95 Fun Facts About Tornado

Which scale has the United States used since 2007 to rate tornado intensity by damage?

The Enhanced Fujita (EF) Scale has rated U.S. tornadoes since February 1, 2007, using damage indicators to estimate wind speeds; it replaced the original 1971 scale.

US tornado damage ratings start at 0 and top out at what number?

The Enhanced Fujita scale runs from EF0 to EF5, six categories in all; ratings are assigned from damage indicators rather than from direct wind measurement.

Which U.S. state experiences the highest average number of tornadoes per year?

Texas averages about 155 tornadoes per year, more than any other U.S. state, largely due to its enormous size and geography.

What is the rotating column of air within a supercell thunderstorm called?

A mesocyclone is a storm-scale region of rotation, typically 2 to 6 miles in diameter, found within supercell thunderstorms. It is a key precursor to tornado formation.

Which 1925 tornado holds the record for the longest continuous path at 219 miles?

The Tri-State Tornado of March 18, 1925, traveled 219 miles across Missouri, Illinois, and Indiana over about 3.5 hours, making it the longest-tracked tornado in recorded history.

Which National Weather Service alert means a tornado has been sighted or detected and people should take cover?

A watch only means conditions are favourable and can span several states; warnings come from local forecast offices and cover an area about the size of a city or small county.

What is the safest place to shelter during a tornado in a house without a basement?

A small interior room on the lowest floor, such as a bathroom or closet, puts the most walls between you and debris; windows, upper floors and garages are the most dangerous spots.

Which country experiences more tornadoes per year than any other?

Canada is a distant second, and Bangladesh suffers the most tornado deaths of any country, around 179 a year.

What type of cloud typically produces tornadoes?

Tornadoes form from cumulonimbus clouds, which are tall, dense thunderstorm clouds that can extend from near the surface to over 40,000 feet. Supercell cumulonimbus clouds are the most prolific tornado producers.

What is a tornado that forms over water called?

A waterspout is a tornado that forms over water or moves from land to water. Fair-weather waterspouts are generally weak, while tornadic waterspouts associated with severe thunderstorms can be much more powerful.

What informal name is given to the corridor of the central United States most prone to tornadoes?

Tornado Alley is the informal name for the area of the central U.S. stretching from Texas northward through Oklahoma, Kansas, Nebraska, and the Dakotas, where tornadoes are most frequent.

What atmospheric condition is most critical for tornado formation?

Wind shear, changes in wind speed and direction with altitude, is essential for tornado formation. It creates the horizontal rotation that can be tilted into a vertical axis by a thunderstorm updraft.

What part of a supercell thunderstorm is a tornado most likely to descend from?

The wall cloud is a localized, persistent lowering of the cloud base that forms beneath the mesocyclone. When rotation tightens sufficiently, a funnel cloud may descend from the wall cloud and become a tornado.

Which 1989 tornado in Bangladesh holds the record as the deadliest single tornado in world history?

The Daulatpur-Saturia tornado struck on April 26, 1989, killing approximately 1,300 people and leaving 80,000 homeless, making it the deadliest single tornado in recorded history.

Approximately how many tornadoes occur in the United States in an average year?

The United States averages approximately 1,200 tornadoes per year, though this number can vary significantly from year to year.

What do storm chasers call the rain-wrapped area of a supercell where a hidden tornado may lurk?

The 'bear' is the tornado under the rotating wall cloud and the 'cage' is the blinding precipitation, sometimes with huge hail, surrounding it.

What colour do tornadoes often turn after crossing Oklahoma's clay-rich soil?

Tornadoes take on the color of the debris and soil they pick up. In areas with red clay soil, such as parts of Oklahoma, tornadoes can appear reddish-brown or rust-colored.

What is the term for a weak, short-lived whirlwind that forms along a thunderstorm gust front?

A gustnado is a small, transient whirlwind that forms along a thunderstorm gust front. Unlike true tornadoes, gustnadoes do not connect to the cloud base and are typically very short-lived.

What is the minimum estimated wind speed for a tornado to receive an EF5 rating?

An EF5 tornado has estimated wind speeds exceeding 200 mph (322 km/h), capable of causing total destruction of well-built structures, sweeping away foundations, and debarking trees.

Which U.S. government agency is responsible for issuing tornado watches?

The Storm Prediction Center (SPC), a division of NOAA's National Weather Service based in Norman, Oklahoma, is responsible for issuing tornado and severe thunderstorm watches across the United States.

In what direction do most tornadoes in the Northern Hemisphere rotate?

Most Northern Hemisphere tornadoes rotate counterclockwise, inheriting the cyclonic spin of the parent supercell's mesocyclone; clockwise (anticyclonic) tornadoes are rare exceptions, often spawned by left-moving storms.

What month typically sees the most tornadoes in the United States?

May historically has the highest average number of tornadoes in the United States, as warm, moist air from the Gulf of Mexico clashes most dramatically with cooler air masses from Canada during this month.

What percentage of all tornadoes are classified as violent (EF4 or EF5)?

Only about 1% of all tornadoes reach violent intensity (EF4 or EF5). However, these rare tornadoes account for a disproportionate share of tornado fatalities and catastrophic damage.

What is a landspout?

Landspouts are usually weaker than supercell tornadoes and get their name from looking like a Florida Keys waterspout over land.

Most tornadoes are on the ground for roughly how long?

Most tornadoes last less than 10 minutes, with the average closer to a few minutes; only rare long-track tornadoes stay on the ground for an hour or more.

What Japanese-American meteorologist developed the original tornado intensity scale in 1971?

Dr. Tetsuya Theodore Fujita, often called 'Mr. Tornado,' developed the Fujita Scale in 1971 while working at the University of Chicago. His pioneering work in analyzing tornado damage patterns revolutionized tornado science.

What is a rotating cone-shaped cloud from a thunderstorm's base that has NOT reached the ground called?

A funnel cloud is a rotating, cone-shaped column of air extending from the base of a cloud. It only becomes classified as a tornado once it makes contact with the ground surface.

Which supercell feature wraps around the mesocyclone and helps tighten low-level rotation into a tornado?

The rear flank downdraft (RFD) descends at the back of a supercell and wraps around the mesocyclone. It is believed to play a critical role in tornado formation by tightening existing rotation near the surface.

Which US city was struck by devastating tornadoes in 1999, 2003 and 2013?

Moore, Oklahoma, a suburb of Oklahoma City, has been struck by multiple significant tornadoes, including an F5 in 1999, an F4 in 2003, and an EF5 in 2013, making it one of the most tornado-impacted cities in the U.S.

Which technology lets forecasters spot rotation inside a thunderstorm before a funnel appears?

Doppler radar can detect rotation within thunderstorms by measuring the velocity of precipitation particles moving toward and away from the radar. This allows meteorologists to identify mesocyclones and issue tornado warnings before a tornado is visually confirmed.

Which dedicated radio service broadcasts National Weather Service alerts continuously from its own transmitters?

NOAA Weather Radio All Hazards carries National Weather Service broadcasts around the clock from more than 1,000 transmitters; receivers with SAME alerting sound an alarm when a tornado warning is issued.

Which country records the most tornadoes per unit of land area?

The Netherlands records the most tornadoes per unit area, about 20 a year over a small territory, mostly weak and brief; the United Kingdom is second by density with around 33 annually.

What is a tornado outbreak?

Typically at least six to ten tornadoes are needed to qualify; the April 2011 Super Outbreak produced more than 360 in four days.

What is the typical width of most tornadoes?

Most tornadoes are about 250 feet (80 m) across, though weak or dying funnels can narrow to a few feet and the very largest exceed a mile in width.

How many people were killed in the 2011 Super Outbreak of tornadoes?

The April 25–28, 2011 Super Outbreak killed about 320 people (324 tornado-related deaths), 316 of them on April 27 alone, from more than 360 confirmed tornadoes including four EF5s.

What truck-mounted radar system lets researchers measure tornado wind speeds up close?

The fleet grew out of the University of Oklahoma's meteorology school and is led by atmospheric scientists Joshua Wurman and Karen Kosiba.

Which tornado 'safety' idea from a viral 1991 video was debunked after people relying on it died?

Sheltering under highway overpasses caught on after a 1991 Kansas Turnpike news video, but three people died doing so in the 3 May 1999 Oklahoma outbreak; the span funnels and accelerates wind and debris.

What was the widest tornado ever recorded in the United States?

The 31 May 2013 El Reno, Oklahoma tornado reached a record width of 2.6 miles (4.2 km), the widest ever measured, and killed several experienced storm chasers.

What is usually behind the green tint the sky sometimes takes on during a severe thunderstorm?

Despite the folklore, there is no known link between green skies and tornadoes specifically; the colour comes with severe, hail-heavy storms in general.

What term describes a thin, twisting funnel most often seen as a twister dies out?

A rope tornado has a thin, rope-like appearance. Tornadoes often take on this shape during their dissipating stage as the funnel narrows and becomes tilted, though some tornadoes maintain a rope-like shape throughout their life.

What is the nickname for a twister that looks wider than the distance from the cloud base to the ground?

A wedge tornado appears wider than the distance from the ground to the cloud base, giving it a wedge or pyramid shape. Wedge tornadoes are often associated with violent (EF4-EF5) intensity and can be over a mile wide.

NOAA's Severe Storms Laboratory puts a typical tornado's forward speed at roughly what?

The National Severe Storms Laboratory says a typical tornado travels at around 10-20 mph, though forward motion ranges from nearly stationary to highway speeds; the rotational winds inside the funnel are far faster.

What is the southeastern US region known as a second hotspot for violent tornadoes called?

Dixie Alley covers parts of Mississippi, Alabama, Tennessee and Georgia, where tornadoes are often fast-moving, nocturnal and hidden by rain, which makes them unusually deadly.

What is a multiple-vortex tornado?

Sub-vortices can add over 100 mph to the wind and explain why narrow arcs of extreme destruction sit right beside light damage in a tornado's path.

In which year were the first public tornado warnings issued in the United States?

Watches and convective outlooks followed two years later, and hook echoes on radar were confirmed as a tornado signature in 1953.

Which is the top tier of the Storm Prediction Center's five severe-weather risk categories?

The Storm Prediction Center's categorical outlook runs Marginal, Slight, Enhanced, Moderate and High; a High risk is reserved for days when a major tornado outbreak is expected.

What is a FEMA safe room?

A FEMA safe room is a hardened structure built to withstand extreme winds, inside a home or standalone; near-absolute protection means a very high probability of surviving uninjured.

What is the underground shelter dug beside many Plains farmhouses to escape tornadoes called?

A storm cellar, also called a cyclone cellar, is an underground room with a heavy sloped door, traditionally dug a few steps from the house because Oklahoma's clay soils make basements rare.

A tornado can sit almost still or race along at more than what ground speed?

The National Severe Storms Laboratory says tornado forward motion ranges from almost stationary to more than 60 mph, and admits there are no detailed statistics on forward speed.

What is a long-lived, widespread straight-line windstorm often mistaken for tornado damage called?

A derecho is a fast-moving band of thunderstorms producing straight-line winds over hundreds of miles; the August 2020 Midwest derecho hit Iowa with gusts over 100 mph.

How many damage indicators does the Enhanced Fujita scale use to estimate tornado winds?

The Enhanced Fujita scale uses 28 damage indicators, from small barns to high-rise buildings, each with degrees of damage tied to wind estimates; surveyors rate the worst credible damage found.

What is the primary danger associated with tornadoes besides high winds?

Flying debris causes most tornado injuries and deaths: winds that strong can loft cars and turn broken glass and lumber into lethal missiles.

Which radar signature, formed as precipitation wraps a supercell's rotating updraft, warns of a tornado?

A hook echo is the curl of precipitation wrapped around the back side of a supercell's rotating updraft on radar; a 1953 Illinois radar image first tied the shape to a tornado.

Which radar upgrade lets forecasters detect lofted debris as a 'tornado debris signature'?

Dual-polarization radar, rolled out across the NEXRAD network by 2013, sends horizontal and vertical pulses; lofted debris of mixed shapes yields a low correlation coefficient, the tornado debris signature that confirms a tornado on the ground.

What does an approaching tornado most commonly sound like?

Survivors most often compare an approaching tornado to a continuous rumble like a freight train; some describe a waterfall-like whoosh, and because many are audible only up close, sound is no reliable alarm.

In which type of dwelling do a disproportionate share of US tornado deaths occur?

Mobile homes account for roughly 40–50 percent of US tornado deaths despite housing well under 10 percent of the population; the NWS advises leaving one for sturdier shelter when a tornado threatens.

Which Texas city's May 1953 tornado killed 114 people?

The Waco tornado of 11 May 1953 killed 114 people and flattened the R.T. Dennis furniture building downtown; it was one of three catastrophic tornadoes that spring that pushed the US toward a national warning network.

What do the letters PDS mean on the most urgent tornado watches?

A PDS, or Particularly Dangerous Situation, tag is added to a tornado watch when forecasters expect multiple strong, long-track tornadoes; only a handful are issued in a typical year.

How long does a typical supercell thunderstorm last?

A typical supercell lasts 2-4 hours, far longer than an ordinary thunderstorm cell's 30-60 minutes, because its rotating updraft stays separate from its downdrafts; some dominate the weather 20 miles around.

The word 'tornado' derives from which Spanish word meaning 'thunderstorm'?

'Tornado' comes from Spanish tronada, 'thunderstorm' (from tronar, 'to thunder'); English speakers swapped the r and o, probably influenced by Spanish tornar, 'to turn'.

What do Doppler radar and rare eyewitness accounts suggest lies at the centre of most tornadoes?

Mobile Doppler radar and a few eyewitness accounts point to a clear, calm core of very low pressure inside most tornadoes, much like a hurricane's eye; those who looked in said lightning lit the interior.

How large a pressure drop did a probe record inside a violent tornado near Manchester, South Dakota, in 2003?

Pressure fell to 850 mbar in the core, producing a V-shaped trace as the vortex passed.

Which country's roughly 62 reported tornadoes a year rank second after the United States?

NOAA puts Canada's true average nearer 100; the Netherlands has the most per unit area.

Roughly how many people do tornadoes kill per year in Bangladesh, the world's highest toll?

Tornadoes kill about 179 people a year in Bangladesh, more than in any other country, because of dense population, flimsy housing and little warning or shelter.

Which UK organisation has run a network of storm spotters since 1974?

TORRO, the Tornado and Storm Research Organisation, has run a volunteer network of UK storm spotters since its founding in 1974 and maintains Britain's tornado database.

What did the research device nicknamed TOTO stand for?

The TOtable Tornado Observatory joined the VORTEX projects and Doppler on Wheels among efforts to probe tornadoes up close.

Who directed the 1996 storm-chasing blockbuster Twister?

Steven Spielberg was originally attached to direct before de Bont took over; the script was co-written by Michael Crichton.

In Twister, what is the name of the sensor-filled device the chasers try to deploy?

The fictional device was a nod to the real TOTO probe. A rival chaser in the film steals the idea for his own version, called Dot3.

Who directed the 2024 standalone sequel Twisters?

Chung was best known for the quiet family drama Minari before taking on the disaster sequel, which starred Daisy Edgar-Jones and Glen Powell.

Which Missouri city did an EF5 tornado strike on 22 May 2011, killing 158 people?

The Joplin, Missouri EF5 of 22 May 2011 killed 158 people, destroyed St. John's Regional Medical Center and caused about $2.8 billion in damage.

Which storm chaser and engineer died with his son in the 2013 El Reno tornado?

Samaras founded the TWISTEX research team and had received 18 National Geographic grants; he, his son Paul and partner Carl Young were caught in their vehicle.

Which Kansas town was hit by the first tornado ever rated EF5, in May 2007?

Greensburg lost about 95% of its buildings and rebuilt as one of America's greenest communities, with wind power and LEED buildings; the EF scale had only replaced the Fujita scale that February.

Which Ohio city suffered the deadliest single tornado of the 1974 Super Outbreak?

Xenia's F5 on 3 April 1974 killed 32 people and levelled much of the town; the outbreak spawned 148 tornadoes in about 18 hours across 13 states.

Codell, Kansas was hit by a tornado on the same date three years running; which date?

Codell, Kansas was struck on May 20 in 1916, 1917 and 1918, a coincidence that made the tiny town a fixture of tornado lore; the 1918 storm was the most destructive of the three.

A 2014 Nebraska tornado set the record forward speed for a violent tornado. How fast?

The Pilger tornado family is also famous for twin EF4 tornadoes that tore across the landscape side by side.

Which is the only continent where tornadoes have never been recorded?

Antarctica is the exception; South America even has its own 'tornado corridor' over the Pampas, where Patagonian air collides with warm, moist air from Brazil.

A rare 1953 tornado killed 94 people in which New England city?

The Worcester, Massachusetts tornado of 9 June 1953 killed 94 people along a 48-mile path, the deadliest tornado ever recorded in New England.

Until 1938, the US Weather Bureau banned which word from its weather products?

The Weather Bureau barred the word 'tornado' from its forecasts from 1887 until 1938, fearing public panic; even afterwards, public tornado forecasts did not begin until 1952.

The first official US tornado forecast, in March 1948, came from officers of which service?

Capt. Robert Miller and Major Ernest Fawbush made the call at Tinker Air Force Base, five days after a tornado had already hit the base.

Sean Casey's armored Tornado Intercept Vehicles film twisters with what kind of camera?

The TIVs carry an IMAX camera to film from inside or very near a tornado; they featured on Discovery's Storm Chasers, and TIV 2 made its strongest intercept in Kansas in May 2013.

Storm chaser Reed Timmer's first Dominator vehicle was modified from which SUV?

Dominator 1 was built from a 2008 Chevrolet Tahoe fitted with armour plating, bullet-resistant polycarbonate windows and hydraulic skirts to keep wind from getting underneath; Timmer debuted it on Discovery's Storm Chasers.

Which scientist founded the Doppler on Wheels mobile radar program in 1995?

Joshua Wurman built the first Doppler on Wheels at the University of Oklahoma in 1995 with NCAR support and later ran the fleet from the Center for Severe Weather Research in Boulder, Colorado.

The second-deadliest US tornado struck which Mississippi river town in 1840?

The Great Natchez Tornado of 7 May 1840 killed at least 317 people, many of them aboard flatboats on the Mississippi, where the storm wrecked most of the boats tied up at the landing.

The 1987 tornado remembered locally as 'Black Friday' struck which Canadian city?

The Edmonton tornado of Friday, 31 July 1987 killed 27 people, ripping through the city's eastern industrial districts and the Evergreen trailer park; Albertans dubbed it Black Friday.

Canada's only F5 tornado hit the town of Elie in 2007 in which province?

Elie, Manitoba, west of Winnipeg, was hit on 22 June 2007 by Canada's only F5 tornado, which lifted a well-built anchored house whole and shredded it in mid-air, yet caused no deaths.

Which English city's southern suburbs were torn up by a tornado on 28 July 2005?

The Birmingham tornado of 28 July 2005 tore through Sparkbrook, Balsall Heath and Moseley on a Thursday afternoon, injuring 19 people and causing about £40 million of damage.

A deadly 1984 tornado outbreak struck the Ivanovo region north of which capital city?

The 9 June 1984 outbreak hit the Ivanovo region about 250 km north-east of Moscow; its main tornado, rated F4, tossed 50-tonne tanks up to 200 metres and killed dozens by official count, possibly hundreds.

An old myth held that which corner of a building was the safest spot in a tornado?

The myth held that the southwest corner was safest because tornadoes usually approach from the southwest and would throw debris to the northeast; damage surveys in the 1960s and 70s showed it was wrong.

What debunked tornado myth claims you can protect a house by equalizing air pressure?

Opening the windows does nothing: a tornado's pressure drop is far too small to burst a house, and windows shatter from airborne wreckage long before pressure matters; wasting time on them is dangerous.

Who devised the T-scale of tornado intensity, which runs from T0 to T10?

Terence Meaden, a British physicist and meteorologist, introduced the T-scale in the mid-1970s as an extension of the Beaufort wind scale, with T0 beginning where Beaufort force 8 leaves off.

In which year was the term 'Tornado Alley' first used, as the title of a research project?

'Tornado Alley' was first used in 1952 as the title of a research project by two military forecasters studying severe weather from Texas to South Dakota; the term has no official boundaries.

The tornado in 1939's The Wizard of Oz was made from 35 feet of which material?

Effects chief Arnold Gillespie built the twister from a 35-foot muslin stocking after a rubber cone proved too stiff; the muslin funnel hung from a gantry and was dusted with fuller's earth.

What was the Storm Prediction Center called before October 1995?

The National Severe Storms Forecast Center, based in Kansas City, became the Storm Prediction Center in October 1995 and moved to Norman, Oklahoma in 1997, where it shares the National Weather Center with NSSL.

Which Chicago-area town was hit in 1990 by the only official August F5 in the US?

The Plainfield tornado of 28 August 1990 killed 29 people and is the only F5 ever recorded in the US in August; no tornado warning had been issued when it struck.

The Enhanced Fujita scale was developed in the early 2000s at which university?

Texas Tech's Wind Science and Engineering Research Center in Lubbock led the project from 2000 to 2004, with dozens of meteorologists and civil engineers refining damage indicators into the Enhanced Fujita scale.