Comparisons to past floods
The 1997 spring floods on the Minnesota River above New Ulm and on the entire Red River of the North established many new records. Grand Forks/East Grand Forks experienced major urban flood damages when the cities' emergency dikes were overtopped. The current estimate of commercial building and inventory losses in Grand Forks alone is about three-quarter of a billion dollars. Compared to other floods in this area during this century, the 1997 spring flood was unprecedented. The graph on page 4 shows the highest annual instantaneous discharges recorded on the Red River of the North at Grand Forks since 1882.
Records of past floods are used to estimate the probability of equal or greater floods in the future. Unfortunately, flood records on major river are poor or nonexistent prior to 1900. Records on smaller rivers and streams are even more limited. This lack of good long-term records makes flood frequency analysis difficult. One way of supplementing recorded flood information is to look for other evidence of past floods, such as written observations found in reports, journals, diaries and newspaper articles. An example of this type of information for the Red River of the North is contained in the April 1897 edition of the U.S. Department of Agriculture publication titled "Climate and Crops: Minnesota Section". This publication summarized Minnesota climate data and discussed climate issues.
The April 1897 issue was published when the Red River of the North was experiencing a severe flood, and it drew on anecdotal information about earlier Red River basin floods. The accounts provide support to the argument that extreme flood events in large river basins result from extreme climatic conditions and not from the actions of man.