Tornado and Flash Flooding in Iowa, June 23 to 24, 1998

Once again, a warm frontal boundary was located to the south of Iowa with very warm and unstable air just to the south of the front. Dew point temperatures were in the low 70s in the warm air. This moisture was drawn north over the frontal boundary, into Iowa. A large mesoscale convective system developed over northwest Iowa and moved east during the evening hours. Initially, the system produced hail over an inch in diameter, but the main severe weather associated with the storms was high winds. Some building damage was reported in Palmer in Pocahontas County. A grain bin was damaged by high winds in Humboldt in Humboldt County. Windows were blown out at a mall department store in Webster County at Fort Dodge. Winds of 65 to 80 MPH were common in many areas. Wind damage on a farm near Clear Lake allowed a herd of cattle to escape. A man driving a van on U.S. highway 18 hit and killed six of the cattle. Damage from around the Clear Lake area was placed at nearly $1,000,000. High winds in Hancock County caused extensive damage on a farmstead north of Britt. The barn, several out buildings, and two cars were destroyed along with damage to the farm house as well. There was also one brief tornado touchdown in Calhoun County northeast of Lytton. Little damage occurred as it touched down in open country. As the storm advanced, high winds blew toward the Manson area. Damage was extensive from west of the town into the city of Manson. Numerous buildings were damaged by the high winds and several outbuildings and barns were nearly destroyed. The other major concern was with flooding. Iowa soil was nearly saturated at the time when heavy rainfall ensued. Rainfall of 3 to 4 inches in less than two hours was reported in Calhoun County. Numerous roads were closed by high water and knee deep water was reported in much of the town. Three to five inches of rain occurred in Sac and parts of Kossuth Counties as well. Most of the other areas where flash flooding was reported received 2 to 3 inches of rain in less than three hours. As thunderstorms moved across Carroll County, lightning struck a house in the town of Glidden. Appliances were damaged, power was knocked out, and part of the house was knocked off of its foundation.