Tornado records

A map of the tornado paths in the Super Outbreak

This article lists various tornado records. The most extreme tornado in recorded history was the Tri-State Tornado, which roared through parts of Missouri, Illinois, and Indiana on March 18, 1925. It was likely an F5, though tornadoes were not ranked on any scale in that era. It holds records for longest path length (219 miles, 352 km), longest duration (about 3.5 hours), and fastest forward speed for a significant tornado (73 mph, 117 km/h) anywhere on earth. In addition it is the deadliest single tornado in United States history (695 dead). It was also the second 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 Daultipur-Salturia Tornado in Bangladesh on April 26, 1989, which killed approximately 1,300 people. Bangladesh has had at least 19 tornadoes in its history kill more than 100 people, almost half of the total for the rest of the world.

The most extensive tornado outbreak on record, in almost every category, was the 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 an incredible 148 tornadoes in only 18 hours, but an unprecedented number of them were violent; 6 were of F5 intensity and 24 were F4. This outbreak had a staggering 16 tornadoes on the ground at the same time at the peak of the outbreak. More than 300 people, possibly as many as 330, were killed by tornadoes during this outbreak. However, this record was later broken during the April 25–28, 2011 tornado outbreak, which resulted in 320+ casualties and had 359 tornadoes touch down.

Tornado outbreaks

Most tornadoes in single 24-hour outbreak

The Super Outbreak of April 3–4, 1974 spawned 148 confirmed tornadoes across eastern North America and resulted in the second highest death toll (319) for a tornado outbreak in the United States.^{[citation needed]} Not only did it produce an exceptional number of tornadoes, but it was also an inordinately intense outbreak producing dozens of large, long-track tornadoes, including 6 F5 and 24 F4 tornadoes. More significant tornadoes occurred within 24 hours than any other week in the tornado record.

The April 25–28, 2011 tornado outbreak has broken the Super Outbreak's record. The National Weather Service reports that the outbreak produced approximately 359 tornadoes, with 207 of those in a single 24-hour period. 335 deaths occurred in that same 24-hour time period. The outbreak has also helped smash the record for most tornadoes in the month of April with 771 tornadoes, more than double the prior record (267 in April 1974). The overall record for a single month was 542 in May 2003, which has also been broken.

Largest outbreak in the fall

Most tornado outbreaks occur in the spring, but there is a secondary peak of tornado activity in the fall. In 1992, 95 tornadoes broke out in 41 hours of continuous tornado activity from November 21 to 23. Many other very large outbreaks have occurred in the fall, especially in November and early December.

Longest continuous outbreak

Under most definitions, the November 1992 tornado outbreak is also the longest continuous tornado outbreak, and among the largest in geographic scope, as well.

Most tornadoes spawned from a hurricane

The greatest number of tornadoes spawned from a hurricane is 117 from Hurricane Ivan in 2004

Tornado casualties and damage

For a more comprehensive list, see List of tornadoes causing 100 or more deaths.

Deadliest single tornado in world history

April 26, 1989 - Bangladesh - A massive tornado took 1,418 lives

Deadliest single tornado in US history

The Tri-State Tornado of March 18, 1925 killed 695 people in Missouri (11), Illinois (613), and Indiana (71). 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 (and observations) 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 St. Louis-East St. Louis Tornado of May 27, 1896 incurred the most damages adjusted for wealth and inflation, at an estimated $2.9 billion (1997 USD). In raw numbers, the "Oklahoma City Tornado" of May 3, 1999 is the most damaging.

Largest and most powerful tornadoes

Highest winds observed in a tornado

During the F5 tornado that moved into Oklahoma City on May 3, 1999, a Doppler On Wheels situated near the tornado measured winds of 301 +/- 20 mph (484 +/- 32 km/h) momentarily in a small area inside the funnel approximately 100 m (330 ft) above ground level.

Winds were measured at 257-268 mph (414–431 km/h) using portable doppler radar in the Red Rock Tornado during the Andover, Kansas Tornado Outbreak. 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 track single tornado is the Tri-State Tornado, which traversed ≥219 miles (≥352 km) across southeastern Missouri, southern Illinois, and southwestern Indiana in about 3.5 hours. Though there has been some discussion as to whether this was a single tornado or a tornado family, recent and ongoing detailed reanalysis has found no break in the path and in fact that the tornado began 15 mi (24 km) before previously thought.

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 293 miles (472 km) 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 790 miles (1,271 km) 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.

Widest damage width

The widest tornado (defined as damage path, not condensation/debris cloud or radar measurements) on record is the Wilber - Hallam, Nebraska tornado during the outbreak of May 22, 2004, with a width of 2.5 miles (4 km) at its peak.

The widest tornado as measured by actual radar wind measurements was the Mulhall (1999) tornado in northern Oklahoma which occurred during the 1999 Oklahoma tornado outbreak. The diameter of the maximum winds (over 110 metres per second (250 mph)) was over 1600 m as measured by a DOW radar. Although the tornado passed largely over rural terrain, the width of the wind swath capable of producing damage was as wide as 4 miles (7 km), making the actual wind field of the Mulhall tornado likely twice as wide as that of the Hallam tornado (the wind field of which was not measured), even though the Hallam tornado resulted in a wider damage path.

Highest forward speed

73 mph (117 km/h) from the 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 100 millibars (2.95 inHg) was observed when a violent tornado near Manchester, South Dakota on June 24, 2003 passed directly over an in-situ probe. In less than a minute the pressure dropped to 850 millibars (25.10 inHg), which is the lowest pressure ever recorded at the Earth's surface when adjusted to sea level.

On April 21, 2007, a 194 millibars (5.73 inHg) pressure deficit was reported when a tornado struck a storm chasing vehicle in Tulia, Texas. However, the pressure instrument was inside a vehicle which experienced winds greater than 50 metres per second (110 mph) and therefore this measurement was likely contaminated substantially by dynamic effects. The tornado was relatively weak and caused only EF2 damage as it passed through Tulia.^{[citation needed]} 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 192 millibars (5.67 inHg) drop around Minneapolis, Minnesota in 1904.

Early tornadoes

Earliest known tornado in Europe

• The earliest recorded tornado in Europe struck Rosdalla, near Kilbeggan, Ireland on April 30, 1054. 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 (present day Mexico City), 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 the U.S.

• August 1671 - Rehoboth, Massachusetts
• July 8, 1680 - Cambridge, Massachusetts - 1 dead

Exceptional tornado droughts

Longest span without a tornado rated F5 or EF5

Before the Greensburg EF5 tornado on May 4, 2007, it had been 8 years and one day since the US has had a confirmed F5 or EF5 tornado. The last confirmed F5 or EF5 hit southern Oklahoma City and surrounding communities during the May 3, 1999 event. This is the longest interval without a F5 or EF5 tornado since official records began in 1950.

Exceptional survivors

Longest distance carried by a tornado

Matt Suter of rural Fordland, Missouri, according to Thomas P. Grazulis, holds the record for the longest known distance traveled by anyone picked up by a tornado who lived to tell about it. On March 12, 2006 he was carried 1307 feet (398 m), according to National Weather Service measurements.

Exceptional coincidences

Codell, Kansas

The small town of Codell, Kansas, was hit by a tornado on the same date three consecutive years. A tornado hit on May 20, 1916, 1917, and 1918. The U.S. has about 100,000 thunderstorms a year; less than 1% produce a tornado. The odds of this coincidence occurring again is extremely small.

Tanner, Alabama

A small town in northern Alabama, Tanner, was hit by a F5 tornado on April 3, 1974 during the Super Outbreak and was struck again 45 minutes later by at least a high-end F4 (some sources say F5), demolishing what remained of the town. 37 years later, on April 27, 2011, during what some meteorologists have dubbed Super Outbreak II, Tanner was hit yet again by the EF5 Hackleburg tornado, producing high-end EF4 damage in the southern portion of town.

See also

• Weather records
• List of tropical cyclone extremes
• Tornado myths
• List of F5 and EF5 tornadoes
• List of tornadoes and tornado outbreaks
• List of tornado-related deaths at schools

External links

• More on tornadoes: Records, the Fujita scale, and our observations by Chuck Doswell
• CBC Digital Archives - Deadly Skies: Canada's Most Destructive Tornadoes