Photo Gallery 3 Images
National Weather Service La Crosse -- Just a few days after the massive flood event June 30-July 1, a more concentrated heavy rainfall event occurred from Dodge county east to Winona county, with the heaviest band of 6 to 7 inches just south and east of the Rochester area. The National Weather Service (NWS) gage at Rochester International Airport measured 4.99" in 3 hours (between 5:53 p.m. and 8:53 p.m.) on the July 5th. Precipitation ended around 1:50 a.m. on the July 6th. The total rainfall at Rochester International Airport was 6.74 inches. The heaviest amount, 7.30 inches, occurred in Quincy Township in eastern Olmsted County. The 4-inch or more rainfall band was about 12-15 miles wide and 74 miles long and covered 700 square miles. The South Fork Zumbro River and it’s tributaries (Bear Creek, Silver Creek, Cascade Creek) went into flood through Rochester causing extensive damage.
Rivers started rising during the evening and continued at a foot per hour during the night. The July 6th crest (at 10 AM) at the Rochester river gage (on the south fork of the Zumbro River) established an all-time record of 23.36 feet (flood stage 12 feet) and 30,500 cfs, easily exceeding the previous record crest (1965) by over 4 feet. This flood and yet another on September 12, 1978 prompted the construction of a major flood control project by the U.S. Army Corps of Engineers and the Natural Resources Conservation Service in and around Rochester. This project was completed in 1995, at a cost amounting to $92 million and protects the city against a 200-year recurrence interval flood event.
This flood was considered Rochester's worst natural disaster in almost 100 years and the worst flood in the city's history. One fourth of city, mainly south and northeast sections, was inundated by turbulent flood water 6 feet deep or more. Four persons (a nurse's aide and 3 wheel chair patients) in nursing home were trapped in an elevator and drowned. A fifth person died when her car plunged off County Road 10 southwest of Rochester. Nearly 5,000 residents were forced to evacuate. Dozens of campers at Whitewater and Beaver Creek State Parks were evacuated. Flood waters carried tons of uprooted trees and other debris through downtown Rochester. Several bridges were swept away. Many cars were overturned or swept away. Some were carried for blocks. Basements flooded, a few with water above the first floor with some foundations collapsing. Power and telephone lines were out in central Rochester with no traffic lights in operation. Eighty percent of the city estimated without power with generators under water. Many businesses and shopping centers were closed due to flooding and lack of electricity to operate computers and cash registers. Sewage treatment plant was out of commission. The pictures below show some of the flooding in Rochester (these were from the city of Rochester).
In addition 2 to 3 inch rains fell over the headwaters of the Cedar River in Mower and Dodge counties, which produced significant flooding. Besides causing significant to record flooding, it set the stage for a more important event 10 days later.
The map below is from the Minnesota State Climatology Working Group and it shows the precipitation totals from July 5-6, 1978 in southeast Minnesota. It was prepared using 64 Future Farmer of America reports and 16 National Weather Service reports.