Storm Events Database

Event Details

Event Thunderstorm Wind
Magnitude 61 kts.
State IOWA
County/Area PALO ALTO
WFO DMX
Report Source Trained Spotter
NCDC Data Source CSV
Begin Date 2010-07-17 22:40:00.0 CST-6
Begin Location 1SE EMMETSBURG
Begin Lat/Lon 43.11/-94.68
End Date 2010-07-17 22:40:00.0 CST-6
Deaths Direct/Indirect 0/0 (fatality details below, when available...)
Injuries Direct/Indirect 0/0
Property Damage 10.00K
Crop Damage 10.00K
Episode Narrative A very unstable airmass was in place over Iowa as a cold front approached from the west. High temperatures the previous day were in the upper 80s and 90s for the most part, with 101 at Fairfield. Dewpoint readings were in the 70s east to near 80 over the west. CAPE was in the 4000 to 5000 J/kg range with lifted indices of -8 to -11 C. Downdraft CAPE was quite high, 1200-1400 J/kg. CAPE in the -10 to -30 C layer of the atmosphere was between 300 and 500 J/kg. The atmosphere was quite strongly sheared with 45 to 60 kts of shear. Precipitable water was low, only 1 to 1.5 inches. With the relatively dry air, the LCL was between 1500 and 2500 meters. The airmass was also quite warm with the freezing level around 15,600 feet. Thunderstorms formed in two clusters. One extended from Minnesota southwest into eastern South Dakota. The other area was over central Nebraska. The convective area from South Dakota dropped southeast into Iowa during the late evening hours. It produced high winds and hail as it did. Hail was not the major mode of severe weather. Most of the larger hail occurred during the early stages of the storm. Golf ball size hail fell west of Graettinger in Palo Alto County for the largest hail report. The cluster of storms organized into a small derecho as it approached Fort Dodge. The derecho raced southeast through the Des Moines area and into southeast Iowa. It produced some hail as it did, but by in large high winds were the primary threat. Winds of 60 to 75 MPH were common, causing considerable tree damage. High winds of 65 to 75 MPH roared through Ames. A shelter at the Iowa State Veterinary Medicine School was blown over. Several horses were injured by the collapse. University officials has to euthanize one horse due to severe injuries. A measured wind gust of 84 MPH was recorded on the northwest side of the Des Moines Metro area. Power was knocked out to nearly 40,000 customers in central Iowa by the storms. Damage reports from along the path of the derecho were widespread. Grain bins were destroyed as well as numerous out buildings. Tree and power line damage was extensive all the way from the Minnesota border through south central Iowa. Heavy rain was also an issue with the storms. Rainfall of 1 to 2 inches per hour fell with the storms from Fort Dodge into the Des Moines area. Flash flooding was reported in Marion County. Heavy rainfall of 2 to 4 inches in under 2 hours flooded city streets in Knoxville, some 4 feet deep, with cars stalled in city streets. Water was also over the road southeast of Melcher-Dallas in Marion County. Flash flooding was reported in Webster City. Flooding blew manhole covers off and stalled several cars in the city. As the storm moved through the Raymond area of Black Hawk County, lightning struck a house. It blew a basketball size hole in the roof and caused electrical damage to the house and some structural damage to ceilings.
Event Narrative Numerous trees down, some uprooted.


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All events for this episode:

Location County/Zone St. Date Time T.Z. Type Mag Dth Inj PrD CrD
Totals: 0 0 3.108M 840.00K
ESTHERVILLE EMMET CO. IA 07/17/2010 22:10 CST-6 Hail 1.00 in. 0 0 1.00K 10.00K
GRAETTINGER PALO ALTO CO. IA 07/17/2010 22:25 CST-6 Hail 1.75 in. 0 0 5.00K 15.00K
GRAETTINGER PALO ALTO CO. IA 07/17/2010 22:25 CST-6 Hail 1.25 in. 0 0 5.00K 200.00K
EMMETSBURG PALO ALTO CO. IA 07/17/2010 22:40 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 10.00K
WHITTEMORE KOSSUTH CO. IA 07/17/2010 23:10 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
HAVELOCK POCAHONTAS CO. IA 07/17/2010 23:20 CST-6 Thunderstorm Wind 61 kts. EG 0 0 25.00K 50.00K
PLOVER POCAHONTAS CO. IA 07/17/2010 23:38 CST-6 Hail 1.00 in. 0 0 1.00K 10.00K
DAKOTA CITY HUMBOLDT CO. IA 07/17/2010 23:40 CST-6 Thunderstorm Wind 65 kts. EG 0 0 200.00K 100.00K
DAKOTA CITY HUMBOLDT CO. IA 07/18/2010 00:00 CST-6 Thunderstorm Wind 65 kts. EG 0 0 100.00K 0.00K
FT DODGE WEBSTER CO. IA 07/18/2010 00:00 CST-6 Heavy Rain 0 0 0.00K 0.00K
DAKOTA CITY HUMBOLDT CO. IA 07/18/2010 00:05 CST-6 Thunderstorm Wind 61 kts. EG 0 0 25.00K 0.00K
BADGER WEBSTER CO. IA 07/18/2010 00:21 CST-6 Thunderstorm Wind 56 kts. EG 0 0 50.00K 10.00K
EAGLE GROVE WRIGHT CO. IA 07/18/2010 00:28 CST-6 Thunderstorm Wind 50 kts. MG 0 0 10.00K 0.00K
PALM GROVE WEBSTER CO. IA 07/18/2010 00:45 CST-6 Thunderstorm Wind 65 kts. EG 0 0 50.00K 10.00K
WEBSTER CITY HAMILTON CO. IA 07/18/2010 00:45 CST-6 Thunderstorm Wind 65 kts. EG 0 0 250.00K 100.00K
GOWRIE WEBSTER CO. IA 07/18/2010 01:00 CST-6 Thunderstorm Wind 53 kts. EG 0 0 5.00K 0.00K
POLK CITY POLK CO. IA 07/18/2010 01:00 CST-6 Heavy Rain 0 0 0.00K 0.00K
SLATER STORY CO. IA 07/18/2010 01:00 CST-6 Heavy Rain 0 0 0.00K 0.00K
WEBSTER CITY ARPT HAMILTON CO. IA 07/18/2010 01:00 CST-6 Thunderstorm Wind 52 kts. EG 0 0 2.00K 0.00K
BOXHOLM BOONE CO. IA 07/18/2010 01:05 CST-6 Thunderstorm Wind 52 kts. EG 0 0 10.00K 0.00K
BOONE BOONE CO. IA 07/18/2010 01:12 CST-6 Thunderstorm Wind 65 kts. EG 0 0 200.00K 50.00K
WEBSTER CITY HAMILTON CO. IA 07/18/2010 01:15 CST-6 Flash Flood 0 0 100.00K 0.00K
BOONE BOONE CO. IA 07/18/2010 01:23 CST-6 Thunderstorm Wind 61 kts. EG 0 0 75.00K 0.00K
BOONE BOONE CO. IA 07/18/2010 01:23 CST-6 Thunderstorm Wind 56 kts. MG 0 0 25.00K 0.00K
BOONE MUNI ARPT BOONE CO. IA 07/18/2010 01:25 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
MADRID BOONE CO. IA 07/18/2010 01:27 CST-6 Thunderstorm Wind 61 kts. EG 0 0 100.00K 50.00K
ERICSON BOONE CO. IA 07/18/2010 01:28 CST-6 Thunderstorm Wind 63 kts. MG 0 0 50.00K 0.00K
AMES STORY CO. IA 07/18/2010 01:30 CST-6 Thunderstorm Wind 61 kts. EG 0 0 25.00K 0.00K
AMES STORY CO. IA 07/18/2010 01:30 CST-6 Thunderstorm Wind 65 kts. EG 0 0 500.00K 100.00K
AMES STORY CO. IA 07/18/2010 01:38 CST-6 Thunderstorm Wind 62 kts. MG 0 0 50.00K 0.00K
AMES STORY CO. IA 07/18/2010 01:40 CST-6 Thunderstorm Wind 52 kts. MG 0 0 25.00K 0.00K
MADRID BOONE CO. IA 07/18/2010 01:40 CST-6 Thunderstorm Wind 51 kts. MG 0 0 5.00K 0.00K
NEVADA MUNI ARPT STORY CO. IA 07/18/2010 01:40 CST-6 Thunderstorm Wind 61 kts. EG 0 0 50.00K 100.00K
AMES STORY CO. IA 07/18/2010 01:43 CST-6 Thunderstorm Wind 58 kts. MG 0 0 25.00K 0.00K
ANKENY POLK CO. IA 07/18/2010 01:46 CST-6 Thunderstorm Wind 56 kts. EG 0 0 100.00K 0.00K
DODGE FLD ARPT POLK CO. IA 07/18/2010 01:50 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 0.00K
WINDSOR HGTS POLK CO. IA 07/18/2010 01:55 CST-6 Thunderstorm Wind 65 kts. EG 0 0 75.00K 0.00K
HERROLD POLK CO. IA 07/18/2010 01:57 CST-6 Thunderstorm Wind 57 kts. MG 0 0 3.00K 0.00K
GILBERT STORY CO. IA 07/18/2010 02:00 CST-6 Thunderstorm Wind 57 kts. EG 0 0 10.00K 0.00K
LOVINGTON POLK CO. IA 07/18/2010 02:00 CST-6 Thunderstorm Wind 73 kts. MG 0 0 200.00K 0.00K
LOVINGTON POLK CO. IA 07/18/2010 02:00 CST-6 Thunderstorm Wind 65 kts. EG 0 0 150.00K 0.00K
GRIMES POLK CO. IA 07/18/2010 02:01 CST-6 Thunderstorm Wind 69 kts. EG 0 0 50.00K 0.00K
SHULER MINE DALLAS CO. IA 07/18/2010 02:04 CST-6 Thunderstorm Wind 56 kts. EG 0 0 15.00K 0.00K
ANKENY POLK CO. IA 07/18/2010 02:05 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 0.00K
ANKENY POLK CO. IA 07/18/2010 02:05 CST-6 Thunderstorm Wind 65 kts. EG 0 0 50.00K 0.00K
ADEL DALLAS CO. IA 07/18/2010 02:08 CST-6 Thunderstorm Wind 65 kts. EG 0 0 50.00K 0.00K
HADDEN HILL DALLAS CO. IA 07/18/2010 02:08 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 0.00K
URBANDALE POLK CO. IA 07/18/2010 02:09 CST-6 Thunderstorm Wind 61 kts. EG 0 0 25.00K 0.00K
NEVADA STORY CO. IA 07/18/2010 02:10 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 0.00K
(DSM)DES MOINES INTL POLK CO. IA 07/18/2010 02:14 CST-6 Thunderstorm Wind 52 kts. MG 0 0 2.00K 0.00K
CLARKSON WARREN CO. IA 07/18/2010 02:15 CST-6 Thunderstorm Wind 61 kts. EG 0 0 25.00K 15.00K
(DSM)DES MOINES INTL POLK CO. IA 07/18/2010 02:20 CST-6 Thunderstorm Wind 53 kts. MG 0 0 2.00K 0.00K
WINTERSET MADISON CO. IA 07/18/2010 02:21 CST-6 Thunderstorm Wind 69 kts. EG 0 0 25.00K 10.00K
BONDURANT POLK CO. IA 07/18/2010 02:25 CST-6 Thunderstorm Wind 52 kts. EG 0 0 2.00K 0.00K
HADDEN HILL DALLAS CO. IA 07/18/2010 02:26 CST-6 Thunderstorm Wind 57 kts. EG 0 0 100.00K 0.00K
INDIANOLA WARREN CO. IA 07/18/2010 02:26 CST-6 Thunderstorm Wind 61 kts. EG 0 0 15.00K 0.00K
WINTERSET MADISON CO. IA 07/18/2010 02:28 CST-6 Thunderstorm Wind 61 kts. MG 0 0 5.00K 0.00K
WINTERSET MADISON CO. IA 07/18/2010 02:30 CST-6 Thunderstorm Wind 61 kts. EG 0 0 15.00K 0.00K
PLEASANTVILLE MARION CO. IA 07/18/2010 02:40 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 0.00K
RAYMOND BLACK HAWK CO. IA 07/18/2010 02:50 CST-6 Lightning 0 0 10.00K 0.00K
CHARITON LUCAS CO. IA 07/18/2010 03:07 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 0.00K
KNOXVILLE MARION CO. IA 07/18/2010 03:43 CST-6 Heavy Rain 0 0 0.00K 0.00K
MORAVIA APPANOOSE CO. IA 07/18/2010 03:48 CST-6 Thunderstorm Wind 65 kts. EG 0 0 50.00K 0.00K
RATHBUN APPANOOSE CO. IA 07/18/2010 03:54 CST-6 Thunderstorm Wind 52 kts. EG 0 0 5.00K 0.00K
MYSTIC APPANOOSE CO. IA 07/18/2010 03:55 CST-6 Thunderstorm Wind 61 kts. EG 0 0 10.00K 0.00K
CLARKDALE APPANOOSE CO. IA 07/18/2010 04:00 CST-6 Thunderstorm Wind 63 kts. MG 0 0 25.00K 0.00K
COLUMBIA MARION CO. IA 07/18/2010 04:50 CST-6 Flash Flood 0 0 15.00K 0.00K
KNOXVILLE MARION CO. IA 07/18/2010 04:50 CST-6 Flash Flood 0 0 25.00K 0.00K
Totals: 0 0 3.108M 840.00K