Jul 19, 2011
Another night in the long duration heat wave brought another round of nocturnal convection. Early in the morning of the 19th, a weak surface boundary set up across northern South Dakota into west central Minnesota. As the low level jet and warm advection increased after midnight, thunderstorms began to fire. The air mass was extremely unstable with precipitable water values over two inches. The thunderstorms moved very slowly, and with the high amount of available moisture, heavy rain and flash
Source: NOAA National Weather Service Storm Events Database (event 333729). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Cass County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.