Tri-State Tornado Outbreak

On March 18, 1925, one of the deadliest tornado outbreaks in recorded history generated at least 12 significant tornadoes and spanned a large portion of the midwestern and southern United States. In all, at least 751 people died, including men, women, and children. 2,298 were injured, making the outbreak the deadliest tornado outbreak in U.S. history. The outbreak generated several destructive tornadoes in Missouri, Illinois, and Indiana on the same day, as well as significant tornadoes in Alabama and Kansas. In addition to confirmed tornadoes, there were undoubtedly others with lesser impacts, the occurrences of which have been lost to history.

The outbreak included the Tri-State Tornado, the deadliest disaster in Illinois, the deadliest tornado in U.S. history, and the second-deadliest registered in world history.Tri-State Tornado
- History, Facts and Information The track left by the tornado, as it crossed from southeastern Missouri, through southern Illinois, and then into southwestern Indiana, is also the longest ever recorded. Modern meteorological re-analysis has suggested that the extremely long path length and lifespan reported in historical accounts are perhaps more plausibly attributed to multiple independent tornadoes belonging to a tornado family, rather than a single, continuous tornado. Although not officially rated by NOAA, the Tri-State Tornado is recognized by most experts (such as Tom Grazulis and Ted Fujita) as an F5 tornado, the maximum damage rating issued on the Fujita scale.

Background

During a six-year review study of the Tri-State tornado published in 2013, new surface and upper air data was obtained and meteorological reanalysis was utilized, adding significantly to knowledge of the synoptic and even mesoscale background of the event. The late winter to early spring of 1925 was warmer and drier than normal over much of the central United States. There apparently was persistent ridging in the western U.S. with a troughing pattern over the central U.S.

The extratropical cyclone that set the synoptic stage for the outbreak was centered over northwestern Montana at 7:00 a.m. CST (13:00 UTC) on March 17. Meanwhile, a diffuse area of surface low pressure was centered near Denver, Colorado, in association with a lee trough. Occluded fronts extended from Hudson Bay southwestward into the northern Plains states and into the lee trough. The synoptic cyclone moved south-southeastward across the mountain states to eastern Colorado. A warm front stretched along the Gulf Coast, separating warm, moist air from cool, showery weather with areas of fog that extended from Texas to the Carolinas. A well-mixed early-season continental tropical (cT) air mass existed over West Texas and northern New Mexico. To the east of this hot, dry air, buoyant maritime tropical (mT) air was advecting from the Gulf of Mexico. Simultaneously, a mid- to upper-level shortwave trough likely approached the northwest coast of the U.S. and moved rapidly through the persistent ridge then digging southeastward across the Great Basin and central Rocky Mountains and emerging in the Plains over Colorado. This initiated a " Colorado low" cyclogenesis.

At 7:00 a.m. CST on March 18, the surface low-pressure area, at approximately , moved to far northeastern Oklahoma while the warm front shot north into the circulation where the front then extended eastward. A maritime Polar (mP) cold front draped southwestward across eastern Texas with a dry line forming directly to the south of the low. The open shortwave, likely somewhat negatively tilted, was continuing to approach from the northwest and an apparent outflow boundary moved just to the south of the warm front over northeastern Arkansas and northwestern Tennessee. Several weak pressure troughs were traversing the cool sector over the north-central U.S.. Surface temperatures in the warm sector near the dry line and warm front ranged from , and the dew point was , with higher values farther south and increasing over time as the deepening low-pressure area continued to pull up air from the Gulf of Mexico. https://www.weather.gov/pah/1925Tornado_wi#:~:text=In This resulted in unstable air and lower cloud bases, or low LCL heights, which is favorable to tornadogenesis. From southeastern Kansas to Kentucky and Indiana, early morning showers and thunderstorms north of the low and warm front cooled and stabilized that air, retarding northward advancement of the front, and led to a sharp contrast in temperature from north to south. Such baroclinic zones are also associated with tornadic storms. Ahead of the surface dry line, which are uncommon as far east as the Mississippi River, an apparent " dry punch" of air aloft served to further increase instability. Concurrently, a capping inversion likely suppressed storms throughout the warm sector, leaving the Tri-State supercell undisturbed by nearby convection.

By 12:00 p.m. CST (18:00 UTC), the deepening surface low was centered over south-central Missouri, the shortwave axis was moving easterly and oriented over eastern Oklahoma, and the dry line was rapidly advancing eastward directly south of the low as the warm front, situated due east of the low, slowly shifted northward. Morning clouds cleared by midday across much of the Tri-State tornado's eventual path. A pronounced pressure trough extended northeast of the low and signaled its future track as a prefrontal trough formed southeast of the low ahead of the dry line. A bulge in the dry line may also have been forming slightly south of the low, and southerly to southeasterly surface winds were backing and increasing with time throughout the warm sector. The Tri-State supercell formed in a highly favorable area just ahead of the triple point where the cold front, warm front, and dry line met. The supercell initiated very near the surface low and moved east-northeastward, faster than the low, such that the storm gradually deviated east of the low's track. The supercell remained near this "sweet spot" for a prolonged period as it also traveled near the highly baroclinic warm front (likely just across the cool side of the boundary) for several hours.

By 2:00 p.m. CST (20:00 UTC), the low was centered slightly south-southwest of St. Louis, Missouri, as the Tri-State supercell neared the Mississippi River. Other storms in the warm sector, removed from the Tri-State supercell, were initiating around 3:00 p.m. CST (21:00 UTC). Around 4:00 p.m. CST (22:00 UTC), the low's central pressure lowered to around , centered over south-central Illinois, as the supercell was moving into Indiana. This pressure is not particularly low compared to many other outbreak setups, but the pressure gradient was strong, which induced strong gradient winds and significant advection in the warm sector. A very strong low level jet was also in place just above the surface as winds veered with height, resulting in low-level curvature and long hodographs. Strong wind shear thus existed, with pronounced directional shear likely in the vicinity of the warm front, with winds at the 700 hPa height level west-southwesterly around and winds at the 500 hPa level about . Theoretical hodographs returned estimated storm relative environmental helicity (SREH) values of 340 m² s⁻² in the vicinity of the Tri-State supercell track. Strong thunderstorms were now scattered throughout the warm sector and a line of severe thunderstorms was occurring near the dry line. The Tri-State supercell appeared to still be discrete and isolated, with a severe storm north of Cairo, Illinois, placed well to its south.

By 6:00 p.m. CST (00:00 UTC), the shortwave axis was over eastern Missouri and was lifting northeast. At 7:00 p.m. CST (01:00 UTC), the low was placed near Indianapolis, Indiana, with numerous thunderstorms east and south of the low and a squall line moving into the southeastern U.S. Cold air advection behind the strong cold front fed into the cyclone as snow and sleet fell from eastern Iowa to central Michigan. At 7:00 a.m. CST on March 19, the low was deepening and lifting rapidly northeastward into Canada.

Confirmed tornadoes

These are estimated tornado ratings as tornado ratings in the United States were not official until 1950.

Tri-State tornado

The tornado, sometimes referred to as the Great tri-state tornado, touched down around 1.00 pm in Shannon County, Missouri, moving to the northeast. The tornado immediately began to produce heavy damage to structures before directly impacting Annapolis, destroying ninety percent of the town and killing two people. The tornado then moved through Bollinger County, where it would hit two schools and injure several children who were taking shelter. Deep ground scouring was observed as the tornado moved past Sedgewickville, and debris from the town was found almost away. It would hit several other small communities, including Brazeau and Frohna, before crossing state lines into Southern Illinois and directly impacting Gorham. Over half of the town's population was killed, and the town was devastated as the tornado moved by. To the northeast, it would hit the northern portions of Murphysboro, where over one hundred residents would die as the tornado barelled through the town at an estimated forward speed of .

Further east, the tornado crossed into Franklin County, narrowly missing the towns of Royalton and Zeigler, devastating rural areas before heading towards the large mining town of West Frankfort. The tornado struck the northwest side of town, where in a manner similar to what was seen at Murphysboro, a number of densely populated neighborhoods, businesses and mining operations fell victim to the tornado. At the Peabody Mine 18 in Caldwell, a large 80-foot coal tipple weighing several hundred tons was blown over and rolled by the tornado. The tornado proceeded to devastate additional rural areas across Hamilton and White counties, between the two counties claiming 45 lives and injuring 140, 20 of whom later died, where it dissipated over three hours after touching down.

The tornado killed at least twenty farm owners in southeastern Illinois and southwestern Indiana, more than the combined total of the next four deadliest tornadoes in the history of the United States. The tornado killed a combined total of 695 people, the majority of which occurred in Illinois. Despite not being officially rated, it is widely accepted to have been equivalent to an F5 on the Fujita scale, with winds up to . There has long been uncertainty as to whether the originally recognized reports of a path over 3.5 hours represent a single continuous tornado or multiple independently tracking tornadoes belonging to a tornado family. Because of the scarcity of verifiable meteorological data from the time of the event and the apparent absence of any record of a tornado having approached this path length and duration in the years since, doubts have been raised about the plausibility of the conclusion that a single tornado was responsible for them. To date no definitive conclusion has been reached and a complete understanding of what occurred remains unachieved.

Non-tornadic effects

Strong thunderstorms were reported in a broad area that also included parts of Oklahoma, Michigan, Pennsylvania, West Virginia, and Ontario. Numerous reports of hail and straight-line winds were reported, with up to hail recorded (by comparison, a softball is in diameter). What began in the early afternoon as discrete supercell thunderstorms eventually consolidated into a potent squall line. By all accounts it was a widespread outbreak with severe thunderstorms occurring as far east as Ohio, as far southwest as Louisiana, and as far southeast as Georgia.

See also

*List of tornadoes and tornado outbreaks
**List of North American tornadoes and tornado outbreaks
*List of tornado-related deaths at schools
*List of F5 and EF5 tornadoes
* Tornado outbreak sequence of December 18–20, 1957 – Produced another violent tornado that paralleled the Tri-State tornado in Illinois.
*Daulatpur–Saturia tornado – Deadliest tornado worldwide in recorded history that struck Manikganj District in Bangladesh on April 26, 1989.
*Tornado outbreak of December 10–11, 2021 – Another deadly tornado outbreak that contained the "Quad-State supercell", which was initially believed to have dropped a single tornado that tracked over 4 states, but was later found to have not done so.
*Tornado outbreak of March 13–16, 2025 – A tornado outbreak which affected many of the same areas in March of 2025, just a few days shy of Tri-State's 100th anniversary.

Notes

References

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External links

1925 Tri-State Tornado
(NWS Paducah, KY)


* ttps://web.archive.org/web/20081016135615/http://www.rootsweb.com/~ilfrankl/subjects/tornado.htm The Great Tri-State Tornado(RootsWeb Genealogy)

The 1925 Tornado
(Carolyar.com Genealogy)

Aerial film of damage path

'The 1925 Tri-State Tornado Damage Path Analysis' By R.H. Johns & Associates

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