Fort Snelling and Smithsonian Observers (1820-1870)
The first official weather observations in the present day Twin Cities area were taken by U.S. Army staff who set up a fort at the confluence of the Minnesota (known as St. Peter at the time) and Mississippi rivers in August of 1819. Fort Snelling, as the installation would be known after its completion in 1824, orginally began as a log hut and tent city along the Minnesota River bottom, 100 feet below the present day bluff location.
Map of the present day Minneapolis-St. Paul region in 1850, including the location of Fort Snelling at the Confluence of the Minnesota (St. Peter) and Mississippi rivers near the bottom left corner (Courtesy of the Minneapolis Public Library, Minneapolis Collection, Maps)
Members of the surgeon general staff were asked to take weather observations at the newly establised fort by the U.S. Army Chief Medical Officer because the Army was interested in the "effects of climate on the health of soldiers". The new "Northwest Frontier" was an ideal place to record weather since the winters were extreme by East Coast standards and no one really knew what to expect during each season at this new outpost.
The first known weather observation was taken in October of 1819 at the St. Peter (also known as "Cantonment New Hope") river bottom camp near the southeast end of the present day Mendota Bridge. The only records that survive from October, November, and December of 1819 are monthly means. Starting in January of 1820, the records of daily weather observations, notarized by the Surgeon General of the post, Edward Purcell, have been located.
The records show that the Army camp and observation site was moved in May of 1820 to a location across the river which was northwest of the present day site of Fort Snelling. The weather diary has a data gap between May 21st and 23rd with the notation, "moving from St. Peter's to Cold Water Camp." Between the move to Cold Water Camp and the completion of Fort Snelling in 1824 the exact location of weather observations is unknown. However, it is known that the instruments were moved at least 3 times during this period and that observations were taken at both river bottom and hilltop locations near the present day fort.
Fort Snelling as seen from the east shore of the Mississippi River bottom in 1867
(Courtesy of the Minneapolis Public Library, Minneapolis Collection)
Temperature observations between January of 1820 and December of 1835 were recorded at 7 AM, 2 PM, and 9 PM using Army issued instruments that had a good reputation for accuracy at the time. Highs and lows during this period were calculated by present day scientists using formulas of the normal diurnal rise and fall of temperatures based on local climate trends. Wind and sky cover information was noted only once daily and was recorded in qualitative form. Sky cover was recorded as either "cloudy" or "fair" and occasionally precipitation type and intensity was also noted. Wind speed observations were similar to present day Beaufort scale notations such as calm, light breeze, gale, and storm.
Between January of 1836 and December of 1855, temperature observations were taken at slightly different times based on Army regulations but generally occurred around sunrise, early afternoon, and sunset. Highs and lows were also estimated using diurnal formulas based on historical climate trends. Wind and sky cover information continued to be recorded qualitatively. Most notably quantitative precipitation data began to be recorded in January of 1837.
In Janary of 1856 the weather observation site was moved from Fort Snelling to the downtown Minneapolis office of the Army Medical Department. Dr. C. L. Anderson who was located at the corner of Helen and 2nd St. was in charge of recording weather conditions during this time.
On December 31, 1858 the Army stopped taking weather records in Minneapolis, so the weight of recording daily observations fell onto the shoulders of local volunteer Smithsonian Institution weather observers. Between January of 1859 and December of 1870 the data recorded by the official St. Paul Smithsonian observer, Reverend A. B. Paterson, was used to complete the climatological record. His observations were made daily at 7 AM, 2 PM, and 9 PM and included temperature, sky condition, and wind direction. In addition, wind speed was qualitatively recorded using guidance from the Smithsonian.
In 1862, the Smithsonian also recruited a volunteer observer in Minneapolis. The city coroner, William Cheney, who was located at the corner of Douglas and Freemonet St., recorded weather observations through June of 1901. Although the St. Paul observations were used for the official Twin Cities record during the period, the records taken in downtown Minneapolis during this time are a treasured data source.