Tornado records
This article lists various tornado records. The most "extreme" tornado in recorded history was the Tri-State Tornado, which spread through parts of Missouri, Illinois, and Indiana on March 18, 1925. It is considered an F5 on the Fujita Scale, even though tornadoes were not ranked on any scale at the time. It holds records for longest path length at, longest duration at about 3½ hours, and fastest forward speed for a significant tornado at anywhere on Earth. In addition, it is the deadliest single tornado in United States history with 695 fatalities. It was also the third-costliest tornado in history at the time, but has been surpassed by several others non-normalized. When costs are normalized for wealth and inflation, it still ranks third today.
The deadliest tornado in world history was the Daulatpur–Saturia tornado in Bangladesh on April 26, 1989, which killed approximately 1,300 people. In the history of Bangladesh at least 19 tornadoes killed more than 100 people each, almost half of the total for the rest of the world.
For 37 years, the most extensive tornado outbreak on record, in almost every category, was the 1974 Super Outbreak, which affected a large area of the central United States and extreme southern Ontario in Canada on April 3 and April 4, 1974. Not only did this outbreak feature 148 tornadoes in only 18 hours, but an unprecedented number of them were violent; 7 were of F5 intensity and 23 were F4. During the peak of this outbreak there were 16 tornadoes on the ground at the same time. More than 300 people, possibly as many as 330, were killed by tornadoes during this outbreak. However, this record was later broken during the 2011 Super Outbreak, which resulted in 360 tornadoes and 324 tornadic fatalities. However, the most tornadoes spawned in the shortest amount of time is 104 over 5 hours and 26 minutes, during the 1981 United Kingdom tornado outbreak on 23 November 1981.
Tornado outbreaks
Most tornadoes in single 24-hour period
The 2011 Super Outbreak was the largest tornado outbreak spawned by a single weather system in recorded history; it produced 360 tornadoes from April 25–28, with 216 of those in a single 24-hour period on April 27 from midnight to midnight CDT, fifteen of which were violent EF4–EF5 tornadoes. 348 deaths occurred in that outbreak, of which 324 were tornado related. The outbreak largely contributed to the record for most tornadoes in the month of April with 771 tornadoes, almost triple the prior record. The overall record for a single month was 542 in May 2003, which was also broken.The infamous 1974 Super Outbreak of April 3–4, 1974, which spawned 148 confirmed tornadoes across eastern North America, held the record for the most prolific tornado outbreak for many years, both in terms of overall number of tornadoes and in violent, long-track tornadoes. More significant tornadoes occurred within 24 hours than any other day on tornado record. Due to a secular trend in tornado reporting, the 2011 and 1974 tornado counts are not directly comparable.
Most violent tornadoes (F4/EF4 and F5/EF5) in an outbreak
Longest continuous outbreak and largest autumnal outbreak
Most tornado outbreaks in North America occur in the spring, but there is a secondary peak of tornado activity in the fall which is less consistent but can include exceptionally large and/or intense outbreaks. In 1992, an estimated 95 tornadoes broke out in a record 41 hours of continuous tornado activity from November 21 to 23. This is also among the largest-known outbreaks in areal expanse. Many other very large outbreaks have occurred in autumn, especially in October and November.Greatest number of tornadoes spawned from a hurricane
The greatest number of tornadoes spawned from a hurricane is 118 from Hurricane Ivan in 2004. Caution is advised comparing the raw number of counted tornadoes from recent decades to decades prior to the 1990s since more tornadoes that occur are now recorded than in the past.Tornado casualties and damage
Deadliest single tornado in world history
On April 26, 1989 in Bangladesh a large tornado took at least 1,300 lives.Deadliest single tornado in US history
The Tri-State Tornado of March 18, 1925 killed 695 people in Missouri, Illinois, and Indiana. The outbreak it occurred with was also the deadliest known tornado outbreak, with a combined death toll of 747 across the Mississippi River Valley.Most damaging tornado
Similar to fatalities, damage of a tornado are a coincidence of what character of tornado interacts with certain characteristics of built up areas. That is, destructive tornadoes are in a sense "accidents" of a large tornado striking a large population. In addition to population and changes thereof, comparing damage historically is subject to changes in wealth and inflation. The 1896 St. Louis–East St. Louis tornado on May 27, incurred the most damages adjusted for wealth and inflation, at an estimated $2.9 billion. In raw numbers, the Joplin tornado of May 22, 2011 is considered the costliest tornado in recent history, with damage totals near $2.8 billion. Until 2011, the Bridge Creek-Moore tornado of May 3, 1999 was the most damaging.Largest and most powerful tornadoes
Highest winds observed in a tornado
During the F5 1999 Bridge Creek–Moore tornado on May 3, 1999 in the southern Oklahoma City metro area, a Doppler on Wheels situated near the tornado measured winds of momentarily in a small area inside the funnel approximately above ground level. These are also the highest wind speeds observed on Earth.On May 31, 2013, a tornado hit rural areas near El Reno, Oklahoma. The tornado was originally rated as an EF3 based on damage; however, after mobile radar data analysis was conducted, it was concluded to have been an EF5 due to a measured wind speed of greater than, second only to the Bridge Creek–Moore tornado. Revised RaXPol analysis found winds of well above ground level and ≥ below with some subvortices moving at. These winds may possibly be as high or higher than the winds recorded on May 3, 1999. Despite the recorded windspeed, the El Reno tornado was later downgraded back to EF3 due to the fact that no EF5 damage was found, likely due to the lack of sufficient damage indicators in the largely rural area west of Oklahoma City.
Winds were measured at using portable Doppler radar in the Red Rock, Oklahoma tornado during the April 26, 1991 tornado outbreak in north-central Oklahoma. Though these winds are possibly indicative of an F5 strength tornado, this particular tornado's path never encountered any significant structures and caused minimal damage. Thus it was rated an F4.
Longest damage path and duration
The longest-known track for a single tornado is the Tri-State Tornado with a path length of. For years there was debate whether the originally recognized path length of over 3.5 hours was from one tornado or a series. Some very long track tornadoes were later determined to be successive tornadoes spawned by the same supercell thunderstorm, which are known as a tornado family. The Tri-State Tornado, however, appeared to have no gaps in the damage. A six-year reanalysis study by a team of severe convective storm meteorologists found insufficient evidence to make firm conclusions but does conclude that it is likely that the beginning and ending of the path was resultant of separate tornadoes comprising a tornado family. It also found that the tornado began to the west and ended farther east than previously known, bringing the total path to. The segment from central Madison County, Missouri to Pike County, Indiana is likely one continuous tornado and the segment from central Bollinger County, Missouri to western Pike County, Indiana is very likely a single continuous tornado. Another significant tornado was found about east-northeast of the end of aforementioned segment of the Tri-State Tornado Family and is likely another member of the family. Its path length of over about 20 minutes makes the known tornado family path length total to over about 5½ hours. Grazulis in 2001 wrote that the first of the track is probably the result of two or more tornadoes and that a path length of was seemingly continuous.Longest path and duration tornado family
What at one time was thought to be the record holder for the longest tornado path is now thought to be the longest tornado family, with a track of at least on May 26, 1917 from the Missouri border across Illinois into Indiana. It caused severe damage and mass casualties in Charleston and Mattoon, Illinois.What was probably the longest track supercell thunderstorm tracked across 6 states in 17.5 hours on March 12, 2006 as part of the March 2006 tornado outbreak sequence. It began in Noble County, Oklahoma and ended in Jackson County, Michigan, producing many tornadoes in Missouri and Illinois.
Largest path width
Officially, the widest tornado on record is the El Reno, Oklahoma tornado of May 31, 2013 with a width of at its peak. This is the width found by the National Weather Service based on preliminary data from University of Oklahoma RaXPol mobile radar that also sampled winds of which was used to upgrade the tornado to EF5. However, it was revealed that these winds did not impact any structures, and as a result the tornado was downgraded to EF3 based on damage.The F4 Hallam, Nebraska tornado during the outbreak of May 22, 2004 was the previous official record holder for the widest tornado, surveyed at wide. A similar size tornado struck Edmonson, Texas on May 31, 1968, when a damage path width between was recorded from an F3 tornado.
Highest forward speed
The highest forward speed of a tornado on record was 73 miles per hour from the 1925 Tri-State Tornado. Other weak tornadoes have approached or exceeded this speed, but this is the fastest forward movement observed in a major tornado.Greatest pressure drop
A pressure deficit of was observed when a violent tornado near Manchester, South Dakota on June 24, 2003 passed directly over an in-situ probe that storm chasing researcher Tim Samaras deployed. In less than a minute, the pressure dropped to, which are the greatest pressure decline and the lowest pressure ever recorded at the Earth's surface when adjusted to sea level.On April 21, 2007, a pressure deficit was reported when a tornado struck a storm chasing vehicle in Tulia, Texas. The tornado caused EF2 damage as it passed through Tulia. The reported pressure drop far exceeds that which would be expected based on theoretical calculations.
There is a questionable and unofficial citizen's barometer measurement of a drop around Minneapolis in 1904.
Early tornadoes
Earliest-known tornado in Europe
- The earliest recorded tornado in Europe struck Freising in 788.
- The earliest-known Irish tornado appeared on April 30, 1054 in Rostella, near Kilbeggan. The earliest-known British tornado hit central London on October 23, 1091 and was especially destructive.
Earliest-known tornado in the Americas
- An apparent tornado is recorded to have struck Tlatelolco, on August 21, 1521, two days before the Aztec capital's fall to Cortés. Many other tornadoes are documented historically within the Basin of Mexico.
First confirmed tornado and first tornado fatality in present-day United States
- August 1671 – Rehoboth, Massachusetts
- July 8, 1680 – Cambridge, Massachusetts – 1 dead
First published scientific studies of a tornado
For intensive studies of tornadoes, these are the earliest known publications:
- 1839–41: A detailed survey of damage path of significant tornado that struck New Brunswick, New Jersey on 19 June 1835, which was the deadliest tornado in New Jersey history. The path was surveyed by many scientists on account of its location between New York City and Philadelphia, including early tornado theorists James Pollard Espy and William Charles Redfield. Scientists disagreed whether there was whirling, convergent, or rotational motion. A conclusion that remains accurate today is that the most intense damage tends to be on right side of a tornado.
- 1840: The earliest known intensive study of a tornadic event published in Europe, by French scientist Athanase Peltier.
- 1865: The first in India and earliest known scientific survey of a tornado that analyzed structure and dynamics was published in 1865 by Indian scientist Chunder Sikur Chatterjee. The path damage survey of a tornado that occurred at Pundooah, Hugli district, West Bengal, India, was documented on maps and revealed multiple vortices, the tornadocyclone, and direction of rotation, predating work by John Park Finley, Alfred Wegener, Johannes Letzmann, and Ted Fujita.
Exceptional tornado droughts