Damaging Winds in Iowa, August 8, 2010

Name: Damaging Winds in Iowa, August 8, 2010
Start: 2010-08-08T18:00
End: 2010-08-08T19:40
Location: Iowa

August 8, 2010 · NWS FSD · 12 events in 4 counties and zones

Thunderstorms produced damaging winds in much of northwest Iowa, excluding the far northwestern corner of the state, during the early evening of August 8th.

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: 1
Property damage: $695,000
Crop damage: None recorded
Events: 12

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 FSD wrote it up.

Thunderstorms produced damaging winds in much of northwest Iowa, excluding the far northwestern corner of the state, during the early evening of August 8th.

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 Sioux Falls, SD wrote its last area forecast discussion before the first event at Aug 8, 2:58 PM CST, 3 hours 2 minutes earlier.

Area forecast discussion, Aug 8, 2:58 PM CST, 3 hours 2 minutes before

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
358 PM CDT SUN AUG 8 2010

.DISCUSSION...

A LOT GOING ON THIS AFTERNOON WITH CONDITIONS IN PLACE FOR SOME LATE
AFTERNOON AND EVENING SEVERE WEATHER COUPLED WITH A HEAVY RAIN
THREAT OVER THE ALREADY SATURATED GROUND OF SOUTHEAST SOUTH
DAKOTA...NORTHWEST IOWA AND NORTHEAST NEBRASKA OVERNIGHT. HAIL AND
WIND THE GREATEST THREAT WITH JUST A MINIMUM THREAT OF TORNADOES.
EVEN LARGE HAIL MAY BE DIFFICULT WITH FREEZING LEVEL AROUND 14K
FT.  FLASH FLOOD WATCH ISSUED EARLIER THIS AFTERNOON FOR THE
SATURATED AREA MOST LIKELY TO PICK UP AN INCH OR MORE RAIN TONIGHT
BEFORE THE CONVECTION MOVES EAST OF FORECAST AREA.

OVERNIGHT LOWS WILL AGAIN HOLD IN THE 70S AT MOST LOCATIONS AND THE
HUMIDITY LEVELS WILL REMAIN HIGH.  /GH

WITH REGARD TO HEAT HEADLINES...HAVE ELECTED TO KEEP THE CURRENT
HEAT ADVISORY HEADLINE AS IS...CONTINUING UNTIL 00Z ON TUESDAY...BUT
WILL CHANGE CURRENT HEAT WARNING TO A HEAT ADVISORY AS AREA WILL NOT
MEET WARNING CRITERIA ON MONDAY. SOME UNCERTAINTY EVEN WITH THE HEAT
ADVISORY...DEPENDENT ON AMOUNT OF RAIN COOLED AIR FROM ANY LEFT OVER
CONVECTION EARLY ON MONDAY. OVERNIGHT SHIFT CAN FURTHER ASSESS THIS.

OTHERWISE...MAY BE SOME LINGERING CONVECTION IN OUR FAR SOUTHEAST ON
MONDAY MORNING...THEN NEXT CHANCE OF CONVECTION WILL BE POSSIBLE IN THE
LATE AFTERNOON IN OUR SOUTH WITH INCREASING THETA E
ADVECTION/INSTABILITY AND A BOUNDARY JUST TO THE SOUTH OF OUR CWA.
AT THIS POINT...LOOKING FOR HIGHS UPPER 80S TO LOWER 90S WITH
UNCOMFORTABLE DEW POINTS IN THE MID/UPPER 70S. FRONT PUSHES BACK TO
THE NORTH ON MONDAY NIGHT...WITH CONVECTION INCREASING OVER THE
CWA AS ANOTHER SHORTWAVE TRACKS ACROSS THE AREA. DECENT RAINFALL
POSSIBLE AGAIN WITH PW AMOUNTS AROUND 1.5 TO 2 INCHES. WARM MINS IN
THE LOWER 70S.

FRONT PUSHES SLOWLY TO THE NORTH INTO TUESDAY...KEEPING A CHANCE OF
CONVECTION IN OUR NORTH...TO BE FOLLOWED BY ANOTHER BOUNDARY
SWINGING ACROSS THE AREA ON TUESDAY NIGHT AND WEDNESDAY PROVIDING
ANOTHER CHANCE OF PRECIPITATION. CONTINUING ABOVE NORMAL TEMPERATURE
WISE BOTH DAYS...WITH HIGHS UPPER 80S TO LOWER 90S AND LOWS IN THE
LOWER 70S.

FOR THE END OF THE WEEK INTO THE WEEKEND...SLOWLY TRANSITIONING
WEATHER PATTERN THROUGH THE PERIOD AS THE UPPER LEVEL RIDGE BEGINS
TO LOSE HOLD OVER OUR AREA. TYPICAL OVERALL MODEL AGREEMENT IN THE
SYNOPTIC FLOW...BUT DIFFERING IN TIMING OF SMALLER FEATURES EMBEDDED
IN THE UPPER LEVEL FLOW. THURSDAY AND FRIDAY LOOKING TO REMAIN VERY
WARM AND HUMID WITH HIGHS IN THE UPPER 80S TO LOWER 90S AND
DEWPOINTS IN THE UPPER 60S TO LOWER 70S. MODELS INDICATING A MORE
SIGNIFICANT TROUGH DIVING INTO THE NORTHERN PLAINS BY THE
WEEKEND...WITH TEMPERATURES FALLING BACK TO CLOSER TO NORMAL UNDER A
NORTHWESTERLY FLOW. THERE WILL BE INTERMITTENT RAIN CHANCES THROUGH
THE PERIOD...BUT KEPT ONLY SMALL CHANCE POPS WITH LOW CONFIDENCE ON
TIMING DUE TO MODEL DIFFERENCES.  /JM

&&

.AVIATION...

THUNDERSTORMS PRODUCING MVFR TO LOCAL IFR CONDITIONS LIKELY ACROSS
THE SOUTHEAST PORTION OF THE FORECAST AREA THROUGH AT LEAST
MIDNIGHT. LESS CHANCE OF MVFR CIGS VICINITY OF KHON BUT STILL
THUNDERSTORMS POSSIBLE THAT AREA THROUGH EARLY EVENING. SOME FOG AND
LOW STRATUS POSSIBLE AT KSUX AND KFSD TOWARD MONDAY MORNING AS RAIN
COOLED AIR FORMS A STRATUS DECK UNTIL BURNOFF AROUND 8AM.  /GH

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

IA...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR
     IAZ012>014-020>022-031-032.

     HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR IAZ001>003.

     FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH MONDAY
     MORNING FOR IAZ001>003-012>014-020>022-031-032.

     HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT MONDAY FOR
     IAZ012>014-020>022-031-032.

MN...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR MNZ098.

     FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH MONDAY
     MORNING FOR MNZ098.

NE...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR NEZ013-
     014.

     FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH MONDAY
     MORNING FOR NEZ013-014.

     HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT MONDAY FOR
     NEZ013-014.

SD...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR
     SDZ068>071.

     HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR SDZ038-050-052>054-
     057>067.

     FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH MONDAY
     MORNING FOR SDZ062-066>071.

     HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT MONDAY FOR
     SDZ068>071.

&&

Hazardous weather outlook, Aug 8, 10:14 AM CST, 7 hours 46 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1114 AM CDT SUN AUG 08 2010

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-091200-
AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA-
CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE-
DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON-
IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN-
LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN-
OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN-
SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON-
1114 AM CDT SUN AUG 08 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA...
SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
SCATTERED THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON WEST OF
INTERSTATE 29 AND NORTH OF INTERSTATE 90...AND THEN MERGE INTO A
LARGE AREA OF THUNDERSTORMS MAINLY FROM SOUTHEAST SOUTH DAKOTA TO
NORTHWEST IOWA THIS EVENING. LOCALLY DAMAGING WINDS AND LARGE
HAIL WILL BE POSSIBLE...BUT THE MAIN THREAT FROM THESE
THUNDERSTORMS WILL BE VERY HEAVY RAIN WITH 1 TO 3 INCHES RAINFALL
POSSIBLY CAUSING LOCAL FLASH FLOODING THIS EVENING AND OVERNIGHT.

FLOODING...
RIVER FLOODING WILL CONTINUE ALONG THE JAMES RIVER FOR AN
EXTENDED PERIOD. RIVER FLOODING IS ALSO OCCURRING OVER PARTS OF
THE VERMILLION RIVER. WITH NO ADDITIONAL RAINFALL THE VERMILLION
RIVER WILL CONTINUE TO SLOWLY FALL OVER THE NEXT FEW DAYS.

EXCESSIVE TEMPERATURES...
IT WILL BE HOT AND HUMID THIS AFTERNOON FROM SOUTHEAST SOUTH
DAKOTA TO NORTHWEST IOWA AND FAR NORTHEAST NEBRASKA. HIGHEST HEAT
INDICES THIS AFTERNOON SHOULD BE FROM 100 TO 110 IN THE LOWER
JAMES VALLEY OF SOUTH DAKOTA TO NORTHWEST IOWA...AND 95 TO 100
ELSEWHERE IN THE AREA.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

VERY WARM AND HUMID AIR WILL CONTINUE TO CAUSE UNCOMFORTABLE
CONDITIONS MONDAY AFTERNOON THROUGH TUESDAY...ESPECIALLY SOUTH OF
INTERSTATE 90. AFTERNOON HEAT INDICES WILL GENERALLY RANGE FROM
AROUND 105 SOUTH TO 95 NORTH ACROSS THE FORECAST AREA.

IN ADDITION...SCATTERED THUNDERSTORMS WITH LOCALLY HEAVY RAINS
WILL AGAIN BE POSSIBLE MONDAY NIGHT AND EARLY TUESDAY IN THE
AREA...ESPECIALLY ALONG AND NORTH OF INTERSTATE 90.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE POSSIBLE AFTER 4PM

&&

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.WEATHER.GOV/SIOUXFALLS. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.

In the hours before

Local storm report, Aug 8, 4:28 PM CST, 1 hour 32 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
528 PM CDT SUN AUG 08 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0526 PM     FLASH FLOOD      ENE AVON                43.01N 98.06W
08/08/2010                   BON HOMME          SD   TRAINED SPOTTER

            BACK YARD IS UNDER WATER

&&

LAFLIN

Local storm report, Aug 8, 4:41 PM CST, 1 hour 19 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
541 PM CDT SUN AUG 08 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0535 PM     TSTM WND GST     YANKTON                 42.89N 97.39W
08/08/2010  M58 MPH          YANKTON            SD   ASOS

&&

JM

Local storm report, Aug 8, 4:45 PM CST, 1 hour 15 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
545 PM CDT SUN AUG 08 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0515 PM     TSTM WND GST     5 WSW YANKTON           42.87N 97.49W
08/08/2010  E70 MPH          YANKTON            SD   TRAINED SPOTTER

            CAMPERS OVERTURNED AT LEWIS AND CLARK CAMPGROUND

&&

LAFLIN

Local storm report, Aug 8, 4:51 PM CST, 1 hour 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
551 PM CDT SUN AUG 08 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0550 PM     TSTM WND GST     2 W IRENE               43.08N 97.20W
08/08/2010  M60 MPH          YANKTON            SD   TRAINED SPOTTER

&&

LIEBL

Local storm report, Aug 8, 4:53 PM CST, 1 hour 7 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
553 PM CDT SUN AUG 08 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0552 PM     FLASH FLOOD      2 ESE YANKTON           42.88N 97.36W
08/08/2010                   YANKTON            SD   TRAINED SPOTTER

            STREET FLOODING IN YANKTON AND DITCHES ARE FULL

&&

LAFLIN

Local storm report, Aug 8, 5:38 PM CST, 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
638 PM CDT SUN AUG 08 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0625 PM     TSTM WND GST     6 N DIXON               42.50N 96.99W
08/08/2010  E60 MPH          DIXON              NE   TRAINED SPOTTER

            BRANCHES DOWN

&&

LAFLIN

The radar

The Sioux Falls radar (KFSD), 122 km away, was scanning. The volume nearest the first event began at 00:01 UTC.

Open the radar archive at this moment

Event by event

12 thunderstorm wind. Local standard time, as filed.

Thunderstorm Wind, Woodbury

When: August 8, 6:00 PM CST
Where: Woodbury County, 1.02 mi W of Springdale to 1.47 mi SSW of Sioux City
Measured: 61 kt (70 mph) estimated gust
Property damage: $50,000
Reported by: Law Enforcement
Coordinates: 42.520, -96.390

Thunderstorm winds caused widespread tree damage, including several large trees and numerous branches blown down. Some of the tree debris blocked roads and caused minor damage to homes. The winds also blew down power lines, causing a power outage, and blew part of a freight train off its tracks.

Thunderstorm Wind, Woodbury

When: August 8, 6:09 PM CST
Where: Woodbury County, 3.49 mi S of Salix
Measured: 52 kt (60 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 42.270, -96.290

Thunderstorm winds caused tree damage, including several branches blown down.

Thunderstorm Wind, Woodbury

When: August 8, 6:15 PM CST
Where: Woodbury County, 0.69 mi S of Moville
Measured: 52 kt (60 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 42.490, -96.070

Thunderstorm winds caused tree damage, including large branches blown down.

Thunderstorm Wind, Woodbury

When: August 8, 6:22 PM CST
Where: Woodbury County, 0.51 mi W of Sioux City
Measured: 57 kt (66 mph) measured gust
Reported by: Law Enforcement
Coordinates: 42.500, -96.390

Thunderstorm Wind, Ida

When: August 8, 6:40 PM CST
Where: Ida County, 3 mi N of Holstein to 0.86 mi NE of Holstein
Measured: 65 kt (75 mph) estimated gust
Property damage: $100,000
Reported by: COOP Observer
Coordinates: 42.523, -95.550

Thunderstorm winds destroyed a machine shed, heavily damaged a large shed at a manufacturing plant, overturned a livestock trailer and a large grain wagon, destroyed a small garage, destroyed or damaged several small sheds, and caused tree damage, including several large trees blown down. A house was damaged by debris from the destroyed machine shed, while other buildings and vehicles sustained damage from falling trees and tree debris. The winds also caused an unknown amount of damage to corn crops.

Thunderstorm Wind, Ida

When: August 8, 6:47 PM CST
Where: Ida County, 2.76 mi N of Galva
Measured: 61 kt (70 mph) estimated gust
Property damage: $10,000
Reported by: Emergency Manager
Coordinates: 42.540, -95.420

Thunderstorm winds blew the roof off a barn, blew down power lines, and caused tree damage.

Thunderstorm Wind, Ida

When: August 8, 6:50 PM CST
Where: Ida County, 0.69 mi S of Ida Grove
Measured: 56 kt (64 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 42.340, -95.470

Thunderstorm winds caused tree damage, including numerous branches blown down.

Thunderstorm Wind, Buena Vista

When: August 8, 7:20 PM CST
Where: Buena Vista County, 1.53 mi E of Hanover
Measured: 61 kt (70 mph) estimated gust
Property damage: $10,000
Reported by: Trained Spotter
Coordinates: 42.600, -95.350

Thunderstorm winds caused widespread tree damage, including numerous large branches blown down. The winds also bent a flag pole.

Thunderstorm Wind, Buena Vista

When: August 8, 7:20 PM CST
Where: Buena Vista County, 2.64 mi ESE of Storm Lake Arpt
Measured: 61 kt (70 mph) estimated gust
Injuries: 1 direct, 0 indirect
Property damage: $25,000
Reported by: Broadcast Media
Coordinates: 42.590, -95.200

Thunderstorm winds blew over a large semi truck, blocking the road and causing minor injuries to the driver.

Thunderstorm Wind, Buena Vista

When: August 8, 7:25 PM CST
Where: Buena Vista County, 1.38 mi N of Storm Lake to 1.02 mi W of Lakeside
Measured: 65 kt (75 mph) estimated gust
Property damage: $500,000
Reported by: Newspaper
Coordinates: 42.670, -95.200

Thunderstorm winds blew the roof off a manufacturing plant, damaged docks and boats along the lake, caused widespread tree damage including numerous large trees blown down, blew down power lines and poles, resulting in power outages, damaged or destroyed several small sheds, blew down several awnings on businesses, snapped a 4 inch by 4 inch street sign pole, and blew shingles off roofs. Numerous vehicles, homes, and businesses sustained minor damage directly from the wind, while other vehicles and homes were damaged by falling trees and tree debris, some heavily.

Thunderstorm Wind, Clay

When: August 8, 7:40 PM CST
Where: Clay County, Spencer
Measured: 52 kt (60 mph) measured gust
Reported by: Broadcast Media
Coordinates: 43.150, -95.150

Thunderstorm Wind, Clay

When: August 8, 7:40 PM CST
Where: Clay County, 0.51 mi W of Webb
Measured: 52 kt (60 mph) estimated gust
Reported by: COOP Observer
Coordinates: 42.950, -95.010

Thunderstorm winds caused tree damage, including several large branches blown down.

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.

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

The same day elsewhere

Every storm in Iowa in 2010 Every state in 2010 This day in weather history Warnings 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: 257079, 257088, 257092, 257097, 257099, 257101, 257102, 257103, 257107, 257113, 257117, 257118.