Aug 9, 2010
A very unstable airmass was in place over Iowa. Afternoon temperatures warmed into the upper 80s to mid 90s, with dewpoint readings in the upper 70s to low 80s. A weak boundary extended out of eastern Nebraska across northern Iowa. This boundary helped to focus moisture. At the same time, a negatively tilted shortwave lifted northeast out of the Rockies into Nebraska during the afternoon and early evening. The lifted index fell to -10 to -14 C by evening with CAPE rising to 5000-7000 J/kg in
Source: NOAA National Weather Service Storm Events Database (event 259894). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Polk County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.