May 21, 2004
A very unstable airmass was over Iowa and helped kick off the seasons first severe weather outbreak. At the surface a warm frontal boundary extended nearly east to west across the state and provided the focus for thunderstorm development. By the late afternoon, lifted indices were approaching -10 C. with CAPE values around 5000 J/kg over western Iowa. Surface temperatures warmed into the upper 80s with dew points in the low to mid 70s. A southwest surface wind of 15 to 25 kts pushed over the
Source: NOAA National Weather Service Storm Events Database (event 5394916). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Hancock County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.