Storm Events Database

Storm Events Database

Event Details:

Event Tornado
-- Scale EF0
-- Length 2.67 Miles
-- Width 60 Yards
State IOWA
County/Area HAMILTON
WFO DMX
Report Source Storm Chaser
NCEI Data Source CSV
Begin Date 2018-07-19 13:56 CST-6
Begin Location 17E DUNCOMBE
Begin Lat/Lon 42.4887/-93.656
End Date 2018-07-19 14:05 CST-6
End Location 19E DUNCOMBE
End Lat/Lon 42.5143/-93.6166
Deaths Direct/Indirect 0/0 (fatality details below, when available...)
Injuries Direct/Indirect 0/0
Property Damage 0.00K
Crop Damage 1.00K
Episode Narrative A setup for some rotating storms was in place over much of central and southern Iowa. A low pressure system situated northwest of the state slid to the northeast throughout the day, eventually moving into western and central Minnesota. Given its fairly mature frontal situation, an occluded front dropped into northwest Iowa with the warm front extending E/SE from central Iowa and the cold front dropping back to the SW. At the surface within the warm sector observations were favorable with temperatures into the mid 80s and dew points in the low to mid 70s. Looking in more detail, lifted condensation levels were quite low with values under 750 meters, MUCAPE values were modest in the 1000-3000 J/kg range, effective bulk shear was in excess of 40 kts, and effective storm relative helicity was around 200 m2/s2 to name a few. Resulting composite indices correctly highlighted an increased chance for supercells and tornadic potential as seen with supercell composite values in excess of 12 and significant tornado parameter values in the 3 to 5 range in the afternoon. All of which taking into account the general setup, understandably unable to account for storms potentially tapping into additional shear and helicity generated from rooting themselves along outflow boundaries.
The result was a sizable tornado outbreak across Iowa, including more than a dozen confirmed tornadoes. The tornadoes of most note occurred in the NE Des Moines Metro (specifically Bondurant), Pella, and Marshalltown. The Bondurant area actually experienced two tornadoes, which were concurrently on the ground, but fortunately only one actually caused damage (EF2) within town. The Pella tornado tacked on the north side of town, directly hitting the Vermeer plant, causing EF3 damage. The Marshalltown tornado entered the town from the NW and tracked into the downtown area before exiting and weakening east of town. Widespread damage was experienced in Marshalltown including to the Lennox plant and the County Courthouse. All in all, while numerous injuries were experienced and millions of dollars of damage, no direct fatalities were reported from the tornadoes.
Event Narrative This tornado developed northwest of Blairsburg and moved northeast through agricultural land. The tornado dissipated just prior to crossing County Highway D20. Only damage was to crops.


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Event Map:

Note: The tornado track is approximate based on the beginning (B) and ending (E) locations. The actual tornado path may differ from a straight line.
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Measure
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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 35 320.375M 24.00K
CURLEW PALO ALTO CO. IA 07/19/2018 10:45 CST-6 Funnel Cloud 0 0 0.00K 0.00K
ROLFE POCAHONTAS CO. IA 07/19/2018 11:08 CST-6 Funnel Cloud 0 0 0.00K 0.00K
EAGLE GROVE WRIGHT CO. IA 07/19/2018 13:30 CST-6 Tornado EF0 0 0 0.00K 0.50K
WOOLSTOCK WRIGHT CO. IA 07/19/2018 13:35 CST-6 Tornado EF0 0 0 0.00K 0.70K
WOOLSTOCK WRIGHT CO. IA 07/19/2018 13:42 CST-6 Tornado EF0 0 0 0.00K 0.10K
ENTERPRISE POLK CO. IA 07/19/2018 13:48 CST-6 Tornado EF0 0 0 2.00K 0.00K
ENTERPRISE POLK CO. IA 07/19/2018 13:50 CST-6 Tornado EF2 0 0 35.00K 3.50K
BONDURANT POLK CO. IA 07/19/2018 13:51 CST-6 Tornado EF2 0 0 250.00K 1.00K
STORY CITY STORY CO. IA 07/19/2018 13:52 CST-6 Tornado EF0 0 0 0.00K 0.50K
DUNCOMBE HAMILTON CO. IA 07/19/2018 13:56 CST-6 Tornado EF0 0 0 0.00K 1.00K
STORY CITY STORY CO. IA 07/19/2018 14:08 CST-6 Funnel Cloud 0 0 0.00K 0.00K
MAXWELL STORY CO. IA 07/19/2018 14:13 CST-6 Funnel Cloud 0 0 0.00K 0.00K
SANTIAGO POLK CO. IA 07/19/2018 14:15 CST-6 Funnel Cloud 0 0 0.00K 0.00K
COLFAX JASPER CO. IA 07/19/2018 14:18 CST-6 Tornado EF0 0 0 0.00K 1.00K
STORY CITY STORY CO. IA 07/19/2018 14:21 CST-6 Funnel Cloud 0 0 0.00K 0.00K
ROLAND STORY CO. IA 07/19/2018 14:22 CST-6 Tornado EF0 0 0 0.00K 0.00K
HARTFORD WARREN CO. IA 07/19/2018 14:23 CST-6 Funnel Cloud 0 0 0.00K 0.00K
PRAIRIE CITY JASPER CO. IA 07/19/2018 14:28 CST-6 Tornado EF0 0 0 0.00K 0.80K
COLFAX JASPER CO. IA 07/19/2018 14:31 CST-6 Funnel Cloud 0 0 0.00K 0.00K
COLLINS STORY CO. IA 07/19/2018 14:35 CST-6 Tornado EF0 0 0 0.00K 0.80K
MONROE JASPER CO. IA 07/19/2018 14:35 CST-6 Funnel Cloud 0 0 0.00K 0.00K
CLYDE JASPER CO. IA 07/19/2018 14:39 CST-6 Funnel Cloud 0 0 0.00K 0.00K
MONROE JASPER CO. IA 07/19/2018 14:45 CST-6 Tornado EF0 0 0 8.00K 1.50K
OTLEY MARION CO. IA 07/19/2018 14:48 CST-6 Tornado EF1 0 0 0.00K 1.50K
OTLEY MARION CO. IA 07/19/2018 14:56 CST-6 Tornado EF0 0 0 0.00K 0.00K
PELLA MARION CO. IA 07/19/2018 15:01 CST-6 Tornado EF3 0 13 120.000M 4.50K
OTLEY MARION CO. IA 07/19/2018 15:03 CST-6 Funnel Cloud 0 0 0.00K 0.00K
PELLA MARION CO. IA 07/19/2018 15:09 CST-6 Funnel Cloud 0 0 0.00K 0.00K
BROMLEY MARSHALL CO. IA 07/19/2018 15:11 CST-6 Tornado EF0 0 0 0.00K 0.10K
PEORIA MAHASKA CO. IA 07/19/2018 15:13 CST-6 Tornado EF2 0 0 80.00K 1.50K
PELLA MARION CO. IA 07/19/2018 15:14 CST-6 Hail 1.50 in. 0 0 0.00K 0.00K
ALBION MARSHALL CO. IA 07/19/2018 15:15 CST-6 Funnel Cloud 0 0 0.00K 0.00K
PEORIA MAHASKA CO. IA 07/19/2018 15:15 CST-6 Tornado EF0 0 0 0.00K 0.50K
BROMLEY MARSHALL CO. IA 07/19/2018 15:17 CST-6 Funnel Cloud 0 0 0.00K 0.00K
CLEMONS MARSHALL CO. IA 07/19/2018 15:17 CST-6 Funnel Cloud 0 0 0.00K 0.00K
MARIETTA MARSHALL CO. IA 07/19/2018 15:24 CST-6 Tornado EF3 0 22 200.000M 4.00K
OSKALOOSA ROTH ARPT MAHASKA CO. IA 07/19/2018 15:50 CST-6 Tornado EF0 0 0 0.00K 0.50K
(OTM)OTTUMWA INDSTRL WAPELLO CO. IA 07/19/2018 16:12 CST-6 Thunderstorm Wind 62 kts. MG 0 0 0.00K 0.00K
RUTLEDGE WAPELLO CO. IA 07/19/2018 16:42 CST-6 Hail 1.00 in. 0 0 0.00K 0.00K
Totals: 0 35 320.375M 24.00K