Minnesota is no stranger to floods caused by heavy precipitation. The city experiences rainfalls of such high magnitudes with a large geographical extent capable enough of becoming catastrophic.
Since statehood, there have been several mega-rain events that have occurred in Minnesota. The mega-rains have brought floods with six inches of water, which covered over 1000 square miles of land. Research from historical climate records, diaries, and newspaper accounts have proven to be very beneficial in identifying the next floods.
However, it wasn’t always like this until the ambitions and foresight of the State Climatologist Earl Kuehnast and Dr. Don Baker in the 1970s. Their desire to study the flash floods caused by heavy rainfalls impacted an explosion of rainfall observers. Since then, the state of Minnesota has undoubtedly avoided some significant destruction and water damage caused by the floods.
Although their system has experienced some changes over the years, it has remained intact for the core purpose of identifying mega-rainfall events.
The spring flooding of 1965 started with cold and snow but later on escalated into a widespread of heavy rainfall. The rainfall was experienced along the Minnesota, Mississippi, and St Croix rivers. The damage occurred across the five-state areas of Minnesota, Wisconsin, Illinois, Lowa, and Missouri. The flash floods claimed 15 lives, injured over 600 people, and damaged over 11,000 homes.
July 17-19, 1867: This is considered Minnesota's most hazardous flash flood for over 200 years. The flash floods occurred in Central Minnesota, where torrential rains fell relentlessly. In less than 40 hours, observers at that time were able to pinpoint about 30-36 inches of heavy rainfall. Up until now, there hasn't been any such observation by the state's official observers. It is mostly referred to as Minnesota's Greatest Thunderstorm.
September 9-10, 1947: This flood caused extensive damage over the Iron Range district. Within 24 hours, a total of 6 inches was recorded at Winton, Ely, and Hibbing.
June 21, 1983: During this time, torrential rains fell slowly and flooded five counties. The recorded totals by official observers stood at 8 inches and covered parts of the five counties: Litchfield, Paynesville, Buffalo, Clearwater, and Big Lake.
August 18-20, 2007: In the footsteps of the 1867 storm, these Southern Minnesota flash floods produced 15.10 inches, making it the highest recorded total in 24 hours.
June 19-20, 2012: The two day total at Duluth was 7.24 inches. The St. Louis River at Scanlon set a new record crest at 16.62 feet, rising 10 feet in 24 hours.