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"Dixie Alley" is a colloquial term sometimes used for areas of the
southern United States The Southern United States (sometimes Dixie, also referred to as the Southern States, the American South, the Southland, Dixieland, or simply the South) is List of regions of the United States, census regions defined by the United States Cens ...
which are particularly vulnerable to strong to violent
tornado A tornado is a violently rotating column of air that is in contact with the surface of Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the ...
es. Some argue this is distinct from the better known "
Tornado Alley Tornado Alley, also known as Tornado Valley, is a loosely defined location of the central United States and, in the 21st century, Canada where tornadoes are most frequent. The term was first used in 1952 as the title of a research project to st ...
" and that it has a high frequency of strong, long-track tornadoes that move at higher speeds. The term was coined by National Severe Storms Forecast Center (NSSFC) Director Allen Pearson after witnessing a tornado outbreak which included more than 9 long-track, violent tornadoes that killed 121 on February 21–22, 1971. The specific characteristics of the Southeast led to VORTEX-SE, a field project studying
tornadogenesis Tornadogenesis is the process by which a tornado forms. There are many types of tornadoes, varying in methods of formation. Despite ongoing scientific study and high-profile research projects such as VORTEX projects, VORTEX, tornadogenesis is a ...
, diagnosis and forecasting, in addition to social science implications, and examines both
supercell A supercell is a thunderstorm characterized by the presence of a mesocyclone, a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms (su ...
ular tornadoes and those resulting from quasi-linear convective system (QLCS) thunderstorm structures. This was followed a few years later by another major field project, PERiLS, focusing on QLCS tornadoes.


Geography

Dixie Alley includes much of the area of the lower
Mississippi Valley The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...
. It stretches from eastern
Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
and
Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...
across
Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...
,
Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...
,
Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...
,
Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...
,
Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...
, and mid to western
Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...
to upstate
South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...
and western
North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...
; the area reaches as far north as southeast
Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...
. Another source places all of Arkansas within Dixie Alley. Although tornadoes are less frequent in these states than they are in the southern Plains, the southeastern states have had more tornado-related deaths than any of the Plains states (excluding
Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
). This is partly due to the fact that there are relatively high numbers of strong/violent long tracked tornadoes and higher population density of this region, as well as the Southern United States having the highest percentage of
manufactured homes Manufactured housing (commonly known as mobile homes in the United States) is a type of prefabricated housing that is largely assembled in factories and then transported to sites of use. The definition of the term in the United States is regul ...
in the US, where 63% of the overall tornado-related fatalities occur. According to the
National Climatic Data Center The United States National Climatic Data Center (NCDC), previously known as the National Weather Records Center (NWRC), in Asheville, North Carolina, was the world's largest active archive of weather data. In 2015, the NCDC merged with two other ...
(NCDC), for the period January 1, 1950 – October 31, 2006, Alabama and
Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...
received the largest number of F5 tornadoes. Complicating matters is that tornadoes are rarely visible in this area, as they are more likely to be rain-wrapped, embedded in shafts of heavy rain, and that the hilly
topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the landforms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...
and heavily forested landscape makes them difficult to see.


Prevalent tornado characteristics

Dixie Alley is part of a region of enhanced tornadic activity extending between the Appalachian and Rocky Mountains, but tornadoes and outbreaks in the Dixie Alley region exhibit some statistically distinguishable characteristics from the more well known Tornado Alley. Tornadic storms in Dixie Alley are most often high precipitation supercells due to an increase of moisture from proximity to the nearby
Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
. The Dixie Alley tornadoes accompanying the HP supercells are often partially or fully wrapped in rain, impairing the visibility of the tornadoes to storm spotters and chasers, law enforcement, and the public. Increases of warmth and
instability In dynamical systems instability means that some of the outputs or internal states increase with time, without bounds. Not all systems that are not stable are unstable; systems can also be marginally stable or exhibit limit cycle behavior. ...
in conjunction with strong
wind shear Wind shear (; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical ...
in the Dixie Alley region impacts the times when tornadoes form. In the traditional Tornado Alley, tornadoes most often form from the mid afternoon to early evening. Dixie Alley's instability can be maintained long after sunset due to being adjacent to the Gulf, increasing the frequency of intense nighttime and early morning tornadoes. There is also a less focused
tornado season Tornadoes have been recorded on all continents except Antarctica. They are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as we ...
which tends to be most active in early spring and late autumn but can continue throughout the winter and into late spring, which can lead to complacency among residents of the region. The region often is subject to tornadoes much earlier than the general national peak from May and June, usually from February to Mid-April, and several notorious outbreaks have struck during the late winter and early spring and also in late fall. The complacency situation was noted after the
2008 Super Tuesday tornado outbreak The 2008 Super Tuesday tornado outbreak was a deadly tornado outbreak which affected the Southern United States and the lower Ohio Valley on February 5 and 6, 2008. The event began on Super Tuesday, 2008, Super Tuesday, while 24 states in t ...
in February 2008 that hit the Dixie Alley killing 57 people, many people indicated that they had underestimated the threat of severe weather on that day since it was well before the peak of tornado season. A 2018 study found in the U.S. an overall eastward shift of tornado frequency and impacts – toward Dixie Alley. The study found relatively-lower tornado frequency and impacts in parts of the traditional
Tornado Alley Tornado Alley, also known as Tornado Valley, is a loosely defined location of the central United States and, in the 21st century, Canada where tornadoes are most frequent. The term was first used in 1952 as the title of a research project to st ...
, especially areas from north-central Texas toward the Houston, Texas area, and relatively-higher tornado frequency and impacts in parts of the Mid-South, especially eastern Arkansas, the greater
Memphis, Tennessee Memphis is a city in Shelby County, Tennessee, United States, and its county seat. Situated along the Mississippi River, it had a population of 633,104 at the 2020 United States census, 2020 census, making it the List of municipalities in Tenne ...
area, Western Kentucky, and northern Mississippi – all areas near the heart of Dixie Alley (see especially Figure 4). Variations in
climate pattern Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more ...
s and
teleconnection Teleconnection in atmospheric science refers to climate anomalies being related to each other at large distances (typically thousands of kilometers). The most emblematic teleconnection is that linking sea-level pressure at Tahiti and Darwin, Aust ...
s, such as the
El Niño–Southern Oscillation El Niño–Southern Oscillation (ENSO) is a global climate phenomenon that emerges from variation in winds and sea surface temperatures over the tropical Pacific Ocean. Those variations have an irregular pattern but do have some semblance of cyc ...
(ENSO) can also have significant impacts on tornadic activity in the region from year to year.
Climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
is also expected to affect tornado activity in the region.


Notable outbreaks

Dixie Alley has been subject to numerous
tornado outbreak A tornado outbreak is the occurrence of multiple tornadoes spawned by the same Synoptic scale meteorology, synoptic scale weather system. The number of tornadoes required to qualify as an outbreak typically are at least six to ten, with at least ...
s throughout history, including very intense outbreaks and those of very large spatial and temporal extent. Notorious outbreaks affecting the region include: the Great Natchez Tornado, the 1884 Enigma tornado outbreak, the
April 1924 tornado outbreak On April 29–30, 1924, an outbreak of at least 28 tornadoes—26 of which were significant, meaning F2 or stronger—affected the Southern United States. The tornadoes left 114 dead and at least 1,166 injured, mostly in th ...
, the 1932 Deep South tornado outbreak, the 1936 Tupelo–Gainesville tornado outbreak, the April 1957 Southeastern tornado outbreak, the 1984 Carolinas tornado outbreak, and the November 1992 tornado outbreak. The
1974 Super Outbreak The 1974 Super Outbreak was one of the most intense tornado outbreaks on record, occurring on April 3–4, 1974, across much of the United States. It was one of the deadliest tornado outbreaks in U.S. history. It was also the most violent t ...
also hit the area very hard, producing multiple F5 tornadoes in Alabama, and F4 tornadoes in North Georgia and the Appalachian southwest of North Carolina. More recently the region was hit by the 2008 Super Tuesday tornado outbreak followed by the tornado outbreak of April 14–16, 2011, the deadliest since the 2008 outbreak. Two weeks after the April 14–16 event, Dixie Alley was the epicenter of the
2011 Super Outbreak The 2011 Super Outbreak was the largest, costliest, and one of the deadliest tornado outbreaks ever recorded, taking place in the Southern, Midwestern, and Northeastern United States from April 25 to 28, 2011, leaving catastrophic destruc ...
, which was the largest tornado outbreak ever recorded, as well as the fourth-deadliest outbreak in United States history, with over 300 people dead. The Easter 2020 Tornado Outbreak also happened in Dixie Alley. It spawned over 100 tornadoes and has a spot in the top most tornadoes in 24 hours in an outbreak.


See also

* List of tornadoes and tornado outbreaks *
Tornado climatology Tornadoes have been recorded on all continents except Antarctica. They are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as we ...
* Hailstorm Alley


References

{{reflist, 2 Tornado Regions of the United States