Flash Flooding and Flooding in Iowa, May 6 to 7, 2008

Name: Flash Flooding and Flooding in Iowa, May 6 to 7, 2008
Start: 2008-05-06T15:47
End: 2008-05-07T10:17
Location: Iowa

May 6 to 7, 2008 · NWS DMX · 33 events in 15 counties and zones

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: $438,000
Crop damage: None recorded
Events: 33

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 strong push of warm and unstable air pushed north into Iowa during the day on the 6th. Surface temperatures warmed into the upper 70s to mid 80s across the state, with dew point readings in the 55 to 60 degree range. A cold front moved into the state from the northwest as an upper level short wave lifted northeast across the state during the evening. Most unstable CAPE values were in the 1000-2000 J/kg range by the late afternoon. There was sufficient shear available with the effective shear in the 40 to 50 kt range across the north half of the state. The LCL was quite high, in the 1250 to 1500 meter range. Cape in the -10 to -30 C. layer of the atmosphere had around 200 J/kg of CAPE available. Downdraft CAPE was in the 700 to 900 J/kg range as the soundings indicated an inverted V structure. The freezing level was around 12,000 feet. Thunderstorms fired in a broken line extending from the far northwest corner of Iowa, southwest into Nebraska. The storms became severe quite quickly as they advanced east. Many of the storms produced hail of around one half inch in diameter or so. Several produced hail of three quarters of an inch to one inch in diameter. The hail would have likely been larger if not for the lack of significant CAPE in the -10 to -30 C. layer. As the line evolved, it became solid from north central into west central Iowa. Initially, the northern part of the line took on a bow echo configuration and produced high winds across north central into northeast Iowa. The winds blew over a semi-tractortrailer rig near the 197 mile post on Interstate 35. The bow echo feature continued east into northeast Iowa. As the line moved through Bremer County, high winds blew down road signs and caused damage at the Wal-Mart store there. This feature left an outflow boundary extending east to west across central Iowa. The boundary provided the focal point for additional thunderstorms, which trained across parts of central into northeast Iowa. Farther to the west, many of the storms produced hail and some heavy rainfall. Flooding became a problem with many areas reporting small stream and urban flooding. Flash flooding, as well as areal flooding, became a problem over Wright and Hardin Counties where 3 to 5 inches of rain fell. One of the harder hit areas was in Hardin County at Alden where nearly 5 inches of rain was reported in under three hours. A report of 6.25 inches was received from west of Iowa Falls in Hardin County. This was over a period of six and one half hours. Numerous roads were closed in these two counties with water anywhere from 6 to 24 inches deep running across the roads. In addition, heavy rain fell in the city of Boone in Boone County with water reportedly flowing 6 to 12 inches deep over a number of roads. There were several road closures in the city of Boone.

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 May 6, 2:00 PM CST, 1 hour 47 minutes earlier.

Area forecast discussion, May 6, 2:00 PM CST, 1 hour 47 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
300 PM CDT TUE MAY 6 2008

.SHORT TERM /TONIGHT/...
MAIN SYNOPTIC SCALE WARM FRONT IS WELL NORTH INTO MINNESOTA THIS
AFTERNOON...BUT MESOSCALE BOUNDARIES SET DOWN BY CONVECTIVE
COMPLEXES IN SOUTHERN MINNESOTA TO NORTHERN NEBRASKA WILL BE
LAUNCHING OR SUSTAINING POINT FOR ADDITIONAL CONVECTION THIS
EVENING. CURRENT SPEED OF SMALL BOWING SEGMENT OVER SOUTHEAST SOUTH
DAKOTA PUTS IT INTO PALO ALTO COUNTY BY 530 PM. CU FIELD THAT HAS
DEVELOPED OVER CENTRAL IA WITH DAYTIME HEATING COULD ALSO RANDOMLY
FIRE UP A FEW STORMS...BUT SO FAR MIXED LAYER CAPE REMAINS LOW...AND
THERE DOES NOT APPEAR TO BE A FOCUS FOR LOW LEVEL CONVERGENCE. THE
MAIN SHOW SHOULD BE CONVECTIVE COMPLEX MOVING ACROSS NORTHERN IA
THIS EVENING...WITH POTENTIAL FOR SEVERE WEATHER IN FORM OF LARGE
HAIL AND DAMAGING WIND...GIVEN STEEP LAPSE RATES AND RELATIVELY LOW
FREEZING HEIGHTS. THE OTHER CONCERN FOR TONIGHT ARRIVES LATER WHEN
ANOTHER CONVECTIVE COMPLEX THAT IS EXPECTED TO GET GOING IN CENTRAL
NEBRASKA SCOOTS SLIGHTLY SOUTH OF EAST AND SKIRTS OVER OR NEAR
SOUTHERN IOWA AFTER MIDNIGHT. THIS FEATURE WILL HAVE STRONG MOISTURE
TRANSPORT INTO IT...SO THIS MAY END UP BEING MORE OF A SHORT-FUSED
HYDROLOGIC CONCERN. THE QUESTION STILL REMAINS EXACTLY WHERE THE
HEAVIEST BAND OF THUNDERSTORMS WILL TRACK. JUST A SLIGHT SOUTHWARD
SHIFT IN THE TRACK WILL TAKE IT ACROSS NORTHERN MISSOURI. COLD FRONT
WILL BE ENTERING OUR NORTHWEST COUNTIES AFT 4 AM WITH A LEADING EDGE
OF COOLER AND DRIER AIR.

&&

.LONG TERM /WED THROUGH TUE/...
ISOLD HEAVY RAIN THREAT SHOULD CONTINUE FOR A FEW HOURS PAST DAY
BREAK WEDNESDAY IN FAR SOUTHERN IOWA WITH LINGERING STRONG MOISTURE
CONVERGENCE AXIS NEAR THE BOUNDARY ALONG THE IOWA MISSOURI BORDER.
THE FRONT WILL THEN PUSH SOUTH OF IOWA AROUND MIDDAY...WITH LITTLE
OR NO ADDITIONAL RAINFALL EXPECTED DURING THE AFTERNOON. THE MAX
TEMPERATURES FORECAST FOR WEDNESDAY WILL BE TRICKY WITH CAA NORTH
AND MORE PRECIP/CLOUDS SOUTH. WILL BANK ON ENOUGH BREAKS IN THE
CLOUDS TO BUMP UP TEMPS CENTRAL AND SOUTH TO AROUND 70 BEFORE THE
COOLER AIR LAGGING BEHIND THE FRONT SWEEPS THROUGH IN THE AFTERNOON.
THE NAM/GFS/SREF ARE ALL INDICATING MORE SHORT WAVE ENERGY TO IMPACT
IOWA THURSDAY NIGHT INTO FRIDAY. HAVE LEFT THE FRIDAY PERIOD DRY FOR
COORDINATION PURPOSES...BUT FUTURE SHIFTS WILL HAVE TO RE-EVALUATE.
BETTER CHANCES FOR CONVECTION ARE STILL FOCUSED ON SATURDAY AND
SATURDAY NIGHT...BASED ON THE GEM/ECMWF/GFS AND ENSEMBLE CONSENSUS.
THE SEVERE WEATHER THREAT LOOKS TO BE MINIMAL.

LOOKING AHEAD TO SUNDAY THROUGH TUESDAY...MODEL CONSENSUS IS STILL
SHAKY BUT DECIDED TO PULL POPS FROM SUNDAY NIGHT AND MONDAY AHEAD OF
THE NEXT SYSTEM. THE ECMWF DEVELOPS A MUCH DEEPER WESTERN CONUS TROF
THAN THE GFS AND IS SLOWER BRINGING THE SYSTEM INTO IOWA EARLY NEXT
WEEK.

&&

.AVIATION...06/18Z
CONVECTIVE DETAILS PROBLEMATIC IN THIS TAF PACKAGE. DO NOT EXPECT
ANY ORGANIZED TSTMS THRU 00Z. THEREAFTER...COMPLEX OF TSTMS OVER
SOUTHEAST SD WILL MOVE ACROSS NRN IA...BUT SHOULD BE CLEARED BY
08Z...WITH IFR/MVFR CEILINGS AND SCATTERED SHRA FOR A FEW HOURS
AFTER. KDSM HAS THE LOWEST CONFIDENCE OF GETTING TSRA SO HANDLED
THAT WITH A CB REMARK FOR PERIOD OF GREATEST CONCERN. ANOTHER
CONVECTIVE COMPLEX EXPECTED TO ROLL EAST ACROSS THE IA/MO BORDER
LATE TONIGHT MAY AFFECT KOTM AFT 09Z.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

SHORT TERM/AVIATION...MOYER
LONG TERM...KINNEY

Hazardous weather outlook, May 6, 2:46 PM CST, 1 hour 1 minute before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
346 PM CDT TUE MAY 6 2008

IAZ027-028-037>039-044>050-057>062-070>075-081>086-092>097-072100-
BUTLER-BREMER-HARDIN-GRUNDY-BLACK HAWK-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-
346 PM CDT TUE MAY 6 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

ISOLATED THUNDERSTORMS ARE FORECAST LATE THIS AFTERNOON AND MAY
POSSIBLY INCREASE IN COVERAGE AND INTENSITY THIS EVENING. SEVERE
STORMS REMAIN POSSIBLE LATE THIS AFTERNOON INTO THIS EVENING WITH
THE MAIN THREAT FROM DAMAGING HAIL AND WINDS. AMPLE MOISTURE MAY
ALSO LEAD TO HEAVY RAIN FROM THESE STORMS PRODUCING LOCALIZED
FLOODING OVERNIGHT...ESPECIALLY SOUTH OF INTERSTATE 80.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE THREAT FOR ADDITIONAL NON SEVERE THUNDERSTORMS WILL CONTINUE
ACROSS FAR SOUTHERN IOWA THROUGH WEDNESDAY INTO WEDNESDAY EVENING.
AN ADDITIONAL THREAT FOR NON SEVERE THUNDERSTORMS EXISTS ON
SATURDAY INTO SATURDAY NIGHT AS WELL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND EVENING.
ANY HEAVY RAINFALL REPORTS WOULD ALSO BE APPRECIATED.

IAZ005-024-072100-
KOSSUTH-HUMBOLDT-
346 PM CDT TUE MAY 6 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL BECOME MORE NUMEROUS LATE THIS AFTERNOON AND
EARLY TONIGHT...WITH A FEW SEVERE STORMS POSSIBLE. THE MAIN THREAT FROM
THESE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS. LOCALIZED
HEAVY RAIN MAY ALSO OCCUR WITH THESE STORMS.

A FLOOD WARNING IS ALSO IN EFFECT FOR THE PORTIONS OF THE UPPER
DES MOINES RIVER BASIN. PLEASE REFER TO THE NATIONAL WEATHER
SERVICE WEBSITE AT WEATHER.GOV/DESMOINES.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SEVERAL CHANCES FOR NON SEVERE THUNDERSTORMS EXISTS ON LATE
THURSDAY INTO THURSDAY NIGHT AND AGAIN ON SATURDAY INTO SATURDAY
NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND EVENING.
ANY REPORTS OF HEAVY RAINFALL WOULD ALSO BE APPRECIATED.

IAZ004-006-007-015>017-023-025-026-033>036-072100-
EMMET-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-POCAHONTAS-
WRIGHT-FRANKLIN-SAC-CALHOUN-WEBSTER-HAMILTON-
346 PM CDT TUE MAY 6 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL BECOME MORE NUMEROUS LATE THIS AFTERNOON AND
EARLY TONIGHT...WITH A FEW SEVERE STORMS POSSIBLE. THE MAIN THREAT FROM
THESE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS. LOCALIZED
HEAVY RAIN MAY ALSO OCCUR WITH THESE STORMS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SEVERAL CHANCES FOR NON SEVERE THUNDERSTORMS EXISTS ON LATE
THURSDAY INTO THURSDAY NIGHT AND AGAIN ON SATURDAY INTO SATURDAY
NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND EVENING.
ANY REPORTS OF HEAVY RAINFALL WOULD ALSO BE APPRECIATED.

MOYER

The radar

The Sioux Falls radar (KFSD), 155 km away, was scanning. The volume nearest the first event began at 21:47 UTC.

Open the radar archive at this moment

Event by event

15 hail, 6 heavy rain, 6 thunderstorm wind, 3 flash flood, 3 flood. Local standard time, as filed.

Hail, Emmet

When: May 6, 3:47 PM CST
Where: Emmet County, 1.71 mi SE of Estherville
Measured: 0.75 in hail
Reported by: Emergency Manager
Coordinates: 43.400, -94.830

Hail reportedly covered the ground.

Hail, Emmet

When: May 6, 3:52 PM CST
Where: Emmet County, 1.22 mi SE of Gruver
Measured: 0.75 in hail
Reported by: Emergency Manager
Coordinates: 43.390, -94.700

Hail, Emmet

When: May 6, 3:58 PM CST
Where: Emmet County, 1.22 mi SE of Armstrong
Measured: 0.75 in hail
Reported by: Emergency Manager
Coordinates: 43.390, -94.480

Hail, Palo Alto

When: May 6, 4:01 PM CST
Where: Palo Alto County, 2.89 mi NE of Ruthven
Measured: 1 in hail
Property damage: $3,000
Reported by: Emergency Manager
Coordinates: 43.160, -94.880

Hail, Kossuth

When: May 6, 4:17 PM CST
Where: Kossuth County, 2.13 mi NNW of Lotts Creek
Measured: 0.75 in hail
Reported by: Trained Spotter
Coordinates: 43.200, -94.380

Heavy Rain, Winnebago

When: May 6, 5:05 PM CST to 5:20 PM CST
Where: Winnebago County, 2.86 mi ESE of Rake
Reported by: Trained Spotter
Coordinates: 43.460, -93.880

One half inch of rain fell in 15 minutes.

Hail, Sac

When: May 6, 5:10 PM CST
Where: Sac County, 4.59 mi W of Sac City
Measured: 1 in hail
Property damage: $3,000
Reported by: Law Enforcement
Coordinates: 42.420, -95.090

Hail, Sac

When: May 6, 5:17 PM CST
Where: Sac County, Sac City
Measured: 1 in hail
Property damage: $3,000
Reported by: County Official
Coordinates: 42.420, -95.000

Hail reported to be dime to quarter size.

Hail, Sac

When: May 6, 5:19 PM CST
Where: Sac County, Sac City
Measured: 1 in hail
Property damage: $3,000
Reported by: Trained Spotter
Coordinates: 42.420, -95.000

Hail, Sac

When: May 6, 5:20 PM CST
Where: Sac County, Sac City
Measured: 0.75 in hail
Reported by: Trained Spotter
Coordinates: 42.420, -95.000

Two periods of hail occurred with the first lasting 30 to 45 seconds, the second was 2 minutes later and lasted 3-5 minutes. Hail covered the ground with half to three quarter inch hail.

Hail, Calhoun

When: May 6, 5:24 PM CST
Where: Calhoun County, 4.08 mi E of Jolley
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 42.480, -94.640

Hail, Calhoun

When: May 6, 5:35 PM CST
Where: Calhoun County, 2.13 mi NNE of Sherwood
Measured: 0.88 in hail
Reported by: County Official
Coordinates: 42.400, -94.710

Hail, Sac

When: May 6, 5:45 PM CST
Where: Sac County, 1.38 mi N of Sac City
Measured: 1 in hail
Property damage: $3,000
Reported by: Law Enforcement
Coordinates: 42.440, -95.000

Thunderstorm Wind, Cerro Gordo

When: May 6, 5:48 PM CST
Where: Cerro Gordo County, 3.6 mi NNW of (Mcw)mason City Muni
Measured: 57 kt (66 mph) estimated gust
Property damage: $25,000
Reported by: Law Enforcement
Coordinates: 43.200, -93.350

A semi-tractortrailer truck was blown over near mile post 197 on Interstate 35.

Thunderstorm Wind, Cerro Gordo

When: May 6, 5:49 PM CST
Where: Cerro Gordo County, 0.86 mi NW of (Mcw)mason City Muni
Measured: 57 kt (66 mph) measured gust
Property damage: $1,000
Reported by: ASOS
Coordinates: 43.160, -93.340

Hail, Calhoun

When: May 6, 5:54 PM CST
Where: Calhoun County, 2.07 mi N of Somers
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 42.410, -94.430

Thunderstorm Wind, Franklin

When: May 6, 6:17 PM CST
Where: Franklin County, 0.86 mi SE of Latimer
Measured: 53 kt (61 mph) measured gust
Property damage: $1,000
Reported by: Mesonet
Coordinates: 42.760, -93.360

Thunderstorm Wind, Franklin

When: May 6, 6:40 PM CST
Where: Franklin County, 3.62 mi W of Geneva
Measured: 52 kt (60 mph) estimated gust
Property damage: $1,000
Reported by: Trained Spotter
Coordinates: 42.670, -93.200

Six inch tree limbs were blown down on the highway.

Heavy Rain, Hardin

When: May 6, 6:45 PM CST to May 7, 1:15 AM CST
Where: Hardin County, 5.6 mi W of Iowa Falls
Property damage: $50,000
Reported by: Trained Spotter
Coordinates: 42.520, -93.380

The rain began around 1845 CST Tuesday evening and ended around 0115 CST Wednesday morning. A total of 6.25 inches was reported.

Thunderstorm Wind, Franklin

When: May 6, 6:45 PM CST
Where: Franklin County, Geneva
Measured: 52 kt (60 mph) estimated gust
Property damage: $5,000
Reported by: Trained Spotter
Coordinates: 42.680, -93.130

Large trees were blown down by 60 MPH winds.

Hail, Hamilton

When: May 6, 6:51 PM CST
Where: Hamilton County, 1.47 mi SSE of Jewell
Measured: 0.75 in hail
Reported by: Amateur Radio
Coordinates: 42.280, -93.640

Heavy Rain, Boone

When: May 6, 7:18 PM CST to 8:48 PM CST
Where: Boone County, 1.38 mi S of Boone
Property damage: $50,000
Reported by: Emergency Manager
Coordinates: 42.050, -93.880

Heavy rain of 3 inches caused basement flooding in Boone.

Hail, Boone

When: May 6, 7:29 PM CST
Where: Boone County, 1.38 mi S of Boone
Measured: 1 in hail
Property damage: $5,000
Reported by: Emergency Manager
Coordinates: 42.050, -93.880

Thunderstorm Wind, Bremer

When: May 6, 7:30 PM CST
Where: Bremer County, 1 mi S of Waverly
Measured: 57 kt (66 mph) estimated gust
Property damage: $50,000
Reported by: NWS Employee
Coordinates: 42.715, -92.480

Heavy Rain, Story

When: May 6, 7:42 PM CST to 8:42 PM CST
Where: Story County, 0.86 mi SW of Ames
Reported by: Trained Spotter
Coordinates: 42.020, -93.630

A trained spotter reported 1.6 inches of rain in the past hour.

Heavy Rain, Black Hawk

When: May 6, 7:53 PM CST to 8:08 PM CST
Where: Black Hawk County, Dewar
Reported by: Trained Spotter
Coordinates: 42.520, -92.220

One half inch of rain fell in 15 minutes.

Heavy Rain, Story

When: May 6, 8:00 PM CST to 9:28 PM CST
Where: Story County, 2.81 mi N of Ontario
Property damage: $10,000
Reported by: Trained Spotter
Coordinates: 42.070, -93.670

Rainfall of 2.73 inches was measured in Ames during the past hour and one half.

Flash Flood, Boone

When: May 6, 8:14 PM CST to 11:00 PM CST
Where: Boone County, 0.95 mi NNW of Sheldahl to 2.61 mi SSW of Berkley
Cause: Heavy Rain
Property damage: $25,000
Reported by: Emergency Manager
Coordinates: 41.883, -93.724

Six inches to one foot of water running over roads resulted in a number of road closures in Boone County.

Flash Flood, Wright

When: May 6, 11:30 PM CST to May 7, 2:00 AM CST
Where: Wright County, 4.65 mi S of Clarion Arpt to 3.74 mi NE of Woolstock
Cause: Heavy Rain
Property damage: $25,000
Reported by: Law Enforcement
Coordinates: 42.663, -93.759

A portion of County Road R38 had water over the road near the intersection of R38 and 280th St. There were also reports of water over County Road C54. Flooding was also reported near the intersection of 290th and Madison, and also at 200th and Calhoun.

Flash Flood, Hardin

When: May 6, 11:34 PM CST to May 7, 2:00 AM CST
Where: Hardin County, 3.42 mi WNW of Iowa Falls Muni Arpt to 2.64 mi SE of Alden
Cause: Heavy Rain
Property damage: $25,000
Reported by: Law Enforcement
Coordinates: 42.484, -93.334

Twelve inches of water was flowing over County Road D20, or old Highway 20, at the 18,000 block.

Flood, Hardin

When: May 7, 1:30 AM CST to 10:17 AM CST
Where: Hardin County, 4.04 mi WSW of Iowa Falls to 5.96 mi W of Iowa Falls
Cause: Heavy Rain
Property damage: $75,000
Reported by: County Official
Coordinates: 42.506, -93.347

The Mayor of Alden reported that the Alden Elementary School was closed Wednesday due to 4 feet of water in the boiler room and a foot of water in the cafeteria. The water softener, main compressor, and several chemicals have water damage in the boiler room as well.

Flood, Hardin

When: May 7, 5:28 AM CST to 10:17 AM CST
Where: Hardin County, 4.64 mi W of Iowa Falls to 1.06 mi W of Iowa Falls
Cause: Heavy Rain
Property damage: $25,000
Reported by: Law Enforcement
Coordinates: 42.510, -93.360

The Hardin County Sheriff reported the intersection of D15 and D20 closed between Iowa Falls and Alden.

Flood, Hardin

When: May 7, 5:36 AM CST to 10:17 AM CST
Where: Hardin County, 4.36 mi W of Iowa Falls to 6.27 mi WNW of Iowa Falls
Cause: Heavy Rain
Property damage: $50,000
Reported by: County Official
Coordinates: 42.509, -93.354

The Mayor of Alden reported that several County Roads were washed out or covered with water in and around Alden. The Alden Fire Department was pumping water out of drains due to storm drains running full and manhole covers popping.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
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.
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.
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

Every storm in Iowa in 2008 Every state in 2008 This day in weather history Warnings in Iowa, May 2008

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: 86289, 86290, 86291, 86292, 86293, 86305, 86298, 86294, 86295, 86296, 86297, 86299, 86301, 86314, 86319, 86302, 86321, 86315, 86312, 86317, 86303, 86308, 86304, 86905, 86307, 86306, 86309, 86281, 86283, 86285, 86286, 86287, 86288.