Iowa, 2003

Tornadoes and Hail in Iowa, May 10, 2003

May 10, 2003 · NWS DMX · 22 events in 10 counties and zones

A very intense spring storm system developed over the central Plains and moved east, then northeast across Kansas into eastern Iowa. The low deepened to 986 mb by 06z of the 11th as it passed over La Crosse, WI.

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
$356,000
Crop damage
None recorded
Events
22

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 intense spring storm system developed over the central Plains and moved east, then northeast across Kansas into eastern Iowa. The low deepened to 986 mb by 06z of the 11th as it passed over La Crosse, WI. A southerly low level jet of 40 to 55 kts developed ahead of the storm system. A warm front extended east from the low and served as a focusing point for thunderstorm development early on, while a dry line extended south from the low lead to the development of a line of severe thunderstorms. Dew point temperatures in the warm sector soared into the upper 60s to mid 70s with temperature readings in the 80s. Dew point values at the 850 mb level were in the 14 to 17 degree C. range. By mid day, CAPE values over eastern KS into western MO were around 5000 J/kg with lifted indices around -11 C. Thunderstorms developed explosively by the mid afternoon hours. For the most part, severe weather from the storms in Iowa was in the form of Hail as most of the activity was north of the warm front. Parts of central into northeast Iowa received golf ball to larger than baseball size hail. The hardest hit area was in Poweshiek County in the Grinnell area, where 3 inch diameter hail caused considerable damage. There were scattered reports of nickel to ping pong ball size hail from Interstate 35 east. A few tornadoes occurred close to the triple point of the storm system. One tornado touched down in Marion County southwest of Attica and moved into Mahaska County northwest of Leighton. The track was generally through open countryside with little damage reported. One trailer was overturned east of Columbia near the beginning of the intermittent track of the tornado. Another brief touchdown was reported in Tama County near Clutier. No damage was reported with this tornado.

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 10, 1:58 PM CST, 54 minutes earlier.

Area forecast discussion, May 10, 1:58 PM CST, 54 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
258 PM CDT SAT MAY 10 2003

SVRL SGFNT THINGS TO CONSIDER TDA FM SVR WX TO HIGH WND POTENTIAL.
STLT IMAGERY SHOWS LG WV TROF THRU HIGH PLAINS WITH SHRT WV/SHEAR
AXIS FM KS/NE INTO MO VLY.  20Z SFC ANLYS PLACES LOW/TRIPLE POINT
JUST N KMKC METRO AREA WITH OLD OUTFLOW BNDRY TO JUST S KSTL METRO
AND ASSOCD WRMFNT INTO IA ALG KLWD-KCWI LN.  ELEVATED INSTABLITY
AXIS INTO S CNTRL IA WITH MLCAPES AOA 1000 J/KG HEADING INTO SERN IA
AS WRM SECTOR SURGES NWD.  DEEP LAYER SHEAR STG WITH VARIOUS
SUPERCELL/TORNADO SCREAMING...BUT MAINLY S ACRS MO AT THIS
POINT.  PRIMARY WARM SECTOR LOOKS TO BE ASSOCD WITH OUTFLOW BNDRY
WITH EXTRAPOLATION OF CURRENT FEATURES GOING ACRS SERN IA AND OUT OF
FA ARND 23Z.  FAVORED AREA FOR TORNADIC SUPERCELLS WOULD APPR TO BE
ALG AND SE OF KLWD-KPEA-JUST S KALO LN.  MAY SEE HAIL POTENTIAL IN
ELEVATED CONVECTION IN DEFORMATION ZN TOO.  HGT FALL CNTR AND STG
KINEMATIC FORCING CROSSES SRN 2/3RD OF FA THIS EVE.  SYS SHOULD BE
FAST MOVG ENOUGH THAT RAINS MAY BE LCLLY HVY BUT BRIEF ENOUGH TO NOT
AGGREVATE FLOODING SITUATION MUCH.  WL GO WITH CATEGORICAL WORDING
NWRN THIRD...CHCS SW...AND LIKELY CNTRL TO SE.  PCPN SHOULD DMSH
OVNGT TO CHC CATEGORY NERN PTNS.

NEXT QUESTION WL BE WNDS LATE TNGT AND SUN.  SFC LOW SHOULD QUICKLY
LIFT INTO KLSE VCNTY TWRD 06Z.  STG HGT FALL CNTR SHOULD DEEPING SFC
LOW WITH PRODUCE SGFNT ISALLOBARIC COUPLET AS DEPICTED BY MDLS.
THIS AND FOLLOWING PRES RISE CNTR SHOULD EXIT FA BY 12Z...WITH
SCNDRY ISALLOBARIC MAX INTO NERN SXNS TMRW.  PRES GRADIENT QUITE
IMPRESSIVE SO HAVE ISSUED WND ADVY LATE TNGT AND SUN FOR NRN 2 TO 3
TIERS OF COUNTIES.  TEMP WISE GENERALLY FOLLOWED COMPROMISE OF
GUIDANCE WHICH IS FAIRLY CLOSE.

PRIMARY QUESTIONS FOR NEXT WEEK WL BE POPS WITH MIDWEEK SYS...AND
WHETHER TO ADD MENTION AGN LATE IN WEEK.  RECENT GFS RUNS STRONGEST
WITH SYS ARND WED...EURO MDLS WEAKEST AND CANADIAN A COMPROMISE.
GFS SLOWEST WITH EURO/CANADIAN SOLUTIONS A BIT FASTER.  HWVR 12Z GFS
AND GFS ENSEMBLES ARE LEANING IN DIRECTION OF CANADIAN/EURO MDLS.
SEE NO REASON TO ALTER NCEP THINKING OF FOLLOWING ECMWF...SPCLLY
ARND MIDWEEK...WITH INFLUENCE OF 12Z GFS AND ENSEMBLES IN LATER PDS
TOO.  THUS WL KEEP CHCS GOING TUE NGT WRN PTNS...AND FA WIDE WED.
TWRD FRI AND SAT...ECMWF MUCH STGR AND FARTHER N WITH SRN PLAINS
SYS.  HWVR WL SIDE WITH SUGGESTIONS FM GFS/CANADIAN ENSEMBLES AND
SURROUNDING OFFICES KEEPING FCST DRY ATTM.  DO NOT HAVE THE BEST
CONFIDENCE IN 00Z MOS EITHER SO HAVE NOT CHGD GOING TEMPS MUCH.

.DSM...WND ADVY OVNGT AND SUN NRN PTNS
       IAZ004>007-015>017-024>028

SMALL
Hazardous weather outlook, May 10, 10:50 AM CST, 4 hours 2 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-111100-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1150 AM CDT SAT MAY 10 2003

...MORE SEVERE WEATHER POSSIBLE THIS AFTERNOON AND EARLY EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A SURFACE LOW WILL TRACK THROUGH SOUTHEAST IOWA...AND DRAW VERY
MOIST...UNSTABLE AIR INTO THE SOUTHERN PART OF THE STATE THIS
AFTERNOON INTO THE EARLY EVENING HOURS. SUPERCELL THUNDERSTORMS WITH
SEVERE WEATHER ARE POSSIBLE FROM AROUND 3 PM TO 9 PM.  THE AREA IN
HIGH RISK FOR SEEING SEVERE WEATHER LIES SOUTHEAST OF A LINE FROM
EDDYVILLE TO CLIO.  LARGE HAIL...DAMAGING WIND AND TORNADOES ARE
POSSIBLE IN THIS AREA.  THERE IS A MODERATE RISK OF SEVERE STORMS
SOUTHEAST OF A LINE FROM BROOKLYN TO LAMONI. LARGE HAIL...DAMAGING
WIND AND ISOLATED TORNADOES ARE POSSIBLE IN THIS AREA. IN
ADDITION...RAINFALL AMOUNTS OF A QUARTER TO ONE HALF INCH ARE
POSSIBLE OVER CENTRAL IOWA THROUGH TONIGHT...WITH ISOLATED TOTALS
BETWEEN 1 AND 2 INCHES. LOCALLY HEAVY RAIN WILL HAVE AN AFFECT ON
AREA RIVERS DURING THE COMING WEEK...BUT THE RISK FOR FLASH FLOODING
IS LOW FOR TODAY AND TONIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

EXPECT VERY WINDY CONDITIONS ON SUNDAY...WITH A SUSTAINED NORTHWEST
WIND AT 20 TO 30 MPH...AND GUSTS TO 45 MPH. PERIODS OF SHOWERS AND A
FEW THUNDERSTORMS ARE EXPECTED ACROSS PARTS OF CENTRAL IOWA TUESDAY
NIGHT INTO WEDNESDAY...AND AGAIN THURSDAY. NO SEVERE WEATHER IS
ANTICIPATED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY THIS AFTERNOON INTO EARLY
EVENING...MAINLY ALONG AND SOUTHEAST OF A LINE FROM BROOKLYN TO
LAMONI.
&&

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

FAB

The radar

The Des Moines radar (KDMX), 126 km away, was scanning. The volume nearest the first event began at 20:53 UTC.

Open the radar archive at this moment

Event by event

19 hail, 3 tornado. Local standard time, as filed.

Hail, Franklin

When
May 10, 2:52 PM CST
Where
Franklin County, 3 mi N of Alexander
Measured
1 in hail
Property damage
$3,000
Reported by
TRAINED SPOTTER
Coordinates
42.850, -93.467

Hail, Cerro Gordo

When
May 10, 2:54 PM CST
Where
Cerro Gordo County, Thornton
Measured
1.75 in hail
Property damage
$15,000
Reported by
BROADCAST MEDIA
Coordinates
42.950, -93.383

Hail, Cerro Gordo

When
May 10, 3:11 PM CST
Where
Cerro Gordo County, 4 mi NW of Thornton
Measured
1 in hail
Property damage
$5,000
Reported by
TRAINED SPOTTER
Coordinates
42.983, -93.433

Hail, Butler

When
May 10, 3:44 PM CST
Where
Butler County, Clarksville
Measured
0.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
42.783, -92.667

Hail, Tama

When
May 10, 4:06 PM CST
Where
Tama County, 4 mi NE of Chelsea
Measured
1 in hail
Property damage
$5,000
Reported by
STORM CHASER
Coordinates
41.950, -92.350

Hail, Marion

When
May 10, 4:20 PM CST
Where
Marion County, 10 mi N of Knoxville
Measured
1 in hail
Property damage
$5,000
Reported by
UNKNOWN
Coordinates
41.467, -93.100

Hail, Marion

When
May 10, 4:25 PM CST
Where
Marion County, 4 mi NW of Pella
Measured
1.5 in hail
Property damage
$10,000
Reported by
BROADCAST MEDIA
Coordinates
41.450, -92.983

Tornado, Marion

When
May 10, 4:26 PM CST to 4:55 PM CST
Where
Marion County, 2 mi E of Columbia
Rating
F1
Path length
15 mi
Path width
50 yd
Property damage
$30,000
Reported by
LAW ENFORCEMENT
Coordinates
41.183, -93.117

Moved in rural area northeast into Mahaska County. Tornado had intermittent track.

Hail, Davis

When
May 10, 4:40 PM CST
Where
Davis County, 3 mi SW of Paris
Measured
1 in hail
Property damage
$3,000
Reported by
TRAINED SPOTTER
Coordinates
40.750, -92.600

Hail, Mahaska

When
May 10, 4:40 PM CST
Where
Mahaska County, 3 mi NW of Peoria
Measured
2.5 in hail
Property damage
$20,000
Reported by
BROADCAST MEDIA
Coordinates
41.500, -92.833

Hail, Poweshiek

When
May 10, 4:40 PM CST
Where
Poweshiek County, Grinnell
Measured
2 in hail
Property damage
$50,000
Reported by
TRAINED SPOTTER
Coordinates
41.750, -92.733

Hail, Poweshiek

When
May 10, 4:40 PM CST
Where
Poweshiek County, Grinnell
Measured
1.75 in hail
Property damage
$15,000
Reported by
TRAINED SPOTTER
Coordinates
41.750, -92.733

Hail, Poweshiek

When
May 10, 4:42 PM CST
Where
Poweshiek County, Grinnell
Measured
1.75 in hail
Property damage
$15,000
Reported by
TRAINED SPOTTER
Coordinates
41.750, -92.733

Hail, Poweshiek

When
May 10, 4:45 PM CST
Where
Poweshiek County, Grinnell
Measured
2.75 in hail
Property damage
$50,000
Reported by
TRAINED SPOTTER
Coordinates
41.750, -92.733

Hail, Poweshiek

When
May 10, 4:47 PM CST
Where
Poweshiek County, Grinnell
Measured
1.75 in hail
Property damage
$15,000
Reported by
TRAINED SPOTTER
Coordinates
41.750, -92.733

Hail, Poweshiek

When
May 10, 4:50 PM CST
Where
Poweshiek County, Grinnell
Measured
3 in hail
Property damage
$50,000
Reported by
BROADCAST MEDIA
Coordinates
41.750, -92.733

Hail, Poweshiek

When
May 10, 4:50 PM CST
Where
Poweshiek County, Grinnell Arpt
Measured
2.5 in hail
Property damage
$50,000
Reported by
BROADCAST MEDIA
Coordinates
41.717, -92.700

Tornado, Mahaska

When
May 10, 4:55 PM CST to 5:02 PM CST
Where
Mahaska County, 5 mi WSW of Leighton
Rating
F1
Path length
3.5 mi
Path width
40 yd
Property damage
$2,000
Reported by
BROADCAST MEDIA
Coordinates
41.317, -92.883

Moved from Marion County into rural Mahaska County.

Tornado, Tama

When
May 10, 5:27 PM CST
Where
Tama County, Clutier
Rating
F0
Path length
0.1 mi
Path width
25 yd
Reported by
EMERGENCY MANAGER
Coordinates
42.083, -92.400

Brief touchdown in open area.

Hail, Black Hawk

When
May 10, 5:49 PM CST
Where
Black Hawk County, 1 mi NW of Dunkerton
Measured
1 in hail
Property damage
$3,000
Reported by
TRAINED SPOTTER
Coordinates
42.583, -92.183

Hail, Bremer

When
May 10, 5:55 PM CST
Where
Bremer County, 3 mi SE of Readlyn
Measured
0.75 in hail
Reported by
GENERAL PUBLIC
Coordinates
42.667, -92.183

Hail, Bremer

When
May 10, 6:10 PM CST
Where
Bremer County, Waverly
Measured
1.75 in hail
Property damage
$10,000
Reported by
BROADCAST MEDIA
Coordinates
42.733, -92.483

What these are

Hail
Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Tornado
A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.

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

The same day elsewhere

More

Every storm in Iowa in 2003Every state in 2003This day in weather historyThe tornado archive for Iowa, 2003Warnings in Iowa, May 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: 5352314, 5352303, 5352304, 5352311, 5352302, 5351353, 5351354, 5351358, 5351355, 5351356, 5351357, 5352306, 5352305, 5351360, 5351462, 5352307, 5352308, 5351359, 5352309, 5352313, 5352310, 5352312.