Jun 29, 2014
A powerful upper level system was moving into south central Canada. The upper level winds were increasing as a closed upper low settled into that area. Warm air advection continued across Iowa through the night of the 29th into the morning of the 30th. The atmosphere was very unstable with CAPE values around 4000 J/kg. Downdraft CAPE was between 1000 and 1500 J/kg, with CAPE in the -10 to -30 C layer of the atmosphere in the 600 to 800 J/kg range. Strong shear was present, with an effective
Source: NOAA National Weather Service Storm Events Database (event 516164). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Grundy County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.