hail. The downdraft CAPE was quite high, 800 to 1400 J/kg. Thunderstorms formed in northeast Nebraska. They rapidly formed into an upscale MCS, and eventually a full-fledged MCC. Precipitable water values were extremely high, in the 2.5 to 2.75 inch range. The primary mode of severe weather with the system was in the form of high wind. Wind gusts of 60 to 70 MPH caused sporadic damage across western into central Iowa with tree damage, as well as damage to outbuildings. The storms produced one funnel cloud in Carroll County. The high precipitable water values led to very heavy rainfall with widespread flash flooding. A swath of 2 to 5 inch rainfall extended from west central, through central, into parts of southeast Iowa. There were numerous reports of a foot or more of flowing water over streets. Following the flash flooding, water remained standing on many roads due to the soils across the state being nearly saturated. This resulted in some road closures. The Des Moines metropolitan area was hard hit as 3 to 5 inches of rain fell in 4 hours or less. This caused extensive flooding in the city. Some evacuations took place. One was at a trailer court along Four Mile Creek on the east side of Des Moines. Numerous roads were closed on the west side as well as Walnut Creek jumped its banks. In fact, the creek set an all-time record high stage. Fast rising waters of North Walnut Creek flooded four basement apartment units in Clive with water rescues taking place. Lightning struck a house in Adel, setting it on fire. The family was asleep at the time and were rescued by the fire department after the house had been on fire for 45 minutes. Damage to the house was around $1,000,000 as it was a total loss, burned to the ground. In Black Hawk County, lightning struck the water treatment plant in Cedar Falls. Power was knocked out, resulting in the discharge of 750,000 gallons of sewage into the Cedar River. Lightning struck the historical depot in Carroll, now the Chamber of Commerce, and caused minor damage to the roof. It also knocked out telephone service to 3 adjacent buildings.

What forecasters said that day

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 8, 5:14 PM CST, 1 hour 51 minutes earlier.

Area forecast discussion, Aug 8, 5:14 PM CST, 1 hour 51 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
614 PM CDT SUN AUG 8 2010

.UPDATE AVIATION DISCUSSION 09/00Z...

.SHORT TERM /TONIGHT/...
MOISTURE TRANSPORT INTO THE AREA WILL PUSH PWAT VALUES WELL ABOVE
NORMAL AND INTO RECORD TERRITORY.  NAM PRINTED OUT A 3.23 PWAT IN
SWRN IA TNGT...THOUGH TOO HIGH DO FEEL THE 2.5 RANGE IS LKLY.
COMBINATION OF SEVERAL SFC BOUNDARIES WILL AID IN THE INIT DVLPMT OF
THE TSRA.  FIRST FOCUS...AND POTENTIALLY SVR...WILL BE OVR NRN IA
WHERE BNDRY IS PRESENT EAST OF SFC LOW SW OF KSUX.  WEAK FLO ALF AND
SWD DRIFT PRESENT IN CORFIDI VECTORS WILL ALLOW MCS TO SINK WITH
POTENTIAL FOR VERY HEAVY RAINFALL TNGT.  MDLS HAVE BEEN ON TRACK
WITH THIS AND THOUGH BULLSEYE CONTINUALLY SHFTS...IDEA OF MAX PCPN
OF 5 OR MORE INCHES IN SOME AREA HAS BEEN ADVTZD.  WENT WITH A FFA
FOR PARTS OF THE CWA TNGT INTO EARY MON FOR THE FAVORED AREA.

.LONG TERM /MONDAY THROUGH SUNDAY/...
ACTIVE/HOT/HUMID PATTERN TO CONTINUE THROUGH MUCH OF THE WEEK.
BOUNDARY STALLED OUT ACROSS THE CWA MONDAY...WITH CONTINUED PUSH OF
WEAK SHORTWAVES THROUGH THE CWA ATOP THE CENTRAL US UPPER RIDGE. MAY
SEE SOME LINGERING ACTIVITY/CLOUDS ACROSS THE CWA IN THE MORNING.
THIS SHOULD HELP KEEP TEMPS AT BAY SOMEWHAT WHICH WOULD LEAD TO
MAINLY ADVISORY CRITERIA HEAT INDICES BY MONDAY AFTERNOON VERSUS
WARNING CRITERIA. WILL HOWEVER KEEP THE WARNING GOING AT THIS TIME
FOR THE SOUTHWESTERN CWA...UNTIL MIDNIGHT SHIFT HAS A BETTER IDEA TO
ASSESS THE SITUATION. OTHERWISE...BOUNDARY TO PUSH FURTHER NORTH
ACROSS THE CWA TUESDAY INTO TUESDAY NIGHT...WITH MUCH OF THE
SOUTHERN CWA EXPECTED TO BE CAPPED. THEREFORE WENT WITH HIGHER POPS
ACROSS NORTHERN CWA TUESDAY AFTERNOON/NIGHT. COOL FRONT TO DROP
THROUGH THE CWA WEDNESDAY...WITH MORE CHANCES FOR TSRA. HOWEVER AS
FRONT MOVES THROUGH HIGH PRESSURE TO BUILD INTO THE AREA WEDNESDAY
NIGHT/THURSDAY...SO EXPECT A BRIEF RESPITE FROM THE PRECIPITATION
CHANCES. OTHERWISE HIGH PRESSURE PUSHES OFF TO THE EAST INTO
THURSDAY NIGHT/FRIDAY WITH A WARM FRONT MOVING NORTH. THIS WILL
ALLOW FOR ADDITIONAL CHANCES OF PRECIP/HOT AND HUMID CONDITIONS
AGAIN. STRONGER COLD FRONT TO THEN DROP THROUGH THE CWA SATURDAY
NIGHT...WHICH SHOULD ALLOW FOR A PRETTY DECENT COOL DOWN AS H85
TEMPS DROP FROM THE MID 20S CELSIUS TO THE MID TEENS...AND MUCH OF
THE HUMIDITY WILL PUSH SOUTH OF THE REGION AS WELL.

&&

.AVIATION...09/00Z
MCS OVER NEBRASKA STILL MOVING EAST ATTM...BUT A TURN TO THE SOUTH
OR SOUTHEAST IS ANTICIPATED OVER THE NEXT SEVERAL HOURS. EXTREME
INSTABILITY IN PLACE ACROSS MOST OF THE REGION THOUGH H700 TEMPS NOW
UP TO ABOUT +13C WHICH IS MUTING MOST OF THE CURRENT DEVELOPMENT
OVER IA. AS WEAK WAVE APPROACHES...FEELING IS THAT MCS WILL BREAK
THROUGH THE MID LEVEL DOME AND ALLOW FOR SOUTH PROGRESSION. MAIN
THREATS ARE THUNDERSTORM WINDS IN EXCESS OF 60KT IF THE STORMS CAN
FOLLOW THE MOISTURE AXIS. HAIL ALSO A THREAT. ACTIVITY TO ARRIVE AFT
02Z AT KFOD...05Z AT KDSM...AND AROUND 04Z AT KMCW/KALO. HAVE
ARRIVAL TIME AT KOTM AFT 08Z. SEVERAL HOURS OF STORMS ARE EXPECTED.
BY 11Z...SOME IFR BR EXPECTED WHICH WILL GIVE WAY TO CB AND ISO
THUNDER AFT 15-18Z TIME FRAME. MORE UNCERTAINTY THERE...SO HAVE NOT
HIT LATER HOURS WITH CATEGORICAL WX FOR NOW./REV

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR APPANOOSE-
BOONE-CALHOUN-CLARKE-DALLAS-DAVIS-DECATUR-GREENE-HAMILTON-
JASPER-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-
PALO ALTO-POCAHONTAS-POLK-POWESHIEK-STORY-WAPELLO-
WARREN-WAYNE-WEBSTER.

FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
MORNING FOR ADAIR-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-
CRAWFORD-DALLAS-GREENE-GUTHRIE-HAMILTON-JASPER-MADISON-
MARSHALL-POCAHONTAS-POLK-SAC-STORY-WARREN-WEBSTER.

EXCESSIVE HEAT WARNING UNTIL 7 PM CDT MONDAY FOR ADAIR-
ADAMS-AUDUBON-CARROLL-CASS-CRAWFORD-GUTHRIE-RINGGOLD-SAC-
TAYLOR-UNION.

&&

SHORT TERM...MS AUG 10
LONG TERM...MJB
AVIATION...REV
Hazardous weather outlook, Aug 8, 4:12 PM CST, 2 hours 53 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
512 PM CDT SUN AUG 8 2010

IAZ033-044-045-057-058-070-071-092215-
SAC-CRAWFORD-CARROLL-AUDUBON-GUTHRIE-CASS-ADAIR-
512 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 THIS EVENING AND TONIGHT. STORMS
MAY BE SEVERE WITH SEVERE WINDS TO 70 MPH THE PRIMARY THREAT.
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-
512 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-
512 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. 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-
512 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 NORTH OF U.S. 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

The radar

The Des Moines radar (KDMX), 156 km away, was scanning. The volume nearest the first event began at 01:05 UTC.

Open the radar archive at this moment

Event by event

27 thunderstorm wind, 20 flash flood, 19 heavy rain, 3 lightning, 1 funnel cloud, 1 flood. Local standard time, as filed.

Thunderstorm Wind, Sac

When
August 8, 7:05 PM CST
Where
Sac County, Schaller
Measured
56 kt (64 mph) estimated gust
Property damage
$2,000
Reported by
Trained Spotter
Coordinates
42.500, -95.300

Small branches were down as well as other damage to power lines.

Thunderstorm Wind, Sac

When
August 8, 7:10 PM CST
Where
Sac County, Schaller
Measured
61 kt (70 mph) estimated gust
Property damage
$300,000
Crop damage
$15,000
Reported by
Trained Spotter
Coordinates
42.500, -95.300

Trees down and uprooted. Power lines down with some trees snapped.

Thunderstorm Wind, Calhoun

When
August 8, 7:25 PM CST
Where
Calhoun County, 2.22 mi NNE of Lytton
Measured
57 kt (66 mph) estimated gust
Property damage
$5,000
Reported by
Trained Spotter
Coordinates
42.460, -94.856

Large trees uprooted and large limbs downed by high winds.

Thunderstorm Wind, Calhoun

When
August 8, 7:37 PM CST
Where
Calhoun County, 3.69 mi SE of Jolley
Measured
62 kt (71 mph) measured gust
Property damage
$5,000
Crop damage
$50,000
Reported by
Public
Coordinates
42.450, -94.660

Six to 10 inch tree limbs down. Crop damage reported.

Thunderstorm Wind, Calhoun

When
August 8, 7:41 PM CST
Where
Calhoun County, Rockwell City
Measured
54 kt (62 mph) measured gust
Property damage
$3,000
Reported by
Law Enforcement
Coordinates
42.400, -94.630

Two large trees down in town.

Thunderstorm Wind, Pocahontas

When
August 8, 7:45 PM CST
Where
Pocahontas County, 1.02 mi W of Fonda
Measured
61 kt (70 mph) estimated gust
Property damage
$2,000
Reported by
NWS Employee
Coordinates
42.580, -94.850

Off-duty Sioux Falls NWS employee reported strong winds.

Thunderstorm Wind, Pocahontas

When
August 8, 7:45 PM CST
Where
Pocahontas County, 1.02 mi W of Fonda
Measured
61 kt (70 mph) estimated gust
Property damage
$25,000
Reported by
Law Enforcement
Coordinates
42.580, -94.850

Walls of brick buildings destroyed on main street and a 40,000 bushel grain bin was destroyed.

Thunderstorm Wind, Pocahontas

When
August 8, 7:45 PM CST
Where
Pocahontas County, 1.01 mi W of Laurens
Measured
57 kt (66 mph) estimated gust
Property damage
$15,000
Reported by
Storm Chaser
Coordinates
42.850, -94.870

Three foot diameter trees and large limbs were blown down.

Funnel Cloud, Carroll

When
August 8, 7:50 PM CST
Where
Carroll County, 1.54 mi E of Templeton
Reported by
Trained Spotter
Coordinates
41.920, -94.920

Brief funnel clouds forming and dissipating.

Thunderstorm Wind, Calhoun

When
August 8, 7:50 PM CST
Where
Calhoun County, Pomeroy
Measured
61 kt (70 mph) estimated gust
Property damage
$15,000
Reported by
NWS Employee
Coordinates
42.550, -94.680

Off Duty Sioux Falls NWS employee reported trees and street signs down in town.

Thunderstorm Wind, Emmet

When
August 8, 7:53 PM CST
Where
Emmet County, 0.5 mi E of Wellingford
Measured
61 kt (70 mph) estimated gust
Property damage
$25,000
Reported by
Fire Department/Rescue
Coordinates
43.320, -94.790

Fire chief reported a roof blown off in Wallingford.

Thunderstorm Wind, Palo Alto

When
August 8, 7:58 PM CST
Where
Palo Alto County, 1.22 mi NE of Graettinger
Measured
57 kt (66 mph) estimated gust
Property damage
$25,000
Reported by
Law Enforcement
Coordinates
43.240, -94.750

Local law enforcement reported streets closed due to downed trees in Graettinger.

Heavy Rain, Greene

When
August 8, 8:00 PM CST to 9:13 PM CST
Where
Greene County, 0.69 mi S of Jefferson
Reported by
Trained Spotter
Coordinates
42.010, -94.380

Rainfall since 2000 CST was 2.15 inches.

Heavy Rain, Greene

When
August 8, 8:00 PM CST to 11:03 PM CST
Where
Greene County, 0.69 mi S of Jefferson
Reported by
Trained Spotter
Coordinates
42.010, -94.380

Rainfall since 2000 CST was 3.1 inches.

Flash Flood, Sac

When
August 8, 8:00 PM CST to August 9, 4:44 AM CST
Where
Sac County, 0.69 mi S of Lytton to 0.88 mi S of Lytton
Cause
Heavy Rain
Property damage
$25,000
Reported by
Law Enforcement
Coordinates
42.420, -94.870

Sac County law enforcement reports flooding over Highway 20 near Lytton.

Lightning, Carroll

When
August 8, 8:00 PM CST
Where
Carroll County, Carroll
Property damage
$2,000
Reported by
Newspaper
Coordinates
42.070, -94.880

Thunderstorm Wind, Webster

When
August 8, 8:13 PM CST
Where
Webster County, 2.95 mi NNW of Roelyn
Measured
52 kt (60 mph) estimated gust
Property damage
$1,000
Reported by
Trained Spotter
Coordinates
42.460, -94.370

Trained spotter estimated a wind gust of 60 MPH.

Thunderstorm Wind, Kossuth

When
August 8, 8:22 PM CST
Where
Kossuth County, 0.86 mi NE of Algona
Measured
52 kt (60 mph) estimated gust
Property damage
$2,000
Reported by
Trained Spotter
Coordinates
43.080, -94.220

Strong winds were bending trees and blowing patio furniture over.

Thunderstorm Wind, Webster

When
August 8, 8:22 PM CST
Where
Webster County, 1.23 mi NW of (Fod)ft Dodge Muni A
Measured
52 kt (60 mph) estimated gust
Reported by
Trained Spotter
Coordinates
42.560, -94.200

Strong winds blowing small objects and bending trees significantly.

Thunderstorm Wind, Emmet

When
August 8, 8:23 PM CST
Where
Emmet County, 0.5 mi E of Wellingford
Measured
57 kt (66 mph) estimated gust
Property damage
$5,000
Reported by
Law Enforcement
Coordinates
43.320, -94.790

Wind blew the roof off of the Wallingford Community Center.

Thunderstorm Wind, Humboldt

When
August 8, 8:24 PM CST
Where
Humboldt County, 0.51 mi W of Dakota City
Measured
50 kt (58 mph) measured gust
Reported by
Trained Spotter
Coordinates
42.720, -94.230

Thunderstorm Wind, Wright

When
August 8, 8:41 PM CST
Where
Wright County, 0.51 mi W of Eagle Grove
Measured
50 kt (58 mph) measured gust
Reported by
Trained Spotter
Coordinates
42.670, -93.910

Thunderstorm Wind, Boone

When
August 8, 8:58 PM CST
Where
Boone County, Boone Muni Arpt
Measured
54 kt (62 mph) measured gust
Property damage
$5,000
Reported by
Trained Spotter
Coordinates
42.050, -93.850

Heavy Rain, Palo Alto

When
August 8, 9:00 PM CST
Where
Palo Alto County, 1.22 mi SE of Emmetsburg
Reported by
Public
Coordinates
43.110, -94.680

Public reports very heavy rain in Emmetsburg with water 3-4 inches deep on Highway 18.

Thunderstorm Wind, Story

When
August 8, 9:04 PM CST
Where
Story County, 1.47 mi NNW of Ames
Measured
52 kt (60 mph) estimated gust
Property damage
$2,000
Reported by
Trained Spotter
Coordinates
42.050, -93.630

A trained spotter estimated wind speed of 60 MPH.

Thunderstorm Wind, Dallas

When
August 8, 9:09 PM CST
Where
Dallas County, 2.08 mi SE of Waukee
Measured
52 kt (60 mph) estimated gust
Property damage
$30,000
Reported by
Trained Spotter
Coordinates
41.600, -93.870

Ten to 15 foot mature tree blown down at Centennial Park.

Heavy Rain, Polk

When
August 8, 9:15 PM CST to August 9, 12:03 AM CST
Where
Polk County, 2.08 mi NE of Commerce
Reported by
Trained Spotter
Coordinates
41.550, -93.740

Rainfall of 3.80 inches since 2115 CDT, 1.5 inches in the 45 minutes from 2315-2400.

Flash Flood, Carroll

When
August 8, 9:15 PM CST to 11:54 PM CST
Where
Carroll County, 1.42 mi SE of Carroll to 1.04 mi NE of Carroll
Cause
Heavy Rain
Property damage
$100,000
Reported by
Law Enforcement
Coordinates
42.057, -94.859

Three to four feet of standing water on city streets.

Flash Flood, Carroll

When
August 8, 9:20 PM CST to 11:54 PM CST
Where
Carroll County, 1.04 mi SSW of Glidden to 1.16 mi SW of Glidden
Cause
Heavy Rain
Property damage
$50,000
Reported by
Law Enforcement
Coordinates
42.055, -94.735

One and a half feet of slowly flowing water on streets in Glidden.

Thunderstorm Wind, Franklin

When
August 8, 9:25 PM CST
Where
Franklin County, Hampton
Measured
57 kt (66 mph) estimated gust
Property damage
$20,000
Reported by
Newspaper
Coordinates
42.750, -93.200

High winds from a thunderstorms downed 14 trees, many uprooted.

Flash Flood, Greene

When
August 8, 9:32 PM CST to 11:54 PM CST
Where
Greene County, Rippey to 0.37 mi NNE of Rippey
Cause
Heavy Rain
Property damage
$50,000
Reported by
Trained Spotter
Coordinates
41.930, -94.200

Trained spotter in Rippey reports fast flowing water about 6 inches deep in the streets. The city park was largely under water as well.

Thunderstorm Wind, Marshall

When
August 8, 9:38 PM CST
Where
Marshall County, 0.86 mi SE of Marshalltown
Measured
52 kt (60 mph) estimated gust
Property damage
$2,000
Reported by
Trained Spotter
Coordinates
42.040, -92.910

Tree branches were blown down by 60 MPH winds.

Lightning, Dallas

When
August 8, 9:45 PM CST
Where
Dallas County, 1.95 mi NNW of Adel
Property damage
$1.0 million
Reported by
Fire Department/Rescue
Coordinates
41.647, -94.030

Flash Flood, Greene

When
August 8, 9:45 PM CST to August 9, 3:00 AM CST
Where
Greene County, Rippey to 0.28 mi N of Rippey
Cause
Heavy Rain
Property damage
$50,000
Reported by
Trained Spotter
Coordinates
41.930, -94.200

Water 3 to 4 inches deep in yards, water over curbs, city park and city ball field beginning to flood.

Thunderstorm Wind, Butler

When
August 8, 9:45 PM CST
Where
Butler County, Bristow
Measured
52 kt (60 mph) estimated gust
Property damage
$5,000
Reported by
Newspaper
Coordinates
42.770, -92.920

High winds blew trees down in Bristow, snapping trees.

Thunderstorm Wind, Marshall

When
August 8, 9:49 PM CST
Where
Marshall County, 2.92 mi NE of Marshalltown
Measured
56 kt (64 mph) estimated gust
Property damage
$25,000
Reported by
Trained Spotter
Coordinates
42.080, -92.880

Power was knocked out by winds of 65 MPH.

Heavy Rain, Polk

When
August 8, 10:00 PM CST
Where
Polk County, 1.38 mi S of Des Moines
Reported by
Amateur Radio
Coordinates
41.580, -93.620

Street flooding at NW 6TH and Aurora in Highland Park. Rainfall was 1.5 inches.

Heavy Rain, Jasper

When
August 8, 10:00 PM CST to August 9, 3:58 AM CST
Where
Jasper County, 2.07 mi SW of Newton
Reported by
Trained Spotter
Coordinates
41.680, -93.080

Rain since 2200 CST was 4.05 inches.

Heavy Rain, Boone

When
August 8, 10:00 PM CST to August 9, 7:00 AM CST
Where
Boone County, 2.31 mi SSW of Boone Muni Arpt
Reported by
NWS Employee
Coordinates
42.020, -93.870

Overnight total was 4.71 inches.

Heavy Rain, Polk

When
August 8, 10:10 PM CST
Where
Polk County, 1.38 mi S of Des Moines
Reported by
Amateur Radio
Coordinates
41.580, -93.620

Street flooding at 14th and Euclid.

Thunderstorm Wind, Bremer

When
August 8, 10:12 PM CST
Where
Bremer County, 1.47 mi SSW of Plainfield
Measured
56 kt (64 mph) measured gust
Reported by
Mesonet
Coordinates
42.830, -92.540

Thunderstorm Wind, Guthrie

When
August 8, 10:20 PM CST
Where
Guthrie County, 2.57 mi W of Bayard
Measured
52 kt (60 mph) estimated gust
Property damage
$1,000
Reported by
Trained Spotter
Coordinates
41.850, -94.620

Sweet corn was completely blown over with small branches down.

Thunderstorm Wind, Bremer

When
August 8, 10:30 PM CST
Where
Bremer County, 0.86 mi NW of Tripoli
Measured
52 kt (60 mph) estimated gust
Property damage
$2,000
Reported by
Broadcast Media
Coordinates
42.810, -92.260

Several tree limbs and branches down in Tripoli.

Heavy Rain, Polk

When
August 8, 10:30 PM CST to August 9, 1:30 AM CST
Where
Polk County, 0.69 mi N of Windsor Hgts
Reported by
Trained Spotter
Coordinates
41.610, -93.720

Rainfall over the past 4 hours was 4.10 inches.

Flash Flood, Dallas

When
August 8, 10:33 PM CST to August 9, 3:30 AM CST
Where
Dallas County, 0.66 mi SSE of Waukee to 0.38 mi ESE of Waukee
Cause
Heavy Rain
Property damage
$25,000
Reported by
Broadcast Media
Coordinates
41.612, -93.893

Four to six inches of water over Highway 6 at Highway R22.

Heavy Rain, Polk

When
August 8, 10:42 PM CST
Where
Polk County, 0.52 mi E of Clover Hills
Reported by
Utility Company
Coordinates
41.600, -93.740

Stranded cars at 86th and University.

Lightning, Black Hawk

When
August 8, 10:45 PM CST
Where
Black Hawk County, Cedar Falls
Property damage
$50,000
Reported by
Newspaper
Coordinates
42.520, -92.450

Heavy Rain, Story

When
August 8, 11:00 PM CST to August 9, 4:05 AM CST
Where
Story County, 0.69 mi N of Nevada
Reported by
Trained Spotter
Coordinates
42.030, -93.450

Rain since 2300 CST was 3.80 inches.

Heavy Rain, Polk

When
August 8, 11:00 PM CST to August 9, 4:05 AM CST
Where
Polk County, 0.86 mi SW of Rider
Reported by
CoCoRaHS
Coordinates
41.660, -93.790

Rainfall since midnight was 3.80 inches.

Heavy Rain, Polk

When
August 8, 11:00 PM CST to August 9, 5:38 AM CST
Where
Polk County, 0.52 mi E of Altoona
Reported by
Trained Spotter
Coordinates
41.650, -93.460

Since last evening, 3.04 inches of rain fell.

Heavy Rain, Story

When
August 8, 11:39 PM CST
Where
Story County, 0.86 mi SW of Ames
Reported by
Law Enforcement
Coordinates
42.020, -93.630

Numerous roads flooded due to to poor drainage including South Dakota, Mortensen, and Lincoln Way. Water to the undercarriages of cars with some stalled.

Heavy Rain, Monroe

When
August 9, 12:00 AM CST to 5:10 AM CST
Where
Monroe County, 1.04 mi E of Albia
Reported by
Trained Spotter
Coordinates
41.030, -92.800

Measured rainfall since midnight was 4.06 inches. Standing water in yard.

Flash Flood, Boone

When
August 9, 12:17 AM CST to 7:30 AM CST
Where
Boone County, 4.14 mi SW of Ericson to 2.95 mi E of Luther
Cause
Heavy Rain
Property damage
$25,000
Reported by
Emergency Manager
Coordinates
41.981, -93.862

Water over Highway 17 north of Luther, water running into homes and over roads in Moingona in southern Boone County.

Flash Flood, Polk

When
August 9, 1:15 AM CST to 6:00 AM CST
Where
Polk County, 0.31 mi NNE of Windsor Hgts to 1.27 mi ESE of Windsor Hgts
Cause
Heavy Rain
Property damage
$300,000
Reported by
Newspaper
Coordinates
41.604, -93.718

Four lower level basement units in an eight unit apartment building were inundated with water and three houses nearby on NW 75th Street were damaged due to fast rising flood waters from North Walnut Creek. Water was chest deep in one apartment with firefighters having to break into apartments with an axe. Water was knee to waist high in the yard of one of the houses. The creek came up in roughly 45 minutes. The nearby Walnut Creek had a record crest early the morning of the 9th.

Flash Flood, Polk

When
August 9, 1:25 AM CST to 4:00 AM CST
Where
Polk County, Rider to 0.58 mi NNE of Rider
Cause
Heavy Rain
Property damage
$25,000
Reported by
NWS Employee
Coordinates
41.670, -93.780

Water flowing out of corn field and across south 19th St between Little Beaver and Highway 141. Depth of flowing water was 6 to 8 inches.

Heavy Rain, Jasper

When
August 9, 1:30 AM CST
Where
Jasper County, 2.07 mi SW of Newton
Reported by
Trained Spotter
Coordinates
41.680, -93.080

Rainfall since 2200 CST.

Flash Flood, Polk

When
August 9, 1:59 AM CST to 4:00 AM CST
Where
Polk County, 1.36 mi E of West Des Moines to 1.39 mi ESE of West Des Moines
Cause
Heavy Rain
Property damage
$75,000
Reported by
County Official
Coordinates
41.579, -93.694

Public Works Department in Des Moines and West Des Moines reports water over the road at Grand and 61st.

Flash Flood, Dallas

When
August 9, 3:00 AM CST to 3:30 AM CST
Where
Dallas County, 0.52 mi W of Dallas Center to 0.99 mi NNE of Shuler Mine
Cause
Heavy Rain
Property damage
$25,000
Reported by
Law Enforcement
Coordinates
41.680, -93.980

Highway 44 just east of X Ave has running water over the road. Moderate street flooding in Dallas Center.

Heavy Rain, Carroll

When
August 9, 3:20 AM CST
Where
Carroll County, 0.69 mi S of Lidderdale
Reported by
Trained Spotter
Coordinates
42.120, -94.780

Overnight rainfall was 2.30 inches.

Heavy Rain, Hamilton

When
August 9, 3:32 AM CST
Where
Hamilton County, 5.67 mi E of Randall
Reported by
Trained Spotter
Coordinates
42.220, -93.490

Overnight rainfall was 2.60 inches.

Flash Flood, Story

When
August 9, 3:41 AM CST to 7:30 AM CST
Where
Story County, 1 mi WSW of Ames Arpt to 0.52 mi W of Ames Arpt
Cause
Heavy Rain
Property damage
$5,000
Reported by
Law Enforcement
Coordinates
41.996, -93.639

Airport road closed from Riverside to North Loop due to water over the road.

Flash Flood, Polk

When
August 9, 3:42 AM CST to 4:00 AM CST
Where
Polk County, 1.13 mi NNE of Youngstown to 1.14 mi E of Youngstown
Cause
Heavy Rain
Property damage
$500,000
Reported by
Emergency Manager
Coordinates
41.595, -93.520

Polk County reports flash flooding in the 4300 block of Fairview near Dean Ave. Flood waters washed away railroad tracks and caused a derailment.

Flash Flood, Story

When
August 9, 3:42 AM CST to 7:30 AM CST
Where
Story County, 1.72 mi SE of Iowa Center to 1.46 mi S of Iowa Center
Cause
Heavy Rain
Property damage
$25,000
Reported by
Law Enforcement
Coordinates
41.910, -93.400

Story County Sheriff reports water over the road on County Highway S27 just north of Maxwell, near the Rolling Hills Mobile Home Park.

Flash Flood, Story

When
August 9, 3:42 AM CST to 7:30 AM CST
Where
Story County, 0.86 mi SW of Ames to 1.25 mi ESE of Ames
Cause
Heavy Rain
Property damage
$25,000
Reported by
Law Enforcement
Coordinates
42.020, -93.630

Story County Sheriff reports Highway 69 closed from Ames south to mile post 111 due to water over the road.

Flash Flood, Boone

When
August 9, 4:03 AM CST to 6:30 AM CST
Where
Boone County, 1.38 mi S of Boone to 0.27 mi SW of Jordan
Cause
Heavy Rain
Property damage
$50,000
Reported by
Law Enforcement
Coordinates
42.050, -93.880

Boone County law reports numerous roads flooded in town as well as flooding along old Highway 30 at Highway 17.

Flash Flood, Story

When
August 9, 4:30 AM CST to 7:30 AM CST
Where
Story County, Cambridge to 0.68 mi N of Cambridge
Cause
Heavy Rain
Property damage
$75,000
Reported by
Trained Spotter
Coordinates
41.900, -93.530

Over 5 inches of rain overnight with street flooding on Pearl Street. Depth of water was up to the door on a pickup truck.

Flash Flood, Story

When
August 9, 5:30 AM CST to 7:30 AM CST
Where
Story County, 1.03 mi E of Kelley to 0.46 mi ENE of Kelley
Cause
Heavy Rain
Property damage
$25,000
Reported by
Trained Spotter
Coordinates
41.950, -93.660

Deep water flowing over the road from a field outside of Kelley and water reported over roads in Kelley.

Flash Flood, Mahaska

When
August 9, 5:30 AM CST to 9:00 AM CST
Where
Mahaska County, 4 mi WSW of Lakonta to 2.48 mi W of Lakonta
Cause
Heavy Rain
Property damage
$10,000
Reported by
SHAVE Project
Coordinates
41.184, -92.824

Flooding of fields has occurred due to local stream overflowing its banks by as much as three-quarters of a mile. Numerous streets flooded due to ditches overflowing their banks. Some of the streets had 6 to 8 inches of rushing water over them. 310th street was closed just to the northeast of Bussey due to flooding.

Heavy Rain, Webster

When
August 9, 7:02 AM CST
Where
Webster County, 0.51 mi E of Gowrie
Reported by
Trained Spotter
Coordinates
42.280, -94.290

Water over country roads with 3.50 inches of rainfall.

Flood, Story

When
August 9, 7:49 AM CST to 7:30 PM CST
Where
Story County, Cambridge to 0.42 mi WNW of Cambridge
Cause
Heavy Rain
Property damage
$250,000
Reported by
Emergency Manager
Coordinates
41.900, -93.530

Significant flooding reported in the town of Cambridge.

Flash Flood, Wapello

When
August 9, 9:00 AM CST to 10:00 AM CST
Where
Wapello County, 2.95 mi ENE of Agency to 3.73 mi NE of Agency
Cause
Heavy Rain
Property damage
$10,000
Reported by
SHAVE Project
Coordinates
41.000, -92.320

Resident had knee deep water on his property that runs off from the farm land near his home. He said it usually is retained by terraces and trenches in the fields but they were not able to keep up.

What these are

Thunderstorm Wind
Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Funnel Cloud
A rotating column of cloud extending from a thunderstorm that did not reach the ground.
Heavy Rain
Rainfall totals unusual for the place and season that did not produce a flood.
Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Lightning
A lightning strike that killed, injured or caused damage.
Flood
Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Iowa in 2010Every state in 2010This day in weather historyWarnings in Iowa, August 2010

Sources

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: 239353, 239354, 239374, 239358, 239359, 239367, 239370, 239375, 239352, 239368, 239372, 239373, 239648, 239652, 239720, 248624, 239360, 239361, 239365, 239369, 239363, 239366, 239376, 239653, 239378, 239644, 239654, 239721, 239723, 254798, 239725, 239379, 239383, 239764, 250702, 239381, 239649, 239662, 239666, 239650, and more.