May 17, 2013
An unstable airmass was in place over northern Iowa with an outflow boundary draped across the north central counties into southwest Minnesota. This boundary served as a focusing mechanism for thunderstorm development. The freezing level was relatively low at around 11,500 feet. CAPE available in the -10 to -30 layer of the atmosphere was between 200 and 400 J/kg. The atmosphere became unstable with afternoon highs in the upper 70s to low 80s and dewpoint temperatures in the mid 60s. CAPE w
Source: NOAA National Weather Service Storm Events Database (event 440183). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Palo Alto County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.