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Moisture streams in from the side of the precipitation free base and flanking line into a warm uplift region where the tower of the thundercloud is tipped by the high altitude shear winds; the uplift is influenced by the Coriolis effect and the mass of clouds spins as it gains altitude up to the cap (can be up to the 55,000–70,000 feet above ground for the largest) and 'trailing' anvil. The capped moisture laden air is cooled enough to precipitate as it is rotated toward the cooler region represented by the turbulent air of the mammatus clouds where the warm air is spilling over top of the cooler invading airs. The cap is formed where shear winds (jet stream lower side) block further uplift for a time, until a relative weakness allows a breakthrough of the cap (Overshooting top); Cooler air to the right in the image may or may not form a shelf cloud, but the precipitation zone will occur where the heat engine of the uplift intermingles with the invading colder air. As the cooler but drier air circulates to the warm moisture laden inflow, the cloud base will frequently form a wall and the cloud base often experiences a 'lowering', which in extreme cases are where the tornadoes are born.
Shelf structure forms when a cooler air mass under-flows the warmer moisture laden air.
A supercell. While many ordinary thunderstorms (squall line, single-cell, multi-cell) are similar in appearance, supercells are distinguishable by their large-scale rotation.
Supercells forming near Deshler, Nebraska.

A supercell is a thunderstorm that is characterized by the presence of a mesocyclone: a deep, persistently rotating updraft.1 For this reason, these storms are sometimes referred to as rotating thunderstorms.2 Of the four classifications of thunderstorms (supercell, squall line, multi-cell, and single-cell), supercells are the overall least common and have the potential to be the most severe. Supercells are often isolated from other thunderstorms, and can dominate the local weather up to 32 kilometres (20 mi) away.

Supercells are often put into three classification types: Classic, Low-precipitation (LP) and High-precipitation (HP). LP supercells are usually found in climates that are more arid, such as the high plains of the United States, and HP supercells are most often found in moist climates. Supercells can occur anywhere in the world under the right pre-existing weather conditions, but they are most common in the Great Plains of the United States in an area known as Tornado Alley and in the plains of Argentina, Uruguay and southern Brazil.


Supercells are usually found isolated from other thunderstorms, although they can sometimes be embedded in a squall line. Typically, supercells are found in the warm sector of a low pressure system propagating generally in a north easterly direction in line with the cold front of the low pressure system. Because they can last for hours, they are known as quasi-steady-state storms. Supercells have the capability to deviate from the mean wind. If they track to the right or left of the mean wind (relative to the vertical wind shear), they are said to be "right-movers" or "left-movers," respectively. Supercells can sometimes develop two separate updrafts with opposing rotations, which splits the storm into two supercells: one left-mover and one right-mover.

Supercells can be any size – large or small, low or high topped. They usually produce copious amounts of hail, torrential rainfall, strong winds, and substantial downbursts. Supercells are one of the few types of clouds that typically spawn tornadoes within the mesocyclone, although only 30% or less do so.3


Supercells can occur anywhere in the world under the right weather conditions. The first storm to be identified as the supercell type was the Wokingham storm over England, which was studied by Keith Browning and Frank Ludlam in 1962.4 Browning did the initial work that was followed up by Lemon and Doswell to develop the modern conceptual model of the supercell.5 To the extent that records are available, supercells are most frequent in the Great Plains of the central United States and southern Canada extending into the southeastern U.S. and northern Mexico; east-central Argentina and adjacent regions of Uruguay; Bangladesh and parts of eastern India; South Africa; and eastern Australia.6 Supercells occur occasionally in many other mid-latitude regions, including eastern China and throughout Europe. The areas with highest frequencies of supercells are similar to those with the most occurrences of tornadoes; see tornado climatology and Tornado Alley.

Anatomy of a supercell

The current conceptual model of a supercell was described in Severe Thunderstorm Evolution and Mesocyclone Structure as Related to Tornadogenesis by Leslie R. Lemon and Charles A. Doswell III. (See Lemon technique).

Supercells derive their rotation through tilting of horizontal vorticity (an invisible horizontal vortex) caused by wind shear. Strong updrafts lift the air turning about a horizontal axis and cause this air to turn about a vertical axis. This forms the deep rotating updraft, the mesocyclone.

A cap or capping inversion is usually required to form an updraft of sufficient strength. The cap puts an inverted (warm-above-cold) layer above a normal (cold-above-warm) boundary layer, and by preventing warm surface air from rising, allows one or both of the following:

  • Air below the cap warms and/or becomes more moist
  • Air above the cap cools

This creates a warmer, moister layer below a cooler layer, which is increasingly unstable (because warm air is less dense and tends to rise). When the cap weakens or moves, explosive development follows.

In North America, supercells usually show up on Doppler radar as starting at a point or hook shape on the southwestern side, fanning out to the northeast. The heaviest precipitation is usually on the southwest side, ending abruptly short of the rain-free updraft base or main updraft (not visible to radar). The rear flank downdraft, or RFD, carries precipitation counterclockwise around the north and northwest side of the updraft base, producing a "hook echo" that indicates the presence of a mesocyclone.

Wind shear (red) sets air spinning (green)
The updraft (blue) 'bends' the spinning air upwards
The updraft starts rotating with the spinning column of air

Features of a supercell

Features of a supercell. Northwestward view in the Northern Hemisphere
Diagram of supercell from above. RFD: rear flank downdraft, FFD: front flank downdraft, V: V-notch, U: Main Updraft, I: Updraft/Downdraft Interface, H: hook echo

Overshooting top

This "dome" feature appears above the strongest updraft location on the anvil of the storm. It is a result of a very powerful updraft; enough to break through the upper levels of the troposphere. An observer who is at ground level too close to the storm is unable to see the overshooting top due to the fact that the anvil blocks the sight of this feature.


An anvil forms when the storm's updraft collides with the upper levels of the lowest layer of the atmosphere, or the troposphere, and has nowhere else to go due to the laws of fluid dynamics- specifically pressure, humidity, and density. The anvil is very cold and virtually precipitation free even though virga can be seen falling from the forward sheared anvil. Since there is so little moisture in the anvil, winds can move freely. The clouds take on their anvil shape when the rising air reaches 50,000–70,000 feet (15,200–21,300 m) or more. The anvil's distinguishing feature is that it juts out in front of the storm like a shelf. In some cases, it can even shear backwards, called a backsheared anvil, another sign of a very strong updraft.

Precipitation-free base

This area, typically on the southern side of the storm in North America, is relatively precipitation free. This is located beneath the main updraft, and is the main area of inflow. While no precipitation may be visible to an observer, large hail may be falling from this area. A region of this area is called the Vault. It is more accurately called the main updraft area.

Wall cloud

The wall cloud forms near the downdraft/updraft interface. This "interface" is the area between the precipitation area and the precipitation-free base. Wall clouds form when rain-cooled air from the downdraft is pulled into the updraft. This wet, cold air quickly saturates as it is lifted by the updraft, forming a cloud that seems to "descend" from the precipitation-free base. Wall clouds are common and are not exclusive to supercells: Only a small percentage actually produce a tornado but if a storm does produce a tornado it is usually wall clouds that persist for more than ten minutes, wall clouds that seem to move violently up or down, and violent movements of cloud fragments (scud or fractus) near the wall cloud are indications that a tornado could form.

Mammatus clouds

Mammatus (Mamma, Mammatocumulus) are bulbous or pillow-like cloud formations extending from beneath the anvil of a thunderstorm. These clouds form as cold air in the anvil region of a storm sinks into warmer air beneath it. Mammatus are most apparent when they are lit from one side or below and are therefore at their most impressive near sunset or shortly after sunrise when the sun is low in the sky. Mammatus are not exclusive to supercells and can be associated with developed thunderstorms and cumulonimbus.

Forward Flank Downdraft (FFD)

This is generally the area of heaviest and most widespread precipitation. Between the precipitation-free base and the FFD, a "vaulted" or "cathedral" feature can be observed. In high precipitation supercells an area of heavy precipitation may occur beneath the main updraft area where the vault would alternately be observed with classic supercells.

Rear Flank Downdraft (RFD)

The RFD of a supercell is a very complex and not yet fully understood feature. RFD mainly occur within classic and HP supercells although RFDs have been observed within LP supercells. The RFD of a supercell is believed to play a large part in tornadogenesis by further tightening rotation within the surface mesocyclone. RFDs are caused by mid level steering winds of a supercell colliding with the updraft tower and moving around it in all directions; specifically the flow that is redirected downward is referred to as the RFD. This downward surge of relatively cool mid level air, due to interactions between dew points, humidity, and condensation of the converging of air masses, can reach very high speeds and is known to cause widespread wind damage. The radar signature of an RFD is a hook like structure where sinking air has brought with it precipitation.


A vault is not observed with all supercells. The vault can only be identified visibly due to it visibly appearing to be free of precipitation but usually containing large hail. On Doppler radar, the region of very high precipitation echos with a very sharp gradient perpendicular to the RFD.

Flanking line

A line of smaller cumulonimbi or cumulus that form in the warm rising air pulled in by the main updraft. Due to convergence and lifting along this line, landspouts sometimes occur on the outflow boundary of this region.

Radar features of a supercell

Radar reflectivity map

The "hook echo" is the area of confluence between the main updraft and the rear flank downdraft (RFD). This indicates the position of the mesocyclone, and probably a tornado.

This is a region of low radar reflectivity bounded above by an area of higher radar reflectivity with an untilted updraft. This is evidence of a strong updraft.

  • Inflow notch

A "notch" of weak reflectivity on the inflow side of the cell. This is not a V-Notch.

  • V Notch

A "V" shaped notch on the leading edge of the cell, opening away from the main downdraft. This is an indication of divergent flow around a powerful updraft.

  • Hail spike

This three body scatter spike is a region of weak echoes found radially behind the main reflectivity core at higher elevations when large hail is present.7

Supercell variations

Supercell thunderstorms are sometimes classified by meteorologists and storm spotters into three categories. However, not all supercells fit neatly into any one category, being hybrid storms, and many supercells may fall into different categories during different periods of their lifetimes. The standard definition given above is referred to as the Classic supercell. All types of supercells typically produce severe weather.

Low Precipitation (LP)

Idealized view of an LP supercell

LP supercells contain a small precipitation (rain/hail) core separate from the updraft. This type of supercell may be easily identifiable with "sculpted" cloud striations in the updraft base or even a "corkscrewed" or "barber pole" appearance on the updraft, and sometimes an almost "anorexic" look compared to classic supercells. This is because they often form along dry lines, thus leaving them with little available moisture despite high upper level wind shear. They usually dissipate rapidly rather than turning into classic or HP supercells, although it is still not unusual for them to do the latter, especially if they happen to collide with a much moister air mass along the way. Although these storms usually produce weak tornadoes, they have been known to produce strong ones. These storms usually produce hail less than 1.00 inch (25.4 mm) in diameter8 but can produce large hail even with little or no visible precipitation core, making them hazardous to storm chasers and people and animals caught outside. Due to the lack of a heavy precipitation core, LP supercells can sometimes show weak radar reflectivity without clear evidence of a hook echo, when in fact they are producing a tornado at the time. This is where observations by storm spotter and storm chasers may be of vital importance. Funnel clouds, or more rarely, weak tornadoes will sometimes form midway between the base and the top of the storm, descending from the main Cb (cumulonimbus) cloud. Lightning is rare compared to other supercell types, but it is not unknown and is more likely to occur as intracloud lightning rather than cloud-to-ground lightning. In North America, these storms almost exclusively form in the semi-arid Great Plains during the spring and summer months. Moving east and southeast, they often collide with moist air masses from the Gulf of Mexico, leading to the formation of HP supercells in areas just to the west of Interstate 35 before dissipating further east. LP supercells can occur as far north as Montana, North Dakota and even in the provinces of Alberta and Saskatchewan in Canada. They have also been observed by storm chasers in Australia and Argentina (the Pampas).

LP supercells are quite sought after by storm chasers, because the limited amount of precipitation makes sighting tornadoes at a safe distance much less difficult than with a Classic or HP supercell. During spring and early summer, areas in which LP supercells are readily spotted include southwestern Oklahoma and northwestern Texas, among other parts of the western Great Plains.

High Precipitation (HP)

High precipitation supercell

The HP supercell has a much heavier precipitation core that can wrap all the way around the mesocyclone. These are especially dangerous storms, since the mesocyclone is wrapped with rain and can hide a tornado (if present) from view. These storms also cause flooding due to heavy rain, damaging downbursts and weak tornadoes, although they are also known to produce strong to violent tornadoes. They have a lower potential for damaging hail than Classic and LP supercells, although damaging hail is possible. It has been observed by some spotters that they tend to produce more cloud-to-ground and intracloud lightning than the other types. Also, unlike the LP and Classic types, severe events usually occur at the front (southeast) of the storm. The HP supercell is the most common type of supercell in the United States east of Interstate 35, in the southern parts of the provinces of Ontario and Quebec in Canada, and in the central portions of Argentina and Uruguay.

Mini-supercell or low-topped supercell

Whereas classic, HP, and LP refer to different precipitation regimes and mesoscale frontal structures, another variation was identified in the early 1990s by Jon Davies.9 These smaller storms were initially called mini-supercells10 but are now commonly referred to as low-topped supercells. These are also subdivided into Classic, HP and LP types.


Satellite view of a supercell

Supercells can produce large hail, damaging winds, deadly tornadoes, flooding, dangerous cloud-to-ground lightning, and heavy rain.

Severe events associated with a supercell almost always occur in the area of the updraft/downdraft interface. In the Northern Hemisphere, this is most often the rear flank (southwest side) of the precipitation area in LP and classic supercells, but sometimes the leading edge (southeast side) of HP supercells.

While tornadoes are perhaps the most dramatic of these severe events, all are dangerous. High winds caused by powerful outflow can reach over 148 km/h (92 mph)1112 and downbursts can cause tornado-like damage. Flooding is the leading cause of death associated with severe weather.13

Note that none of these severe events are exclusive to supercells, although these events are highly predictable once a supercell has formed.


The supercell is a global phenomenon, as evidenced by these examples.


Some reports suggest that the deluge on 26 July 2005 in Mumbai, India was caused by a supercell when there was a cloud formation 15 kilometres (9.3 mi) high over the city. On this day 944 mm (37.2 in) of rain fell over the city, of which 700 mm (28 in) fell in just four hours. The rainfall coincided with a high tide, which exacerbated conditions.14


On April 14, 1999, a severe storm later classified as a supercell hit the east coast of New South Wales. It is estimated that the storm dropped 500,000 tonnes (490,000 long tons; 550,000 short tons) worth of hailstones during its course. At the time it was the most costly disaster in Australia's insurance history, causing an approximated A$2.3 billion worth of damage, of which A$1.7 billion was covered by insurance.

On February 27, 2007 a supercell hit Canberra, dumping nearly one metre (39 inches) of ice in Civic. The ice was so heavy that a newly built shopping center's roof collapsed, birds were killed in the hail produced from the supercell, and people were stranded. The following day many homes in Canberra were subjected to flash flooding, caused either by storm water infrastructure's inability to cope or through mud slides from cleared land.15

In 2010, on 6 March, supercell storms hit Melbourne. The storms caused flash flooding in the center of the city and tennis ball-sized (10 cm or 4 in) hailstones hit cars and buildings, causing more than $220 million worth of damage, and sparking 40,000-plus insurance claims. In just 18 minutes, 19 mm (0.75 in) of rain fell, causing havoc as streets were flooded and trains, planes and cars were brought to a standstill.16

That same month, on March 22, 2010 a supercell hit Perth. This storm was one of the worst in the city's history, causing hail stones of 6 centimetres (2.4 in) in size and torrential rain. The city had its average March rainfall in just seven minutes during the storm. Hail stones caused severe property damage, from dented cars to smashed windows.17 The storm itself caused more than 100 million dollars in damage.18

South America

This area called the corridor tornadoes south america, is considered second in the world with more severe weather phenomena after United State. The supercell is common in South America , especially in spring and summer ,in Argentina , Uruguay , Paraguay and brazil , where storms often cause tornadoes of different intensities. The September 16, 1816 one supercell register one of the first tornadoes , which destroyed the town of Rojas ( 240 km west of the city of Buenos Aires). The September 20, 1926 an EF4 tornado struck the city of Encarnación ( Paraguay ) killed over 300 people , the second deadliest tornado in South America. On 21 April 1970, Fray Marcos (Department of Florida), an F4 that killed 11 . It was the strongest in the history of Uruguay . The January 10, 1973 saw the most severe tornado Hall History of South America : The san justo tornado , 105 km north of the city of Santa Fe ( in Argentina ), which was considered EF5 the worst tornado in the history of the southern hemisphere of the planet, with winds that exceeded 400 km/h. The April 13, 1993 , in less than 24 hours in the province of Buenos Aires was given the largest tornado outbreak in the history of South America. There were more than 300 tornadoes recorded, with intensities between F1 and F3. The most affected towns were Henderson ( EF3 ) , Urdampilleta ( EF3 ) and Mar del Plata ( EF2 ) . In December 2000 a series of 12 tornadoes (only registered ) . Affected the Greater Buenos Aires and the province of Buenos Aires , causing serious damage . One of them struck the town of Guernica , and just two weeks later, in January 2001, an EF3 again devastated Guernica , killing 2 people . The December 26, 2003 Tornado F3 happened in Cordoba, with winds exceeding 300 km / h, which hit Córdoba Capital, hit just 6 km from the city center, in the area known as CPC Route 20, especially neighborhoods of San Roque and Villa Fabric, killing 5 people and injuring hundreds. In 2004, the tornado that destroyed the state of São Paulo, was one of the most destructive in the state. Destroyed several industrial buildings, with 400 houses, left 1 dead and 11 wounded. The tornado was rated EF3, but many claim it was a tornado EF4. In November 2009, four tornados category F1 and F2 reached the town of Posadas ( capital of the province of Misiones ), Argentina ), generating serious damage in the city. Three of the tornado affected area of the airport , causing damage in Barrio Belén . On April 4, 2012 , the Gran Buenos Aires was hit by the storm Buenos Aires , with intensities F1 and F2, which left nearly 30 dead in various locations. The February 21, 2014 , in Berazategui ( province of Buenos Aires ) , tornado intensity F1 caused material damage including a car was , with two occupants inside, which was elevated a few feet off the ground and flipped over asphalt , both the driver and his passenger were slightly injured . The tornado caused no fatalities. The severe weather that occurred on Tuesday 8/11 had features rarely seen in such magnitude in Argentina. In many towns of La Pampa, San Luis, Buenos Aires and Cordoba, intense hail stones fell up to 6 cm in diameter. All day Sunday December 8, 2013 was recorded severe storms in the center and the coast . The most affected province was Córdoba , storms and supercells type "Bow Echos " also developed in Santa Fe and San Luis.


In 2009, on the night of Monday May 25, a supercell formed over Belgium. It was described by Belgian meteorologist Frank Deboosere as "one of the worst storms in recent years" and caused much damage in Belgium - mainly in the provinces of East Flanders (around Ghent), Flemish Brabant (around Brussels) and Antwerp. The storm occurred between about 1:00am and 4:00am local time. An incredible 30,000 lightning flashes were recorded in 2 hours - including 10,000 cloud-to-ground strikes. Hailstones up to 6 centimetres (2.4 in) across were observed in some places and wind gusts over 90 km/h (56 mph); in Melle near Ghent a gust of 101 km/h (63 mph) was reported. Trees were uprooted and blown onto several motorways. In Lillo (east of Antwerp) a loaded goods train was blown from the rail tracks.1920

On August 18, 2011, the rock festival Pukkelpop in Kiewit, Hasselt (Belgium) may have been seized by a supercell with mesocyclone around 18:15. Tornado-like winds were reported, trees of over 30 centimetres (12 in) diameter were felled and tents came down. Severe hail scourged the campus. Five people reportedly died and over 140 people were injured. One more died a week later. The event was suspended. Buses and trains were mobilised to bring people home.

On June 28, 2012, three supercells affected the Midlands of England. One of them produced hailstones reported to be larger than golfballs, with conglomerate stones up to 10cms across. Burbage in Leicestershire saw some of the most severe hail. Another supercell produced a tornado near Sleaford, in Lincolnshire. Severe thunderstorms also affected the North East region of England. One such storm struck the Tyneside area without warning at the height of the evening rush hour causing widespread damage and travel chaos, with people abandoning cars and being trapped due to lack of public transport. Flooded shopping malls were evacuated, Newcastle Central station was shut, as was the Tyne and Wear Metro, and main road routes were flooded leading to massive tailbacks. 999 land line services were knocked out in some areas and the damage ran to huge amounts only visible the next day after water cleared. Many parts of County Durham and Northumberland were also affected, with thousands of homes across the North East left without power due to lightning strikes. Lightning was seen to hit the Tyne Bridge (Newcastle).

In Europe, the mini-supercell, or low-topped supercell, is very common, especially when showers and thunderstorms develop in cooler polar air masses with a strong jet stream above, especially in the left exit-region of a jetstreak.

North America

The Tornado Alley is a region of the central United States where severe weather is common, particularly tornadoes. Supercell thunderstorms can affect this region any time of the year, but are most common in the spring. Tornado watches and warnings are frequently necessary in the spring and summer. Most places from the Great Plains to the Eastern Seaboard and north as far as the Canadian prairies, Great Lakes region, and the St. Lawrence River will experience one or more supercells each year.

Gainesville, Georgia was the site of the fifth deadliest tornado in U.S. history in 1936, where Gainesville was devastated and 203 people were killed.21

The 1980 Grand Island tornado outbreak affected the city of Grand Island, Nebraska on June 3, 1980. Seven tornadoes touched down in or near the city that night, killing 5 and injuring 200.

The Elie, Manitoba tornado was an F5 that struck the town of Elie, Manitoba on June 22, 2007. While several houses were leveled, no one was injured or killed by the tornado.222324

A massive tornado outbreak of May 3, 1999 spawned an F5 Tornado in the area of Oklahoma City, OK that had the highest recorded winds on Earth. This outbreak spawned over 66 tornadoes in Oklahoma alone. On this day throughout the area of Oklahoma, Kansas, and Texas, over 141 tornadoes were produced. This outbreak resulted in 50 fatalities and 895 injuries.

A massive storm on June 16, 2012 struck much of Maine, causing widespread wind and flood damage.citation needed Many cities reported heavy flooding, with precipitation in excess of 15 inches. Wind speeds were reported in excess of 75 mph. Storm characteristics resembled that of a High Precipitation Supercell. No known tornadoes were reported.

A series of tornadoes which occurred on May 2013 caused severe devastation to Oklahoma City in general. The first tornado outbreaks occurred on May 18 to May 21 when a series of tornadoes hit. One of the storms formed an EF5 tornado also known as the Moore tornado which traveled across Oklahoma City causing a severe amount of disruption, the tornado was first spotted in Newcastle, it touched the ground for 39 minutes crossing through a heavily populated section of Moore, winds peaked 210 mph (340 km/h), 23 fatalities were caused and 377 injuries by the tornado. 61 other tornadoes were confirmed during the storm period and 95 were reported. Later on in the month on the night of 31 May 2013, another 9 deaths were confirmed from a series of tornadoes and funnel clouds which hit nearby areas.

South Africa

South Africa witnesses several supercell thunderstorms each year with the inclusion of isolated tornadoes. On most occasions these tornadoes occur in open farmlands and rarely cause damage to property, as such many of the tornadoes which do occur in South Africa are not reported. The majority of supercells develop in the central, northern, and north eastern parts of the country. The Free State, Gauteng, and Kwazulu Natal are typically the provinces where these storms are most commonly experienced, though supercell activity is most certainly not limited to these provinces. On occasion, hail reaches sizes in excess of golf balls, and tornadoes, though rare, also occur.

On the 6 May 2009 a well defined hook echo was noticed on local South African radars, along with satellite imagery this supported the presence of a strong supercell storm. Reports from the area indicated heavy rains, winds and large hail.25

On Sunday October 2, 2011 2 devastating tornadoes tore through two separate parts of South Africa on the same day, hours apart from each other. The first, classified as an EF 2 hit Meqheleng, the informal settlement outside Ficksburg, Free State which devastated shacks and homes, uprooted trees, and killed one small child. The second, which hit the informal settlement of Duduza, Nigel in the Gauteng province, also classified as EF2 hit hours apart from the one that struck Ficksburg. This tornado completely devastated parts of the informal settlement and killed two children, destroying shacks and RDP homes.2627


See also


  1. ^ Glickman, Todd S. (ed.) (2000). Glossary of Meteorology (2nd ed.). American Meteorological Society. ISBN 978-1-878220-34-9. 
  3. ^ NWS Louisville: Supercell Structure and Dynamics
  4. ^ Browning, K.A.; F.H. Ludlum (Apr 1962). "Airflow in Convective Storms". Quarterly Journal of the Royal Meteorological Society 88 (376): 117–35. doi:10.1002/qj.49708837602. 
  5. ^ Lemon, Leslie R.; C.A. Doswell (Sep 1979). "Severe Thunderstorm Evolution and Mesocyclone Structure as Related to Tornadogenesis". Mon. Wea. Rev. 107 (9): 1184–97. doi:10.1175/1520-0493(1979)107<1184:STEAMS>2.0.CO;2. 
  6. ^ "Thunderstorm in Victoria 06 Mar 2010". 2010-03-06. Retrieved 2012-03-11. 
  7. ^ National Weather Service (June 2009). "Hail spike". Glossary. National Oceanic and Atmospheric Administration. Retrieved 2010-03-03. 
  8. ^ Radar Characteristics Of Supercells
  9. ^ Davies, Jonathan M. (Oct 1993). "Small Tornadic Supercells in the Central Plains". 17th Conf. Severe Local Storms. St. Louis, MO: American Meteorological Society. pp. 305–9. 
  10. ^ Glickman, Todd S. (ed.) (2000). Glossary of Meteorology (2nd ed.). American Meteorological Society. ISBN 978-1-878220-34-9. 
  11. ^ City of Provo, Utah ::
  12. ^ - Storm Damage Estimated at $13 Million in Provo
  13. ^ Tornadoes Nature's Most Violent Storms
  14. ^ "Maharashtra monsoon 'kills 200' ", BBC News, July 27, 2005
  15. ^ "Record Stormy February in Canberra". 
  16. ^ "Severe Thunderstorms in Melbourne 6 March 2010". Bureau of Meteorology. Retrieved 6 March 2010. 
  17. ^ "Perth reeling from freak storm". ABC Online. 23 March 2010. Retrieved 27 March 2010. 
  18. ^ Saminather, Nichola (23 March 2010). Perth Storms Lead to A$70 Mln of Insurance Claims in 24 Hours. Bloomberg L.P. Retrieved 27 March 2010 
  19. ^ kh (2009-05-26). "Goederentrein van de sporen geblazen in Lillo" [Packtrain blown from tracks in Lillo]. De Morgen (in Dutch) (Belga). Retrieved 2011-08-22. 
  20. ^ Hamid, Karim; Buelens, Jurgen (September 2009). "De uitzonderlijke onweerssituatie van 25-26 mei 2009" [The exceptional situation of thunderstorms 25 to 26 May 2009]. Meteorologica (in Dutch) (Nederlandse Vereniging van BeroepsMeteorologen) 18 (3): 4–10. Retrieved 2011-08-22. 
  21. ^ NOAA Storm Prediction Center
  22. ^ Elie tornado now Canada's first F5
  23. ^ Elie Tornado Upgraded to Highest Level on Damage Scale
  24. ^ | "Manitoba twister classified as extremely violent"
  25. ^ Storm Chasing South Africa - 6 May Supercell
  26. ^ Tornadoes kill two, destroy more than 1,000 homes
  27. ^ 113 hurt in Duduza tornado

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