At least $9.68 million in damages were reported. Background A series of potent storm systems traversed the US during March 1913, described by the US Weather Bureau as "...the most extraordinary situation in regards to the weather since the creation of the bureau." Anomalously high moisture had gathered near the US Gulf Coast, as an intense upper level storm system moved in from the west. According to retrospective numerical modeling of this event, a strong cap aloft was in place over the central Plains, as is common as the elevated mixed layer advects eastward from the Rockies. Observations taken at 13Z 23 March 1913 showed that surface low pressure was located in Colorado, and a warm front stretched due eastward from there into Illinois. Morning temperatures near this front were in the 30s. South of the front warmer and moister air was present, but dewpoints in the upper 50s were confined to southern Oklahoma and Arkansas, far away from where the tornadoes were to later occur in eastern Nebraska and western Iowa. As the day progressed, the surface low ejected through Nebraska, with a dry line and trailing cold front. South winds blowing 40-50 knots at times brought the moister air rapidly northward. One of the worst dust storms on record occurred behind the dry line in western Kansas, but in the warm sector the day remained dry until mid afternoon when light showers began to form in central Nebraska. A cooperative observer in Osceola noted that the wind shifted from S to NW at 2230Z (4:30 PM local). Professors at the University of Nebraska at Lincoln noted that the relative humidity there jumped from 53% at 2150Z to 78% at 2230Z, indicating much higher dewpoints had rapidly arrived in Lincoln since the cold front was still to the west near Osceola. They also noted that the surface low passed just to the north of Omaha and was in western Iowa at 01Z 24 March 1913. With all of this observed information, it is likely that the quality moisture required to produce convection strong enough for tornadoes arrived just an hour or two before the strong forcing associated with the surface low pressure and attendant frontal systems. At the time of the tornadoes it is estimated that surface temperatures were in the upper 60s, dewpoints were in the upper 50s, and surface winds were southerly around 25-30 knots. Numerical modeling