Flood — Cass, Iowa

1998-06-14 to 1998-06-16 · Cass, Iowa

Wider weather episode

After a brief lull from the rain on the 12th, a large mesoscale convective system developed near the center of an upper level low pressure center over southwest Iowa during the early morning hours of the 14th. Extremely heavy rain fell over southwest and central Iowa from this storm. The rain gage at Atlantic had a 24 hour total rainfall of 13.18 inches. This established a new official record for the greatest amount of rainfall in a 24 hour period. Cass County was covered by a large area of 4 to 8 inch rains, which essentially submerged the entire county. The east Fork of the Nishnabotna at Atlantic 5 SW crested on the 15th at 22.36 feet, missing the all-time record set in September, 1972 by about one half foot. Very heavy rains also fell on the Raccoon and South Skunk river basins, with widespread 2 to 4 inches rains resulting in widespread flooding. Many areas within these basins were under flash flood warnings which subsequently evolved into river flooding. Both the north and south branches of the Raccoon River flooded. The crest at Redfield was the 4th highest crest on record. The flood waves from both rivers merged on the mainstem Raccoon to create the 2nd highest crest on record at both Van Meter and at Fleur Drive. Only the great floods of 1993 created higher crests. In addition, the Des Moines River at SE 6th St. in Des Moines crested at the 4th highest crest of record. Damage was widespread across the state with numerous basements flooded and crops washed out. At this point, thoughts of the flood of '93 were on many peoples minds as Iowa had not experienced flooding of this magnitude since the great floods of '93. The main rivers affected by this flood episode were the Iowa, Squaw Creek, Raccoon, Beaver Creek, Chariton, and East Nishnabotna.

Source: NOAA Storm Events Database, event_id 5653139. Narrative written by the NWS forecast office that issued the report.