Instruct: Given a question, retrieve relevant documents that can help answer the question.
Query: What country has the most tornadoes?
The United States averaged 1,274 tornadoes per year in the last decade while Canada reports nearly 100 annually (largely in the southern regions). However, the UK has most tornadoes per area per year, 0.14 per 1000km², although these tornadoes are generally weak, and many other European countries have a similar number of tornadoes per area.[1]
Tornadoes occur frequently in Alabama during the spring and fall months, these tornadoes can be devastating and even deadly.– these are common throughout the state, although the peak season for tornadoes varies from the northern to southern parts of the state. Alabama, along with Kansas, has the most reported F5/EF5 tornadoes than any other state – according to statistics from the National Climatic Data Center for the period January 1, 1950, to October 31, 2006. An F5 tornado is the most powerful of its kind. Several long – tracked F5 tornadoes have contributed to Alabama reporting more tornado fatalities than any other state except for Texas and Mississippi. The Super Outbreaks of April 1974 and April 2011 both badly affected Alabama. The northern part of the state – along the Tennessee Valley – is one of the areas in the US most vulnerable to violent tornadoes . The area of Alabama and Mississippi most affected by tornadoes is sometimes referred to as Dixie Alley, as distinct from the Tornado Alley of the Southern Plains. Alabama is one of the few places in the world that has a secondary tornado season (November and December) along with the spring severe weather season.
Tornadoes create different damage depending on how fast their wind speeds are. The Fujita Scale classifies a tornado by its wind speeds. For example, if the tornado's wind speeds are low, then it is classified as a F0 tornado. If the tornado's wind speeds are about 200 miles per hour or at 200 miles per hour, then it is classified as a F5 tornado. In the United States, tornadoes have been known to form at high and low intensities. The probability of a high intensity or violent tornado differs by location across the country. For example, due to the high frequency of tornadoes in the "Tornado Alley" area mentioned before, a more violent tornado would be more likely to form there due to the strength of the thunderstorms produced by the two bordering air masses. The states with the highest number of F5 and EF5 rated tornadoes since data was available in 1950 are Alabama and Oklahoma, each with seven tornadoes. Iowa, Kansas, and Texas each are tied for second most with six. The state with the highest number of F5 and EF5 tornadoes per square mile, however, was Iowa. The state with the most number of tornadoes classified as "violent", or F4 and F5, is Kentucky, and the state with the highest average intensity ranking for tornadoes is Alabama.
As with most of the northeastern United States, the number of tornadoes peaks in the summer months, normally in July or August. Hartford County has had the most tornadoes in the state, although since 1950 Litchfield County has reported the most tornadoes. Several areas have been struck more than once, and Waterbury has been struck by no less than four tornadoes since 1955.
This page lists tornadoes and tornado outbreaks which have touched down in Canada prior to the 21st century. On average, there are around 80 confirmed and unconfirmed tornadoes that touch down in Canada each year, with most occurring in Southern Ontario, the southern Canadian Prairies and southern Quebec. Canada ranks as the country with the second most tornadoes per year, after the US. The most common types are F0 to F2 in damage intensity level and usually result in minor structural damage to barns, wood fences, roof shingles, chimneys, uprooted or snapped tree limbs and downed power lines. Fewer than 5% of tornadoes in Canada are rated F3 or higher in intensity, where wind speeds are in excess of . Prior to April 1, 2013, Canada used a slightly modified Fujita scale, and as of that date the Enhanced Fujita scale, again slightly modified, was put into use to rate tornado intensity, based on the damage to buildings and vegetation.
Bangladesh is one of the countries with the highest frequency of tornadoes, behind the United States and Canada. Bangladesh has received other deadly tornadoes, but this particular storm was the worst in the country's history.
The United Kingdom has the highest incidence of tornadoes, measured by unit area of land, than any other country in the world.[86] Unsettled conditions and weather fronts transverse the Islands at all times of the years and are responsible for spawning the tornadoes, which consequently form at all times of the year. The United Kingdom has at least 34 tornadoes per year and possibly as many as 50,[87] more than any other country in the world relative to its land area. Most tornadoes in the United Kingdom are weak, but they are occasionally destructive. For example, the Birmingham tornado of 2005 and the London tornado of 2006 both registered F2 on the Fujita scale and both caused significant damage and injury.[88]
This page documents notable tornadoes and tornado outbreaks worldwide in 1973, but mostly features events in the United States. According to tornado researcher Thomas P. Grazulis, documentation of tornadoes outside the United States was historically less exhaustive, owing to the lack of monitors in many nations and, in some cases, to internal political controls on public information. Most countries only recorded tornadoes that produced severe damage or loss of life. Consequently, available documentation in 1973 mainly covered the United States. On average, most recorded tornadoes, including the vast majority of significant—F2 or stronger—tornadoes, form in the U.S., although as many as 500 may take place internationally. Some locations, like Bangladesh, are as prone to violent tornadoes as the U.S., meaning F4 or greater events on the Fujita scale.
The most unusual tornado event of the year occurred on August 19. Seven tornadoes were recorded in Minnesota that day, including one that touched down in Minneapolis. What made this day unusual is that a unique atmospheric setup allowed several of the tornadoes to be spawned from rain showers where no lightning was present.
The Southern United States has suffered more tornado fatalities than any other part of the country. Some areas experience repeated damaging tornado events, such as the Tennessee Valley and in northern Alabama. The state of Alabama is tied for the most reported F5 tornadoes. For the period 1950 to 2006, three hundred and fifty eight people were killed by tornadoes in Alabama, ranking the state third nationwide behind Texas (521) and neighboring Mississippi (404). Fourth is Arkansas (336) and fifth is Tennessee with 271 fatalities.
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 1896 St. Louis–East St. Louis tornado on May 27, incurred the most damages adjusted for wealth and inflation, at an estimated $2.9billion (1997USD). 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 (2011 USD). Until 2011, the "Bridge Creek-Moore tornado" of May 3, 1999 was the most damaging.[12]
The United States averaged 1,274 tornadoes per year in the last decade. April 2011 saw the most tornadoes ever recorded for any month in the US National Weather Service's history, 875; the previous record was 542 in one month.[16] It has more tornadoes yearly than any other country and reports more violent (F4 and F5) tornadoes than anywhere else.
In what was apparently an intense tornado outbreak sequence, other major tornado outbreaks occurred on May 15, May 17, and May 24–25, with other smaller outbreaks during the month as well. The middle to end of May was extremely active but sparse records preclude knowing much detail. Tom Grazulis has stated that the week of May 24–28 was "perhaps the most violent single week of tornado activity in US history".
The Netherlands has the highest average number of recorded tornadoes per area of any country in the world (more than 20, or 0.0005 per km), annually), followed by the UK (around 33, or 0.0001 per km), per year), but most are small and cause minor damage. In absolute number of events, ignoring area, the UK experiences more tornadoes than any other European country, excluding waterspouts. Europe uses its own tornado scale, known as the TORRO scale, which ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes.
On May 30, 1998, the most destructive and second deadliest tornado in South Dakota history struck Spencer. It began as a large, dust-cloaked tornado NW of Farmer, South Dakota in Hanson County, concurrent with the demise of the "Fulton" tornado. Continuing toward the ESE, it struck several farmsteads before crossing the Hanson/McCook County line a half mile WNW of Spencer. At this time, the tornado was being observed by the OU Doppler on Wheels crew, whose mobile Doppler radar data showed up to 264 mph winds in the tornado a few tens of meters above ground level. The population of the town diminished soon after to less than half of what it was previous to the tornado, from 315 to 145 in April 1999, and has since hovered around that mark.
Scattered tornadoes were reported across the US, but most were weak or remained over open country. However one tornado caused EF2 damage in the town of Bardwell, Kentucky. Another EF2 tornado destroyed airplane hangars near Cairo, Illinois. These later tornadoes were not part of the same weather system as the earlier tornadoes; they were part of a weather system that led to the 2011 Super Outbreak.
It is internationally recognised that the United Kingdom has a higher incidence of tornadoes, measured by unit area of land, than any other country in the world. Dr T. Theodore Fujita (inventor of the Fujita scale), an American meteorologist, was the first to recognise the UK as the top site for tornadoes in 1973. The United Kingdom has at least 33 tornadoes per year, more than any other country in the world relative to its land area. Although most tornadoes are weak, there are occasional destructive events, for example, the Birmingham tornado of 2005 and the London tornado of 2006. Both registered F2 on the Fujita scale and both caused significant damage and injury. The largest ever recorded was thought to have been an F4, again in London in 1091. The most deadly occurred on 28 December 1879. All 74 lives were lost when a passenger train plunged from the Tay Bridge (Tayside) into the Tay Estuary, when the middle section of the bridge collapsed. Although the bridge was poorly constructed and had already been weakened in earlier gales (including the pre-existing winds at the time of the tragedy), the ultimate failure is believed to have been caused by two or three waterspouts which were sighted close to the bridge immediately before the accident. A tornado also developed in London on 3 July 2007.
The UK also holds the title for the highest known 'outbreak' of tornadoes outside of the United States. The largest tornado outbreak in Britain is also the largest tornado outbreak known anywhere in Europe. On 23 November 1981, 105 tornadoes were spawned by a cold front in the space of 5.25 hours. Excepting Derbyshire, every county in a triangular area from Gwynedd to Humberside to Essex was hit by at least one tornado, while Norfolk was hit by at least 13. Very fortunately most tornadoes were short-lived and also weak (the strongest was around T5 on the TORRO Tornado Scale) and no deaths occurred.
While it is unlikely that the 1979 storm was as powerful as the 1946 Windsor-Tecumseh, Ontario tornado (where it has been speculated that F5 damage took place), the most glaring difference was that of path width. Whereas the damage paths of the 1946, 1953, and 1985 tornadoes remained under one kilometre, the Woodstock one was more massive in size. In some cases its width approached one mile, likely making it one of the largest tornadoes documented in Canada alongside the July 1987 Edmonton Tornado. Environment Canada places the 1979 Woodstock tornado as the eleventh worst in the country's history.http://www.simcoereformer.ca/2009/08/26/memories-whirl-of-tornado-79
Though Windsor had CKLW as a radio station from Detroit, Michigan, there were no records kept from them. CBC Toronto was the only radio station that has kept their archives for the reports on this event. CBC Archives helps to explain what happened in Windsor the day after on Windsor, Ont. struck by tornado in 1946. The report explains what happened, how many were killed, how citizens feel and even what was stolen and who came out to help. In addition to this report, there were many reports to explain how the tornado was formed for this tornado. The reports also hold onto interviews from people who viewed the tornado first hand.
In the United States over 80 deaths and 1,500 injuries are associated with tornadoes each year. According to the National Oceanic Atmospheric Administration, most tornado deaths are caused by people not following instructions on what to do the right way. They also mention that some people are not even warned that a tornadic storm is coming, while others get a warning but do not believe that a tornado will hit their area. In 2012, 68 people were killed by tornadoes in the United States. Kentucky had the most fatalities, 22. Kentucky was followed by Indiana (13), Illinois (9), Missouri and Oklahoma (6), Ohio (4), Alabama and Tennessee (3), and Florida and Kansas (1).
Tornadoes have been recorded on all continents except Antarctica and are most common in the middle latitudes where conditions are often favorable for convective storm development.[1] The United States has the most tornadoes of any country, as well as the strongest and most violent tornadoes. A large portion of these tornadoes form in an area of the central United States popularly known as Tornado Alley.[2] Other areas of the world that have frequent tornadoes include significant portions of Europe, South Africa, Philippines, Bangladesh, parts of Argentina, Uruguay, and southern and southeast Brazil, northern Mexico, New Zealand, and far eastern Asia.[3][4]
The United States has the most tornadoes of any country, nearly four times more than estimated in all of Europe, excluding waterspouts.[67] This is mostly due to the unique geography of the continent. North America is a large continent that extends from the tropics north into arctic areas, and has no major east-west mountain range to block air flow between these two areas. In the middle latitudes, where most tornadoes of the world occur, the Rocky Mountains block moisture and buckle the atmospheric flow, forcing drier air at mid-levels of the troposphere due to downsloped winds, and causing the formation of a low pressure area downwind to the east of the mountains. Increased westerly flow off the Rockies force the formation of a dry line when the flow aloft is strong,[68] while the Gulf of Mexico fuels abundant low-level moisture in the southerly flow to its east. This unique topography allows for frequent collisions of warm and cold air, the conditions that breed strong, long-lived storms throughout the year. A large portion of these tornadoes form in an area of the central United States known as Tornado Alley.[69] This area extends into Canada, particularly Ontario and the Prairie Provinces, although southeast Quebec, the interior of British Columbia, and western New Brunswick are also tornado-prone.[70] Tornadoes also occur across northeastern Mexico.[5]
On average, there are around 80 confirmed and unconfirmed tornadoes that touch down in Canada each year, with most occurring in Southern Ontario, the southern Canadian Prairies and southern Quebec. Canada ranks as the second country in the world with the most tornadoes per year, after the US. The most common types are F0 to F2 in damage intensity level and usually result in minor structural damage to barns, wood fences, roof shingles, chimneys, uprooted or snapped tree limbs and downed power lines. Fewer than 5% of tornadoes in Canada are rated F3 or higher in intensity, where wind speeds are in excess of . Prior to April 1, 2013, Canada used a slightly modified Fujita scale, and as of that date the Enhanced Fujita scale, again slightly modified, was put into use to rate tornado intensity, based on the damage to buildings and vegetation.
Oklahoma City has a very active severe weather season from March through June, especially during April and May. Being in the center of what is colloquially referred to as Tornado Alley, it is prone to especially frequent and severe tornadoes, as well as very severe hailstorms and occasional derechoes. Tornadoes have occurred in every month of the year and a secondary smaller peak also occurs during autumn, especially October. The Oklahoma City metropolitan area is one of the most tornado-prone major cities in the world, with about 150 tornadoes striking within the city limits since 1890. Since the time weather records have been kept, Oklahoma City has been struck by thirteen violent tornadoes, eleven F/EF4s and two F/EF5s.
There were 1,692 tornadoes confirmed in the United States in 2008, with 126 confirmed fatalities. This made 2008 the deadliest year in that country since 1998. Nine other fatalities have been reported elsewhere in the world: three in France, two each in Bangladesh and Poland and one each in Russia and China. With 1,692 confirmed tornadoes, 2008 ranked as the third most active US tornado season on record, only 2011 and 2004 have had more tornadoes confirmed with 1,697 and 1,817, respectively. The US state of Kansas received the most tornadoes in the United States in 2008 with 187.