Hail in Iowa, July 31, 2003

Name: Hail in Iowa, July 31, 2003
Start: 2003-07-31T16:07
End: 2003-07-31T23:25
Location: Iowa

July 31, 2003 · NWS DMX · 18 events in 7 counties and zones

An unstable airmass was in place over Iowa during the day on the 31st, though not as unstable as was the case during the first part of the month. Lifted indices were as low as -8 to -10 C.

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: $216,000
Crop damage: $332,000
Events: 18

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.

An unstable airmass was in place over Iowa during the day on the 31st, though not as unstable as was the case during the first part of the month. Lifted indices were as low as -8 to -10 C. during the late afternoon hours over northeast Iowa with CAPE values in the 2000 to 3000 J/kg range. Dew points were in the mid 60s to near 70 through the afternoon into the evening hours with a narrow ribbon of moisture feeding into northeast and north central Iowa through the afternoon and evening hours. Thunderstorms fired during the afternoon, mainly northeast of the Des Moines CWA. One storm developed in Black Hawk County and dropped golf ball size hail in the town of Dunkerton. The weather was fairly quiet during the early evening as a cold front approached from the northwest. Thunderstorms developed ahead of the front as the area of convection to the northeast of Iowa developed westward into north central Iowa. The storms produced hail in several counties. With freezing levels relatively low, at around 12,000 feet, some of the hail became quite large. In Cerro Gordo County, hail from golf ball up to baseball size was reported in the Rockwell area. The hail caused considerable damage. In addition, several head of sheep were killed by the large hail on a farm near Rockwell. In Butler, quarter to baseball size hail pelted the area. The hail covered the ground in places resulting in near total destruction of crops south of the Dumont area.

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 Jul 31, 2:05 PM CST, 2 hours 2 minutes earlier.

Area forecast discussion, Jul 31, 2:05 PM CST, 2 hours 2 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
305 PM CDT THU JUL 31 2003

STTN WITH CDFNT DVLPG ABT AS SELS INDICTD IN LATEST SWODY1 AND WUD
NOT BE SURPRISED TO SEE SLGT AREA BKN INTO TWO WITH IA SPLIT OUT FOT
THE MOST PART IN NXT UPDT.  BEST SHOT OVR NERN IA AND WL CARRY LKLY
POPS IN CUR WATCH AREA.  CHC ELSW, BUT XPCT PCPN MST ACTVTY TO ONLY
BRUSH SWRN ZNS.  SYS DPCTD INIT ON 06Z CHTS WL BRUSH SRN IA FRI.
ONLY OTR PCPN IN FCST WL BE CYC CRCLN AFTN SHWRS OVR THE NERN ZNS.
IA CAUGHT IN BLOCK AFT THAT THRU DAY 7 WITH TEMPS MODERATING SLOWLY
AND NO SIG WX.  SHAVED TEMPS THUT FCST A FEW DEG WITH ALL MDLS
SHOWING COLDER AIR WORKING IN ARND UPR LO.

.DSM...NONE

Hazardous weather outlook, Jul 31, 11:05 AM CST, 5 hours 2 minutes before

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-011100-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1205 PM CDT THU JUL 31 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

A COLD FRONT WILL PUSH ACROSS CENTRAL IOWA THIS AFTERNOON AND
TONIGHT.  THUNDERSTORMS ARE FORECAST TO DEVELOP ALONG AND AHEAD OF
THIS FRONT AFTER NOON.  A FEW STORMS MAY BECOME SEVERE THIS
AFTERNOON AND EVENING.  LARGE HAIL AND DAMAGING WIND WILL BE THE
MAIN THREAT.  THE POTENTIAL DOES EXIST FOR AN ISOLATED SUPERCELL
THUNDERSTORM THAT COULD PRODUCE A TORNADO...MAINLY EAST OF I-35.
ADDITIONAL THUNDERSTORMS ARE POSSIBLE DURING THE OVERNIGHT HOURS BUT
THE SEVERE POTENTIAL WILL DIMINISH AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A LARGE AREA OF LOW PRESSURE NEAR THE MINNESOTA AND CANADIAN BORDER
WILL SINK INTO WISCONSIN FRIDAY WHERE IT WILL MOVE VERY LITTLE FOR
THE NEXT THREE DAYS.  DISTURBANCES ROTATING AROUND THIS LOW WILL
BRING ADDITIONAL CHANCES FOR THUNDERSTORMS ON FRIDAY ACROSS THE
SOUTHEAST PORTION OF CENTRAL IOWA.  ON SATURDAY YET ANOTHER
DISTURBANCE WILL BRING A CHANCE FOR THUNDERSTORMS TO NORTHEAST PARTS
OF CENTRAL IOWA.  TIMING DETAILS ARE NOT CLEAR THOUGH THE AFTERNOON
AND EVENING HOURS APPEAR TO BE THE BEST TIME FOR THE DEVELOPMENT OF
THE STORMS FOR FRIDAY AND SATURDAY.  LARGE HAIL AND DAMAGING WIND
WOULD BE THE MAIN THREATS FROM THESE STORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE THIS AFTERNOON THROUGH MIDNIGHT.
SPOTTERS MAY ONCE AGAIN BE NEEDED FRIDAY AFTERNOON MAINLY EAST OF
I-35 AND SOUTH OF HIGHWAY 20.
&&

MORE INFORMATION CAN BE OBTAINED AT WWW.CRH.NOAA.GOV/DMX (ALL LOWER
CASE).

FORSTER

The radar

The Des Moines radar (KDMX), 158 km away, was scanning. The volume nearest the first event began at 22:06 UTC.

Open the radar archive at this moment

Event by event

18 hail. Local standard time, as filed.

Hail, Black Hawk

When: July 31, 4:07 PM CST
Where: Black Hawk County, Dunkerton
Measured: 1.75 in hail
Property damage: $25,000
Crop damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 42.567, -92.167

Hail, Cerro Gordo

When: July 31, 9:20 PM CST
Where: Cerro Gordo County, 5 mi NNE of Clear Lake
Measured: 1 in hail
Property damage: $5,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 43.200, -93.350

Hail, Palo Alto

When: July 31, 9:30 PM CST
Where: Palo Alto County, 4 mi E of Mallard
Measured: 0.75 in hail
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.933, -94.600

Hail, Cerro Gordo

When: July 31, 9:32 PM CST
Where: Cerro Gordo County, Mason City
Measured: 1.75 in hail
Property damage: $25,000
Crop damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.150, -93.200

Hail, Pocahontas

When: July 31, 9:39 PM CST
Where: Pocahontas County, 2 mi N of Plover
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.917, -94.633

Hail, Pocahontas

When: July 31, 9:46 PM CST
Where: Pocahontas County, Plover
Measured: 0.88 in hail
Property damage: $3,000
Crop damage: $2,000
Reported by: UNKNOWN
Coordinates: 42.883, -94.633

Hail, Cerro Gordo

When: July 31, 9:55 PM CST
Where: Cerro Gordo County, Rockwell
Measured: 1.75 in hail
Property damage: $20,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.983, -93.183

Hail, Cerro Gordo

When: July 31, 9:58 PM CST
Where: Cerro Gordo County, Rockwell
Measured: 2.5 in hail
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.983, -93.183

Hail, Cerro Gordo

When: July 31, 10:00 PM CST
Where: Cerro Gordo County, Rockwell
Measured: 1.75 in hail
Property damage: $20,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.983, -93.183

Hail, Pocahontas

When: July 31, 10:00 PM CST
Where: Pocahontas County, Rolfe
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.817, -94.517

Hail, Cerro Gordo

When: July 31, 10:00 PM CST
Where: Cerro Gordo County, Rockwell
Measured: 2.75 in hail
Property damage: $25,000
Crop damage: $25,000
Reported by: UNKNOWN
Coordinates: 42.983, -93.183

Hail, Hancock

When: July 31, 10:10 PM CST
Where: Hancock County, 1 mi E of Garner
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: NWS EMPLOYEE(OFF DUTY)
Coordinates: 43.100, -93.600

Hail, Butler

When: July 31, 10:46 PM CST
Where: Butler County, Dumont
Measured: 1 in hail
Property damage: $5,000
Crop damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 42.750, -92.967

Hail, Butler

When: July 31, 10:51 PM CST
Where: Butler County, Dumont
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 42.750, -92.967

Hail, Butler

When: July 31, 10:55 PM CST
Where: Butler County, Dumont
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 42.750, -92.967

Hail, Butler

When: July 31, 10:57 PM CST
Where: Butler County, 2 mi S of Dumont
Measured: 2.75 in hail
Property damage: $25,000
Crop damage: $200,000
Reported by: NEWSPAPER
Coordinates: 42.717, -92.967

Hail, Franklin

When: July 31, 11:02 PM CST
Where: Franklin County, 6 mi N of Hampton
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 42.833, -93.200

Hail, Franklin

When: July 31, 11:25 PM CST
Where: Franklin County, 15 mi NW of Hampton
Measured: 0.88 in hail
Property damage: $1,000
Crop damage: $5,000
Reported by: GENERAL PUBLIC
Coordinates: 42.900, -93.417

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

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

The same day elsewhere

Every storm in Iowa in 2003 Every state in 2003 This day in weather history Warnings in Iowa, July 2003

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: 5367284, 5367285, 5367286, 5367287, 5367288, 5367289, 5367290, 5367291, 5367292, 5367293, 5367294, 5367295, 5367296, 5367297, 5367298, 5367301, 5367299, 5367300.