Tri-State Tornado

Tri-State Tornado Outbreak

Newspaper coverage of the tornado
Type	Tornado outbreak
Duration	Wednesday, March 18, 1925
Tornadoes confirmed	12 known
Max rating1	F5 tornado
Duration of tornado outbreak2	7 hours
Largest hail	4.5 inches (11 cm) at Lexington, KY at 7:15 pm CST[1]
Damage	>$1.4 billion (1997 USD)[2] (Tri-State Tornado only)
Casualties	747+ (695+ from one tornado) fatalities, >2,298 injuries[3]
Areas affected	Midwestern and Southeastern US
1Most severe tornado damage; see Fujita scale 2Time from first tornado to last tornado

The Tri-State Tornado of Wednesday, March 18, 1925 was the deadliest tornado in U.S. history.^[4] It was also the most exceptional tornado during a major outbreak of at least twelve known significant tornadoes spanning a large portion of the Midwestern and Southern U.S. The tornado alone inflicted 695 fatalities,^[5] more than twice as many as the second deadliest, the Great Natchez Tornado of 1840. The 151 to 235 mi (243 to 378 km) track left by the tornado was the longest ever recorded in the world as it crossed from southeastern Missouri, through southern Illinois, then into southwestern Indiana.^[6] Although not officially rated by NOAA, it is recognized by most experts (such as Tom Grazulis^[7] and Ted Fujita^[8]) as an F5 tornado, the maximum damage rating issued on the Fujita scale.^[3]

Tornado outbreak

The tornado was part of a larger tornado outbreak with several other destructive tornadoes the same day in Tennessee, Kentucky, and Indiana, as well as significant tornadoes in Alabama and Kansas. Including additional tornadoes that day, at least 747 people were killed and more than 2,298 were injured. This makes the Tri-State Outbreak the deadliest tornado outbreak, March 18 the deadliest tornado day, and 1925 the deadliest tornado year in U.S. history.^[9] There were undoubtedly other less impactful tornadoes, the occurrences of which have been lost to history.^[3]

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. Strong thunderstorms were reported in a broad area that also included parts of Oklahoma, Michigan, Ontario, Pennsylvania, and West Virginia. Numerous reports of hail and straight-line winds were reported with up to 4.5 in (11 cm) diameter hail recorded (for reference, a softball is 3.5–3.8 in (8.9–9.7 cm) in diameter^[10]). What began in early-mid afternoon as discrete supercell thunderstorms eventually consolidated into a potent squall line.^[1]

Meteorological synopsis

Tri-State Tornado storm track and other tornadoes that day from Monthly Weather Review, April 1925.^[11] The information about the temperature, pressure, and other tornadoes may not be accurate.

During a six-year review study of the Tri-State Tornado published in 2013, new surface and upper air data to analyze were 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 US with a troughing pattern over the central US.^[1]

The extratropical cyclone that would set the synoptic stage for the outbreak was centered over northwestern Montana at 7 am CST on March 17. Meanwhile, a diffuse area of surface low pressure was centered near Denver, Colorado in association with a lee trough. Occluded fronts lay 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 US 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 "Colorado low" cyclogenesis.^[1]

At 7 am on March 18, the surface low-pressure area at ≈1,003 hPa (29.6 inHg) moved to far northeastern Oklahoma and the warm front had 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 due 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 south of the warm front over northeastern Arkansas and northwestern Tennessee. Several weak pressure troughs were traversing the cool sector over the north-central US. Surface temperatures in the warm sector near the dryline and warm front ranged from 65–75 °F (18–24 °C) and the dew point was 60–65 °F (16–18 °C), with higher values farther south and increasing over time as the deepening low-pressure area continued to pull up Gulf air. 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 sharp contrast in temperature from north to south. Such baroclinic zones are also associated with tornadic storms. Ahead of the surface dryline, which are not common as far east as the Mississippi River,^[12] 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.^[1]

By 12:00 pm, the deepening surface low was centered over south-central Missouri, the shortwave axis was moving easterly and oriented over eastern Oklahoma, and the dryline was rapidly advancing eastward directly south of the low as the warm front slowly shifted northward situated due east of the low. Morning clouds cleared by midday across much of where the Tri-State Tornado would track. 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 dryline. A bulge in the dryline 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 dryline met. The supercell initiated very near the surface low and moved east-northeastward and 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.^[1]

By 2 pm, the low was centered slightly south-southwest of St. Louis, Missouri as the Tri-State supercell was near the Mississippi River. Other storms in the warm sector, removed from the Tri-State supercell, were initiating around 3 pm. Around 4 pm, the low's central pressure lowered to around 998 hPa (29.5 inHg) centered over south-central Illinois as the Tri-State 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 70 mph (110 km/h) and winds about 90–110 mph (140–180 km/h) at 500 hPa. 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 dryline. The Tri-State supercell appeared to still be discrete and isolated, with a severe storm north of Cairo, Illinois placed well to its south.^[1]

By 6 pm, the shortwave axis was over eastern Missouri and was lifting northeast. At 7 pm, the low was placed near Indianapolis, Indiana with numerous thunderstorms east and south of the low and a squall line was moving into the southeastern US. 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 am on March 19 the low was deepening and lifting rapidly northeastward into Canada.

The Tri-State supercell is thought to have formed around noon about 40 minutes prior to the first tornado reports in Shannon County. It was a classic supercell for the first couple hours of its life, gradually transitioning into a high precipitation (HP) supercell in southern Illinois. The very long track tornado period lasted from around 12:40 pm to 4:40 pm. The supercell then likely produced another significant tornado in southeastern Indiana around 6 pm. Convection had gradually increased in the warm sector throughout the supercell's life cycle. It may have become embedded within a line echo wave pattern (LEWP) by the time it reached south-central Indiana. The supercell is assumed to have decayed around 7 pm. These estimated times indicate the supercell's duration as around 7 hours over a calculated ≈413 mi (665 km) path.^[6][1]

Single tornado or a series?

There has long been uncertainty as to whether the originally recognized numbers of a 219 mi (352 km) path over 3.5 hours was one continuous tornado or a tornado family. The sparse quality of tornado data because of the distance in the past and the lack of other tornadoes approaching the Tri-State Tornado path length and duration raised doubts. Furthermore, meteorological theory on tornado and supercell morphology and dynamics suggests such duration is highly improbable.^[1] In fact, several other historically very long track (VLT) tornadoes were subsequently found to be tornado families^[13] (notably the Woodward, Oklahoma tornado family of April 1947 and the Charleston-Mattoon, Illinois tornado family of May 1917). In the past several years some VLT tornadoes and supercells did occur with 12 tornadoes exceeding 100 mi (160 km) path lengths from 1980-2012 (and 60 since 1950).^[6] Yet the high end estimates of the Tri-State Tornado path length are still around twice as long as the nearest VLT tornado. On the other hand, meteorological analysis reveals no analogous event meaning that the Tri-State Tornado conditions were apparently unique.

Exhaustive research published in 2013 found no definitive resolution but did locate additional tornado sightings and damage 15 mi (24 km) west of the previously known beginning of the tornado and 1 mi (1.6 km) east of the previously known ending. The scientists conclude it is likely that some of the track both at the beginning and ending were indeed separate tornadoes. This segment of the probable tornado family is 235 mi (378 km) long. They also located a 20 mi (32 km) path (over about 20 min) from a large tornado which was likely spawned from the same supercell and was about 65 mi (105 km) east-northeast of the aforementioned path ending. This brings the known length of the Tri-State Tornado Family to around 320 mi (510 km) over nearly 5.5 hours. The 2013 study concludes that it is likely that the 174 mi (280 km) segment from central Madison County, Missouri to Pike County, Indiana is one continuous tornado and that the 151 mi (243 km) segment from central Bollinger County, Missouri to western Pike County, Indiana is very likely a single continuous tornado.^[6] The tornado path may have been longer but either of these values still hold the record for longest recorded tornado track. Grazulis in 2001 wrote that the first 60 mi (97 km) of the track is probably resultant of two or more tornadoes and that a path length of 157 mi (253 km) was seemingly continuous.^[14] No single factor accounts for the exceptional path length and duration. The fast forward motion of the tornado, which averaged 59 mph (95 km/h) translated to more distance covered.^[1]

Tri-State Tornado

Missouri

The tornado was first sighted as a highly visible and relatively small condensation funnel in the rugged forested hills of Moore Township, Shannon County, Missouri at about 12:40 pm.^[6] The first fatality occurred around 1:01 pm, north-northwest of Ellington by which the time the tornado was large. Several homes and other structures were destroyed north of town. The tornado sped to the northeast, causing $500,000 worth of property damage and the near annihilation of Annapolis, where much of the town was leveled, and two people were killed. The tornado then struck the mining town of Leadanna, where mining machinery and several structures were destroyed, and two other people were killed.^[15] In Bollinger County, 32 children were injured when two schools were damaged and multiple homes were completely destroyed. Deep ground scouring was observed near the town of Sedgewickville as well. The tornado carried sheets of iron as far as 50 mi (80 km) away. Crossing into Perry County, the tornado reportedly displayed a double funnel as it struck the town of Biehle, destroying many homes in and around the town, and killing four people. Numerous other homes were completely leveled near Frohna as well.^[15][16] The town of Cornwall was also hit by the tornado. At least 11 (possibly more) died altogether in Missouri.

Illinois

Ruins of the Longfellow School, Murphysboro, Illinois, where 17 children were killed. The storm hit the school at about 2:30 pm

The tornado crossed the Mississippi River into southern Illinois, debarking trees and deeply scouring the ground in rural areas before hitting the town of Gorham, at 2:30 pm, essentially obliterating the entire town, killing 34. Almost every structure in Gorham was leveled or swept away, and railroad tracks were reportedly ripped from the ground.^[15] More than half the town's population was injured or killed and seven fatalities occurred at a school.^[14] Continuing to the northeast at an average speed of 62 mph (100 km/h) (and up to 73 mph (117 km/h)), the tornado cut a swath almost 1 mi (1.6 km) wide through Murphysboro, completely flattening a large portion of the town. Entire rows of homes were leveled and swept away in some areas.^[17] Many other structures were also damaged or destroyed throughout the town, including the M&O railroad shop, where 35 people were killed. Schools in the area were devastated as well, with 17 students killed at the Longfellow School, and 9 others killed at the Logan School.^[15] After the tornado passed, large fires ignited and swept through the rubble, burning many of the trapped survivors alive.^[18] In Murphysboro, a total of 234 were killed, the most tornadic deaths in a single city in U.S. history.

The tornado then struck the nearby town of De Soto, which was also devastated. 69 people were killed in De Soto, and many homes were swept away. 33 of the deaths were students that were killed in the partial collapse of the De Soto School, the worst tornadic death at a single school in US history.^[18] The tornado continued northeast and impacted the small village of Bush, killing seven people there. Several homes were leveled, and pieces of wood were speared into the town's water tower. Heavy railroad axles were reportedly lifted and scattered across the railyard.^[18] Further east, the mining town of West Frankfort was also devastated by the massive tornado, with 152 fatalities occurring in that area. The tornado struck the northwest side of town, leveling many businesses and sweeping away entire subdivisions.^[15] At the Orient Mine, a large multi-ton coal tipple was blown over and rolled by the tornado. Extreme damage continued east of town, as a railroad trestle was torn from its supports, and 300 ft (91 m) of railroad track was ripped from the ground and blown away. Several small mining villages in the area were obliterated, resulting in numerous fatalities.^[17] The tornado then destroyed the small town of Parrish, where 22 people were killed, and the town was never rebuilt. Severe damage and several fatalities also occurred in the Olga area.^[15] Within 40 minutes, 541 lives were lost and 1,423 were seriously injured. The tornado proceeded to devastate rural areas across Hamilton and White counties, claiming 65 more residents before crossing into Indiana. An estimated 613 people died in Illinois, the most tornadic deaths within a state in U.S. history.

Indiana

Ruins of the town of Griffin, Indiana, where 26 people were killed.

Crossing the Wabash River into Indiana, the tornado struck and completely demolished all of Griffin, where most structures were leveled, and some were swept away. 26 people were killed there. The tornado then devastated rural areas, and clipped the town of Owensville, resulting in two fatalities in that town. The tornado then roared into Princeton, destroying half the town and killing 45 people. Large sections of neighborhoods in Princeton were leveled, and a Heinz factory was badly damaged.^[15] The tornado traveled more than 10 mi (16 km) to the northeast before finally dissipating at about 4:38 pm around 2.5 mi (4.0 km) south-southeast of Petersburg. In Indiana, at least 71 (and probably more) perished.^[19]

Total

In all, at least 695 died and 2,027 were injured, the majority in southern Illinois. Three states, thirteen counties, and more than nineteen communities, four of which were effectively effaced (several of these and other rural areas never recovered), were in the path of the record 3.5 hour duration tornado. Approximately 15,000 homes were destroyed by the Tri-State Tornado.^[20] Total damage was estimated at $16.5 million; adjusted for increases population/wealth and inflation the toll is approximately $1.4 billion (1997 USD), surpassed in history (through 2010) only by two extremely destructive tornadoes in the City of St. Louis in 1896 and 1927.^[2]

Track of the Tri-state tornado

Nine schools across three states were destroyed in which 69 students were killed. More schools were destroyed and more students killed (as well as the single school record of 33 deaths in De Soto, Illinois) than in any other tornado in U.S. history.^[3] Deaths occurred at many rural schools. Counting those returning home from schools and those that died in schools, the toll was 72 students.^[14]

The very swift moving tornado at times exhibited an unusual appearance due partially to its size and the probable low cloud base of its parent thunderstorm. The tornado was frequently described by witnesses as an amorphous rolling fog or boiling clouds on the ground, and fooled normally weather-wise farm owners (in addition to people in general) who did not sense the danger until the storm was upon them. The condensation funnel was also reportedly sometimes wrapped in copious dust and debris, making it obscured and less recognizable. The parent supercell apparently transitioned to a high-precipitation (HP) variety by the time it was striking West Frankfort, meaning that the tornado wasn't readily visible, as it was often shrouded in heavy rain and hail. The rural death toll of 65 in Hamilton and White counties in southeastern Illinois is unprecedented. 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 U.S.^[14]

The tornado was often accompanied by extreme downburst winds throughout the entirety of its course; the tornado and accompanying downburst increased the width of damage from an average of 0.75 mi (1.21 km) (though at times over 1 mi (1.6 km) wide) to an area 3 mi (4.8 km) wide at times.^[3]

In addition to the dead and injured, thousands were left without shelter or food. Fires erupted, exacerbating the damage. Looting and theft, notably of the property of the dead, was reported. Recovery was generally slow, with the event leaving a lasting blow to the region.

See also

Wikimedia Commons has media related to Tri-State Tornado.

• List of North American tornadoes and tornado outbreaks
• List of tornado-related deaths at schools
• List of F5 and EF5 tornadoes

References

• Flora, Snowden D. (1953). Tornadoes of the United States. Norman, OK: University of Oklahoma Press. ISBN 978-0806102627. 

External links

• 1925 Tri-State Tornado (NWS Paducah, KY)
• The Weather Channel's Storm of the Century list – #7 The Tri-State Tornado
• The Great Tri-State Tornado (RootsWeb Genealogy)
• The 1925 Tornado (Carolyar.com Genealogy)
• aerial film of damage path

Books

• Felknor, Peter S. (1992). The Tri-State Tornado: The Story of America's Greatest Tornado Disaster. Ames, IA: Iowa State University Press. ISBN 0-8138-0623-2. 
• Akin, Wallace E. (2002). The Forgotten Storm: The Great Tri-state Tornado of 1925. Guilford, CT: Lyons Press. ISBN 1-58574-607-X.