Storm Events Database

Event Details

Event Flash Flood
-- Flood Cause Heavy Rain
State IOWA
County/Area SAC
Report Source Law Enforcement
NCDC Data Source CSV
Begin Date 2010-07-23 07:45:00.0 CST-6
Begin Lat/Lon 42.3776/-94.9583
End Date 2010-07-23 10:00:00.0 CST-6
End Location 7ENE NEMAHA
End Lat/Lon 42.5474/-94.9387
Deaths Direct/Indirect 0/0 (fatality details below, when available...)
Injuries Direct/Indirect 0/0
Property Damage 250.00K
Crop Damage 10.00K
Episode Narrative A very unstable atmosphere was in place over Iowa with CAPE values around 2000 J/kg and lifted indices in the -8 to -10 C range. Precipitable water increased to around 2.25 inches along a boundary that extended from northeast into west central Iowa. Downdraft CAPE was in the 700 to 1000 J/kg range with 400 to 800 J/kg available in the -10 to -30 C layer of the atmosphere. The LCL was between 750 and 1000 meters. The freezing level was very high, around 16,000 feet. In spite of the relatively strongly sheared atmosphere, which was 35 to 45 kts, the thunderstorms had a hard time developing. A firm cap was in place with 700 mb temperatures of 14 to 15 C by early evening, and 500 mb temperatures of -4 C. Thunderstorms formed over northeast Iowa along the boundary. The thunderstorms back developed along the boundary well after sunset and became very efficient rain producers. The storms trained along the same line with a quick 2 to 3 inches of rain falling from west of Waterloo to near the Waterloo area. The rain fell in a short period of time, one to two hours, on top of ground that had received significant rainfall during the morning hours of the 22nd. This resulted in rapid runoff of water and flash flooding. The thunderstorms continued through the night with total rainfall north of Waterloo in the Denver area reaching 7.11 inches by sunrise. The line of storms back developed west across the state overnight. Heavy rainfall of 2 to 4 inches fell in a band extending west into the areas that saw flash flooding the previous day. Flash flooding was reported in Bremer, Webster, Wright, and Sac Counties. General flooding took place in many areas of Hamilton County as well. Severe weather was absent with the storms through the night. The tropical nature of the atmosphere limited the severe threat.
Event Narrative Sierra road was closed from Shasta Ave to 270th St due to flooding. Other road closures are on 170th St north of Sac City and 350th St near Grant City.


All events for this episode:

Location County/Zone St. Date Time T.Z. Type Mag Dth Inj PrD CrD
Totals: 0 0 1.340M 120.00K
DENVER BREMER CO. IA 07/23/2010 02:25 CST-6 Flash Flood 0 0 1.000M 100.00K
(FOD)FT DODGE MUNI A WEBSTER CO. IA 07/23/2010 04:30 CST-6 Flash Flood 0 0 25.00K 0.00K
DENVER BREMER CO. IA 07/23/2010 04:55 CST-6 Heavy Rain 0 0 0.00K 0.00K
CLARION WRIGHT CO. IA 07/23/2010 07:24 CST-6 Flash Flood 0 0 15.00K 0.00K
SAC CITY MUNI ARPT SAC CO. IA 07/23/2010 07:45 CST-6 Flash Flood 0 0 250.00K 10.00K
WEBSTER CITY HAMILTON CO. IA 07/23/2010 09:31 CST-6 Flash Flood 0 0 50.00K 10.00K
Totals: 0 0 1.340M 120.00K