After a long and snowy winter, March temperatures in the Midwest warmed dramatically. This caused the deep snowfields to melt quicker than normal. Plans were made for the high waters, which were sure to come. They didn't have to wait long.
On March 31, the Floyd rose to a 20.3 crest north of town. This was the highest in fifteen years. The Springdale area had to be evacuated. The storm sewers back up, causing flooding along Stueben Street and south to the Soo's ballpark. Things were about to go from bad to worse. The Missouri River was also on the rise.
In early April, predictions of a possible 17-foot depth were made. South Sioux City, in particular, was very nervous. The citizens began watching their levees, which protected the city from the river's rise. The levees were built to hold back the river to a depth of 19.4 feet. Then, the full extent of the problem was learned. The new prediction was for the Missouri to rise above the previous prediction, all the way to 22 feet. Riverside residents were warned to evacuate due to the rise, which would have them in "water to their waists".
South Sioux City was in deep trouble. Levees were two and a half feet lower than the expected crest, and leaks had already sprung. Patrolling the levees, repairing leaks, and sandbagging the tops went on for days.
In Sioux City water crept over Gordon Drive and flooded businesses to the east. The city built a four foot high earthen wall around the newly constructed city auditorium. The news then got worse. The prediction for the crest was increased to 24 feet.
Finally the levee west of South Sioux City collapsed and all the land between the river and Crystal Lake was covered with river water. When the river crested April 14 at 24.3 feet, it had pushed the Sioux River out of its banks flooding Riverside Boulevard and from Goldie Avenue south to Riverside Park. All business came to a standstill. The stockyards were closed, the packing plants damaged, and the sewer system taxed to it's limit. All of South Sioux City lay under water. Nearly the entire population was evacuated.
When the river subsided, the damage could be assessed. The monetary damage was estimated at $3,264,000. This figure does not take into account the toll of human suffering that took place with the devastating damage done to people's homes in both Sioux City and South Sioux.