| F5 tornado | |
|---|---|
 Damage from the F5 tornado that struck Rochester, Minnesota | |
| Formed | August 21, 1883, 6:30 p.m.CDT (UTC−05:00) |
| Dissipated | August 21, 18839:30 p.m.CDT (UTC−05:00) |
| Max. rating1 | F5 tornado |
| Fatalities | ≥ 37 deaths, ≥ 200 injuries |
| Damage | $700,000 (1887USD)[nb 1] $24.5 million (2025 USD) |
| Areas affected | Dodge andOlmsted Counties,Minnesota (particularly the city ofRochester) |
Part of theTornado outbreaks of 1883 1Most severe tornado damage; seeFujita scale | |
On August 21, 1883, a violent and devastatingtornado affectedsoutheastern portions of theU.S. state of Minnesota. The massive tornado, retrospectively estimated to have been anF5 on the modernFujita scale,[nb 2] caused at least 37 deaths and over 200 injuries. The tornado was part of atornado family, a series of tornadoes produced by asupercell, that included at least two significant tornadoes across Southeast Minnesota on August 21. A third significant tornado occurred two hours before the main event hit Rochester. The Rochester tornado indirectly led to the formation ofSaint Mary's Hospital, now part of theMayo Clinic. The tornado closely followed destructive tornadoes a month earlier in the same area: on July 21, twosignificant, deadly tornadoes hit the area, including an F4 tornado family that killed four people in Dodge and Olmsted Counties, especially nearDodge Center.[6][7]
On the morning of August 21, amid-latitude, deepeninglow-pressure center moved east-northeastward toward Minnesota, crossing the state during the afternoon and evening. The following morning, the cyclone had already deepened to at most 29.42 inHg (996 mb), suggesting a robust system on the preceding day. At the time,surface weather data from theUpper Mississippi Valley were sparse, but nearby observations in the afternoon indicated high temperatures in the middle 80s to low 90s °F. Eyewitnesses reported very humid conditions, indicating ample moisture forthunderstorms to develop.[8] As author Joseph Leonard mentioned in theHistory of Olmsted County, Minnesota,
At Rochester the day had been hot with a strong southeast wind, the air was smoky and oppressive, the heavens were overcast with clouds of a dull leaden line, and there were, apparently, three strata, all moving in different directions.[9]
Although meteorology in 1883 was primitive compared with modern science, Leonard's observations and other weather reports reveal quite a bit about the atmospheric conditions in Southeastern Minnesota on August 21. Hightemperatures, sufficienthumidity, strong surfacewinds, and verticalwind shear appear to have all been present—all of which are key factors in thedevelopment of tornadoes.[8]
| FU | F0 | F1 | F2 | F3 | F4 | F5 | Total |
|---|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 2 | 0 | 1 | 3 |
| "FU" denotes unclassified but confirmed tornadoes. | |||||||
By 4:00 p.m.CDT (21:00 UTC), light rain began falling over the area, and at 4:30 p.m. CDT (21:30 UTC), a thunderstorm spawned an F3 tornado about 10 mi (16 km) south of Rochester, nearPleasant Grove. The tornado killed two people, injured ten others, and damaged at least four farmsteads, one of which it destroyed. After the passage of the storm, conditions briefly improved. At about 6:00 p.m. CDT (23:00 UTC), residents of Rochester noticed a "low bank of cloud"—a thunderstorm—southwest of the city. Few residents were alarmed, but the storm rapidly grew in size and intensity as time passed.[10][6][11]
The Rochester tornado first touched down at about 6:30 p.m. CDT (23:30 UTC), approximately 4 mi (6.4 km) northwest ofHayfield in Dodge County. The tornado damaged farmsteads inWestfield,Hayfield,Ashland,Vernon, andCanisteo townships. In all, the tornado passed through 40 farms across Dodge County, at least 10 of which it razed, killing five or more people.[12][6][13]
As it entered Olmsted County, the tornado obliterated farmhouses, outbuildings, and machinery inSalem Township, causing one death.[14] The tornado continued to destroy structures on farms inKalmar,Cascade, andRochester townships before entering the city of Rochester itself. Heavy rainfall preceded the tornado.[11][6][9]
Just after 7:00 p.m. CDT (00:00 UTC), skies in Rochester assumed a greenish tint, and a rumbling sound became audible. The "roar" of the tornado gave many residents advance warning. "Dense darkness" enveloped the city as the tornado struck. In just five minutes, the tornado passed through the north side of Rochester, causing devastating damage. The northern third of Rochester was devastated, with 135 homes destroyed and 200 damaged. The tornado also caused extensive damage to a 1-mile-wide (1.6 km) swath that extended 10 mi (16 km) eastward from Rochester.[15][6][13]
At 9:30 p.m. CDT (02:00 UTC), a final tornado, given an F3 rating upon retrospective review, killed one person and injured 19 others nearSt. Charles andLewiston inWinona County.[6]
The city of Rochester did not have a place to treat the injured from this tornado, as all but three of Minnesota'shospitals were located inMinneapolis–Saint Paul at that time, and none of the remainder was sited near Rochester. Following the tornado, a dance hall in Rochester,Rommel Hall, served as a makeshiftemergency room. Local doctors assumed responsibility for the patients' wellbeing under the direction of Rochester Mayor Samuel Whitten;Mother Mary Alfred Moes of theSisters of St. Francis cared for the patients. Subsequently, the Sisters of St. Francis establishedSt. Mary's Hospital, which ultimately yielded theMayo Clinic and later theTornado Guild, the latter of which was dedicated to tornado preparedness.[16][7]
