Tornado and Hail in Iowa, October 6, 1994

The seasons first strongly dynamic weather system moved through the central U.S. The surface low formed over the Rockies and advanced across the plains into South Dakota by the late afternoon hours of the 6th. A cold front arched southeast and south of the low across central South Dakota into eastern Nebraska during the late afternoon hours. During the afternoon hours, the middle level dry slot raced north across Kansas, eastern Nebraska, into South Dakota. The surface showed an unstable weather situation. To the east of the cold front, which was actually more a dry line than a cold front, temperatures reached the upper 70s to lower 80s, with dew point temperatures in the lower to middle 60s. Dew point temperatures briefly reach 70 at a few locations during the early evening hours. Behind the dry line, dew point temperatures dropped to the upper 30s and 40s, with a few upper 20s in under the core of the dry slot. Directional sheer was weak, however a strong speed sheer existed. Lifted indices were around -5° C with a nearly 80 kt wind speed in the middle levels. Helicity values increased to around 350 M2/S2 in the pre-storm environment. A line of thunderstorms fired up during the mid to late afternoon hours. The storms quickly became severe as they moved into western Iowa. The hardest hit area was the west central counties where many areas were pelted with large hail. Monona and Crawford Counties were especially hard hit as a series of severe storms moved northeast along the main line of storms. There were numerous reports of golf ball size hail. One storm produced baseball size hail as it passed over the Ute area of Monona County. Baseball size hail also fell a short time later east of Soldier. WSR-88D radar VIL values with this storm were in the 60-65 Kg/M-2 range with the storm. A deep meso circulation was detected over northern Shelby and southern Crawford Counties with one of the storms. A tornado warning was issued. A funnel cloud was reported east of Defiance in Shelby County. It became a tornado briefly south of Manilla near the Shelby/Crawford County line. It passed through fields, causing some crop damage. The tornado dissipated with only a funnel cloud remaining as it passed over Manilla. A short time earlier, these storms produced golf ball size hail southeast of Earling in Shelby County. One farmstead reported 5 windows being broken out by the hail. Siding on the house was also damaged. The storms weakened as the moved east during the early evening. As the line advanced, a weak bow echo formed along the line. This bow echo produced gusty winds of 55 to 60 MPH as it passed over Webster, Boone, Wright, and Winnebago Counties. Damage was minor, however many trees were downed. The roof of one building was blown off and strewn across a field near Gowrie in Webster County. Part of a roof was torn off of a shed at Forest City in Winnebago County. The roof was removed from another farm building on a farmstead near Stacyville in Mitchell County. Damage was also reported west of Pilot Mound and north of Ogden in Boone County. High winds destroyed a 60 X 100 foot farm building on a farm north of Ogden. Damage on that farm was close to $50,000. The storms continued east but weakened slightly. Winds of 40 to 55 MPH were common, however the storms remained below severe levels through the rest of the night.