FloodZoneMap.org

A surface boundary stretching from southwest into north central North Dakota served as the primary focal point for thunderstorm development in an atmosphere of very high instability. Initially, large hail was the main threat, though a couple of tornadoes developed in an area of enhanced low level shear. Later, storms mainly developed along an old outflow boundary and were slow moving. This combined with a moisture rich atmosphere which led to a heavy rain threat, in addition to a hail and strong