Draft:2011 Enterprise tornado

Draft:2011 Enterprise tornado

The tornado, as it was in southeast Mississippi.
Meteorological history
Formed	April 27, 2011, 5:42 p.m. CDT (UTC−05:00)
Dissipated	April 27, 2011, 8:35 p.m. CDT (UTC−05:00)
Duration	2 hours, 53 minutes
EF4 tornado
on the Enhanced Fujita scale
Highest winds	175 mph (282 km/h)
Overall effects
Fatalities	7
Injuries	17

Meteorological synopsis

Significant severe weather was ongoing early on April 27 (in the overnight hours) and continued for the entire calendar day virtually unbroken. For the second day in a row, the SPC issued a high risk of severe weather for the Southern United States. Later that morning, the SPC even increased the probability for tornadoes to 45 percent along a corridor from Meridian, Mississippi, to Huntsville, Alabama, an extremely rare issuance exceeding the high risk standards. Conditions became increasingly favorable for tornadoes during such an extreme tornado outbreak.

During the early morning hours, a cold front with several embedded low pressure areas extended from east Texas northeastward into the Ohio River Valley. An upper-level disturbance that had moved across the frontal boundary the previous evening sparked an area of thunderstorms that morphed into a squall line. This line of severe thunderstorms would produce tornadic activity from the evening on April 26 into the late morning of April 27. Early in the morning the squall line, packing straight-line winds and numerous embedded tornadoes, moved through Louisiana and Mississippi before proceeding to affect North and Central Alabama and parts of Middle and East Tennessee. The line strengthened as it moved through Alabama, partially due to a high amount of low-level moisture from the Gulf of Mexico and increasing wind shear.

From the late morning to the early afternoon, another squall line moved through northern parts of Mississippi and Alabama as high wind shear and low-level moisture persisted. However, this time several discrete supercells developed along and in front of the line, spawning seven weak tornadoes across Morgan, Limestone, and Madison Counties in northern Alabama around noon that day.

The most intense supercells of the outbreak developed around midday in central Mississippi and began tracking eastward. With the extreme instability and wind shear, they quickly intensified and eventually became tornadic, shortly thereafter resulting in strong to violent tornadoes. Responding to the high risk issued by the SPC and the already unstable atmosphere expected to become even more unstable throughout the afternoon hours, a PDS tornado watch was issued at 1:45 p.m. CDT (18:45 UTC) for much of Alabama and portions of Mississippi, Tennessee, and Georgia. A widespread complex of supercell storms overspread the states of Mississippi and Alabama and violent tornadoes began rapidly touching down as the afternoon progressed.

By mid-afternoon, as wind shear and low-level moisture continued to dramatically increase, a tornado emergency was declared for Neshoba County, Mississippi, as a large tornado was reported on the ground by both storm spotters and a camera atop a television tower from ABC affiliate WTOK-TV (channel 11) in Meridian, Mississippi. This powerful EF5 tornado caused incredible damage northeast of Philadelphia, Mississippi, where pavement was torn off from roads, vehicles were thrown, and the ground was scoured out to a depth of 2 feet (0.61 m) by the tornado. Three people died when a mobile home was thrown 300 yards (270 m) into a wooded area, obliterating it in the process. A supercell would also produce the Enterprise tornado at around the same time.

Tornado summary

Low-end EF4 damage to a home near Enterprise, Mississippi.

This extremely long-tracked, violent EF4 tornado touched down near Raleigh, Mississippi, in Smith County at 5:42 p.m. CDT (22:42 UTC), and continued into the Uniontown, Alabama, area before dissipating. The tornado initially downed trees, blew skirting from mobile homes, and tore shingles from roofs. The tornado intensified as it moved northeast across Smith County and produced up to EF2 and EF3 damage. One mobile home was picked up, bounced a couple times, and thrown into a tree line, where it was torn apart and debris was scattered up to a mile away, including the frame. The tornado mowed down a stand of pine trees and destroyed two frame houses, with major damage to the interior walls, and the exterior walls completely destroyed. Many power poles were snapped, a mobile home was annihilated, and a large shop building was completely destroyed as well. It then moved into Jasper County and snapped and debarked many pine trees. The first area of EF4 damage was observed near Louin as a frame home and several mobile homes were completely destroyed, with parts of the mobile homes being thrown long distances, and some of the frame home foundation being swept clean. The tornado caused significant damage to a poultry farm and cattle ranch before it weakened briefly. It then destroyed two mobile homes and caused extensive tree and power line damage. The tornado then produced a relatively narrow path of EF1-strength tree and power line damage for several miles, until re-intensifying near to EF3 strength near Rose Hill.

Southeast of Rose Hill, the tornado removed most of the roof of a frame home and caused heavy damage to the exterior walls, took a large section of roof off another frame home, completely destroyed a large mobile home, and caused extensive tree damage. The tornado then weakened again and entered Clarke County as an EF0 while only downing a few trees. The tornado strengthened again and downed trees and power lines as it crossed Interstate 59. Several other homes and mobile homes were destroyed as the tornado moved along the south side of Enterprise. At the same time, Sean Casey of Team TIV shot the tornado with his new 3D camera as it was crossing I-59, making this the first tornado ever shot in 3D. Another area of EF4 damage was observed east of Enterprise as a new home undergoing completion was leveled, with the debris swept off the foundation. Many more frame homes were heavily damaged nearby. Many mobile homes were destroyed and trees were downed in this area as well. It then weakened slightly to EF3 strength and produced heavy damage to more houses and mobile homes near Snell and Energy. It also downed many more trees and power lines before moving into Choctaw County, Alabama, southwest of Yantley. The tornado killed seven people and injured fourteen others on its 65-mile (105 km) portion of the path that was in Mississippi.

In Choctaw County, the tornado traveled 27.5 miles (44.3 km) as it caused extensive damage to homes (one of which was destroyed at EF3 strength), and numerous other structures. Several mobile homes were destroyed and many trees were either snapped or completely uprooted. The tornado then moved into Sumter County. In Sumter County, the tornado caused significant damage to homes and mobile homes before it crossed the Tombigbee River and moved into Marengo County. It continued causing significant tree damage as well as destroying several homes and outbuildings along a 26.7-mile (43.0 km) path in this county. The tornado then entered Perry County, the final portion of the path, where it damaged two outbuildings and a grain silo as well as causing significant tree damage before lifting just north of Uniontown at 8:35 p.m. CDT (01:35 UTC). The damage in Sumter, Marengo, and Perry Counties was rated EF2. The tornado was on the ground for nearly three hours, having traveled 122.04 miles (196.40 km) across seven counties in two states. Seven people were killed and another 17 were injured.