July 4, 1876 -- Deadliest Flood in Iowa's History

The deadliest known flood in Iowa's history occurred in Rockdale, IA on July 4, 1876.

Rockdale is now a community located entirely within the City of Dubuque—on the town’s southern side. In 1876 Rockdale was a village located between Dubuque and Key West, Iowa. It was also divided by a ravine through which Catfish Creek flowed toward the Mississippi River around two miles downstream. Rockdale was located along the main vehicle route going south of Dubuque. It was also home to one of the area’s first flour mills.

The flood occurred on July 4, 1876 when heavy rain caused Catfish Creek to swell and break the dam upstream of town at the Rockdale Mill. The resulting wall of water was around 20 feet deep and hundreds of feet wide as it swept into town.

Around 40 people—nearly every person in town—perished in the flood. The few survivors were found in treetops where the floodwaters had swept them. Only two buildings were left standing—the Rockdale Mill and one house. The village lost a saloon, hotel, two stores, a Post Office, several houses and a blacksmith shop.

One of the most amazing stories of survival involves Charles Thimmesch, a barkeeper. After warning others about the flood he climbed to the roof of the Post Office. He eventually swam naked to higher ground with his money clenched in his teeth.

This image is an antique woodcut engraving titled “Iowa-The Disastrous Flood at Rockdale on the Night of July 4th-5th. Scene Near the Dam the Morning After the Storm.” From a Sketch by A. Simplot. This photo was published in Frank Leslie's Illustrated Newspaper on July 29, 1876.

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