A very unstable airmass was in place over western Iowa and areas to the west. CAPE rose to over 6500 J/kg by late afternoon with the lifted indices falling to -12 to -15 C.
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.
A very unstable airmass was in place over western Iowa and areas to the west. CAPE rose to over 6500 J/kg by late afternoon with the lifted indices falling to -12 to -15 C. Downdraft CAPE as quite high at around 1600 J/kg, while available CAPE in the -10 to -30 C layer of the atmosphere was between 700 and 1000 J/kg. The atmosphere had a strong shear present with 40 to 60 kts The freezing level was quite high, just below 15,000 feet. Precipitable water increased to around 1.5 inches. Strong thunderstorms developed over southern Minnesota. Initially, the thunderstorms moved east. Once they became more rooted in the boundary layer, they moved southeast and propagated nearly due south. The main severe threat was high winds, with numerous reports of tree, power line, and grain bin damage. Winds of 70 MPH were measured in Estherville for example. Seventy MPH winds were reported in Grundy County. The outflow boundary from the complex continued to move southeast, and actually moved all the way into Missouri. Scattered severe weather occurred with this. Seven power poles were snapped in Polk County by the high winds. A wind gust of 62 MPH occurred at the Ottumwa Airport. Flash flooding also became a problem with the antecedent soil conditions nearly saturated. Flash flooding in Emmet County resulted in the closing of Highway 4 near Wallingford and evacuations in the city. A secondary area of thunderstorms formed over northwest Iowa and moved east-southeast into the CWA. Heavy rains caused minor urban flooding in Calhoun County with 6 inches of standing water reported in the city of Pomeroy. Although many of the storms produced small hail, there were very few reports of hail larger than dime size. Reports of hail up to an inch in diameter were received in central Iowa late in the evolution of the system. Lightning struck a house east of Grinnell during the early morning hours around 0330 CST. The house was set on fire with structural damage and damage to contents estimated at $550,000.
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 Jun 25, 5:35 PM CST, 2 hours 10 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 635 PM CDT FRI JUN 25 2010 .SHORT TERM /TODAY/... FORECAST FOR TONIGHT IS HEAVILY DICTATED BY CONVECTIVE EVOLUTION OF THUNDERSTORMS EXPECTED TO DEVELOP TO OUR NORTH LATER THIS AFTERNOON. A WEAK SURFACE LOW IS DRIFTING SLOWLY EASTWARD BETWEEN PIERRE AND ABERDEEN...WITH A STATIONARY SURFACE BOUNDARY EXTENDING ENE ACROSS SOUTHERN/CENTRAL MN OVER INTO NW WISC. A MID-LEVEL SHORTWAVE IS APPROACHING THESE AREAS FROM THE WEST WHILE IN THE LOWER LEVELS SOUTHERLY FLOW IS LEADING TO RAPID DESTABILIZATION ACROSS THE REGION SOUTH OF THE AFOREMENTIONED BOUNDARY. 70S SFC DEWPTS HAVE SURGED FROM SOUTHERN KS EARLIER THIS MORNING INTO THE IA/SDAK/MN REGION AS OF EARLY THIS AFTERNOON. HOWEVER...STRONG CAPPING REMAINS IN PLACE ACROSS OUR AREA WITH CU FIELD/STORM DEVELOPMENT CURRENTLY LIMITED TO AREAS NEAR THE BOUNDARY WELL TO OUR NORTH. EXPECT THAT LATER THIS AFTERNOON AS THE SHORTWAVE APPROACHES THE CAP WILL WEAKEN AND STORMS WILL DEVELOP RAPIDLY FROM EASTERN SDAK INTO MN. INITIALLY THIS CONVECTION SHOULD MOVE EAST OR ESE IN THE MEAN FLOW BUT THEN EXPECT IT WILL TURN MORE SE TOWARD THE GREATER INSTABILITY THIS EVENING INTO TONIGHT. SPC IS MAINTAINING A SLIGHT RISK OF SEVERE WEATHER ACROSS ABOUT OUR NORTHERN HALF WITH A MODERATE RISK IN OUR FAR NORTHERN TIER OR TWO OF COUNTIES. HAVE UPDATED POPS TONIGHT TO REFLECT THINKING ABOVE AND HAVE INCLUDED SEVERE WORDING ROUGHLY ALONG/NORTH OF HWY 20 THIS EVENING AS FURTHER SOUTH THE POTENTIAL APPEARS LIMITED BY WEAKER BULK SHEAR AND A LIKELY LATER ARRIVAL TIME. THERE IS STILL CONSIDERABLE UNCERTAINTY REGARDING HOW FAR SOUTH THE STORMS WILL PENETRATE OUR AREA...BUT IT APPEARS INCREASINGLY LIKELY THAT AREAS FROM AROUND CLARION TO MARSHALLTOWN TO TAMA COULD SEE SOME STORMS IF THEY DO INDEED MAKE THAT TURN TO THE SOUTHEAST. TIMING OF THE STORMS IS ALSO DIFFICULT TO DETERMINE AT THIS TIME BUT MOST LIKELY WINDOW APPEARS TO BE FROM AROUND 00Z IN OUR FAR N/NW TO AROUND 06Z IN OUR E/NE. OTHER THAN CONVECTIVE ELEMENTS FEW CHANGES MADE TO GRIDS/FORECAST FOR TONIGHT. .LONG TERM /TONIGHT THROUGH TUESDAY/... SHORT TERM HRRR/WRF/NAM SUGGEST QUIET SATURDAY MORNING BEHIND CONVECTIVE SYSTEM TONIGHT AND HAVE KEPT POPS NIL BEFORE MIDDAY. WILL SEE INSTABILITY INCREASE RAPIDLY BY AFTERNOON WITH DEEP LAYER SHEAR BEST IN NORTHERN IA CLOSEST TO THE WESTERLIES. ANTICIPATE INITIAL DEVELOPMENT NEAR THE IA/MN BORDER BY LATE AFTERNOON WITH ALL MODES OF SEVERE WEATHER POSSIBLE AT THAT TIME. SOME CONCERN WITH HYDRO AS WELL AS FORCING WILL CONTINUE IN THAT AREA THROUGH THE NIGHT WITH MODERATE LOW LEVEL FLOW POINTING INTO THE STATE. NOT UNTIL THE FRONT/SHORT WAVE ARRIVE EARLY SUNDAY MORNING WILL THE PCPN MOVE IN BODY ACRS THE STATE AND OUT OF IA ON SUNDAY. THEREAFTER... LARGE EASTERN TROF DEVELOPS WITH QUIET WEATHER PERSISTING THROUGH MUCH OF THE WORK WEEK. APPEARS THAT 850MB FLOW WILL BE FROM THE NORTHEAST WITH RELATIVELY COOL TEMPERATURES INTO NEXT WEEK ALONG WITH THE CALM WEATHER. NOT UNTIL LATE IN THE WEEK AND THE 4TH OF JULY WEEKEND DOES IT APPEAR THAT IA WILL HAVE CHANCES OF PCPN. && .AVIATION... 26/00Z...DEVELOPING TSRA COMPLEX OVR SRN MN WILL SPRD/DVLP SWD INT NRN IA AND TRIED TO TIME A COUPLE HR PD OF GREATEST THREAT ACRS THE TAF SITES. THINKING NOW IS KFOD 03Z, KALO 05Z KMCW 03Z, KDSM 06Z, AND KOTM 08Z. WILL CARRY A HR OR TWO WINDOW ARND OF VCTS TYPE STUFF...BUT EXPECT CONDS OUTSIDE OF STRONG LINE TO BE VRR. VFR CONDS THRU A GOOD PART OF STA..BUT EXPECT TO SEE VIGEROUS TSRA DVLPT BY MID TO LATE AFTN OVR AT LEAST THE N HLF OF IA. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...LEE AVIATION...MS JUN 10 LONG TERM...COGIL
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 338 PM CDT FRI JUN 25 2010 IAZ033-034-044>049-057>062-070>075-081>086-092>097-261100- SAC-CALHOUN-CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-AUDUBON- GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN- MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR- RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS- 338 PM CDT FRI JUN 25 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT THERE IS A CHANCE OF THUNDERSTORMS FROM THIS EVENING THROUGH TONIGHT. THE BEST CHANCES WILL BE FURTHER NORTHEAST...WITH ISOLATED SEVERE THUNDERSTORMS AND LOCALLY HEAVY RAIN POSSIBLE MAINLY NORTH OF HIGHWAY 30. THE PRIMARY SEVERE WEATHER THREAT WILL BE STRONG WINDS. RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR PORTIONS OF THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY ADDITIONAL THUNDERSTORM CHANCES ARE FORECAST FROM SATURDAY EVENING INTO SUNDAY. SOME STORMS COULD BE SEVERE DURING THIS PERIOD. RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND POSSIBLY SATURDAY AFTERNOON AND NIGHT. IAZ004>007-015>017-023>028-035>039-050-261100- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-WEBSTER-HAMILTON- HARDIN-GRUNDY-BLACK HAWK-TAMA- 338 PM CDT FRI JUN 25 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...THIS AFTERNOON AND TONIGHT THUNDERSTORMS ARE EXPECTED TO MOVE INTO THE AREA THIS EVENING AND EARLY TONIGHT...WITH SEVERE WEATHER AND LOCALLY HEAVY RAIN LIKELY. THE GREATEST SEVERE WEATHER THREAT WILL BE FOR STRONG DAMAGING WINDS...HOWEVER LARGE HAIL AND ISOLATED TORNADOES ARE ALSO POSSIBLE. IN ADDITION...SOME AREAS ARE STILL SATURATED FROM HEAVY RAINS EARLIER THIS WEEK AND ANY ADDITIONAL HEAVY RAINFALL COULD LEAD TO MORE FLOODING. RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR PORTIONS OF THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY ADDITIONAL THUNDERSTORM CHANCES ARE FORECAST FROM SATURDAY AFTERNOON INTO SUNDAY. SOME STORMS COULD BE SEVERE DURING THIS PERIOD. RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING AND TONIGHT AND POSSIBLY SATURDAY AFTERNOON AND NIGHT. LEE
The Minneapolis radar (KMPX), 156 km away, was scanning. The volume nearest the first event began at 01:44 UTC.
23 thunderstorm wind, 5 heavy rain, 3 flash flood, 2 hail, 1 lightning, 1 flood. Local standard time, as filed.
Numerous 2 to 4 inch branches down.
Trees down in Lake Mills.
Tree down over highway 105.
Numerous trees down in Dolliver.
Grain bin down and blown into ditch.
Very strong wind kicking up debris. Potential wall cloud observed.
Trained spotter reports wind gusts in excess of 60 MPH. Power out in Dows.
Several trees down in town.
Five evergreen trees 18 to 24 inches in diameter were uprooted. Also 2 trees were uprooted on the northwest edge of Dows.
Several trees blown down.
Livestock trailer blown across the road into a ditch at 45th St east of Dogwood Ave.
Grain bin destroyed and laying in field along 50th Street.
Tree damage with power outages in the area.
Local law enforcement reports 70 MPH wind 3 miles south of the Butler County line 6 miles east of the Hardin County line.
Five inch diameter tree limbs snapped.
Wind estimated at nearly 60 MPH.
The Wright County Sheriffs office reported highway 3 east and west of Clarion beginning to flood, along with county road K north of town.
Two foot diameter tree down. Power lines down on residence.
Total rainfall just under 3 inches in the last 90 minutes.
Residents being evacuated in town due to creek flooding. Highway 4 also closed due to flooding.
Seven power poles were blown down near the intersection of northwest 26th Street and northwest 110th by high winds.
Highway 3 closed by flooding.
A farm wagon was blown into a pole. Branches broken up to 6 inches in diameter by winds.
Six inches of water standing in streets. Half inch diameter hail and wind gusts to 20 MPH.
Extensive flooding along 1st, 2nd, and 3rd streets in town. Foundation caved in with up to 4 feet of water in basements.
Many basements flooded in Humboldt. Also bridge under water north of town on Highway 169.
Twenty four hour rainfall total.
Twenty four hour rainfall total.
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, June 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: 227326, 227330, 227333, 227328, 227329, 227346, 227334, 227339, 227337, 227341, 227382, 227343, 227349, 227353, 227352, 227370, 227371, 227373, 227374, 227222, 227345, 227223, 227320, 227348, 227463, 227365, 227376, 236012, 227323, 234432, 227354, 227324, 227358, 227362, 227363.