A deadly tornado outbreak affected the Southern United States and the lower Ohio Valley on February 5 and 6, 2008. The outbreak began on Super Tuesday, while 24 states in the United States were holding primary elections and caucuses to select the presidential candidates for the upcoming presidential election. Missouri, Illinois, Arkansas, Alabama, and Tennessee were among the affected regions in which primaries were being held. Some voting locations were forced to close early due to the approaching severe weather.
The outbreak generated 86 tornadoes between 21:00 UTC 5 February and 13:00 UTC 6 February. The storm system produced several destructive tornadoes in heavily populated areas, most notably in the Memphis metropolitan area, in Jackson, Tennessee, and the northeastern end of the Nashville metropolitan area.
A total of 57 people were killed across four states and 18 counties, with hundreds of others injured. The outbreak, at the time, was the deadliest in the era of modern NEXRAD doppler radar, which was fully implemented in 1997. The event was the second deadliest in February since 1950 behind the 1971 Mississippi Delta tornado outbreak, which killed 123, the deadliest outbreak in both Tennessee and Kentucky since the 1974 Super Outbreak, and was at the time the deadliest tornado outbreak in the US overall since the 1985 United States–Canada tornado outbreak which killed 76 people. This record would not be surpassed until the 2011 Super Outbreak which killed 324 people. Damage from tornadoes was estimated at over $500 million (2008 USD).Storm Events database National Climatic Data Center. Accessed May 13, 2008.
The weather system which produced the tornadoes caused significant straight-line wind damage, hail as large as softballs – in diameter – major flooding, significant freezing rain, and heavy snow across many areas of eastern North America. The total damage from the entire weather system reached $1.2 billion.
Meteorological synopsis
A series of strong low pressure systems formed across the southern Great Plains on February 4, contributing to record warmth on February 4 and 5 in the southern Plains and lower Mississippi River Valley. High temperatures across many areas reached the 70s°F (21–26 °C), and in Alabama temperatures reached the low 80s°F (27 °C) with dew points in the middle 60s° (17–20 °C). Dewpoints in the mid 60s°F were recorded as far north as Memphis. A strong cold front trailing the low-pressure area approached the region from the west.
As the surface low progressed northeast, a strong jet streak was positioned over the warm sector, with winds moving East which was perpendicular to the direction of the surface winds, which were out at the southeast. This sharp change in winds resulted in much wind shear and wind profiles favoring rotating supercells capable of producing significant tornadoes. The strong jet stream also provided tons of lift, favoring supercells to form in the open warm sector with instability across the outbreak area. CAPE values, a measurement of the level of tropospheric instability, was well over 1000 J/kg, and Storm Relative Helicity, a measurement of the potential for rotating winds, reached over 200 m2/s².
On February 5 at 6:39 am CST (1239 UTC), the Storm Prediction Center (SPC) issued a high risk of severe storms for most of Arkansas, the first in February since 1998. At 10:16 am CST (1616 UTC), the high risk area was extended farther northeast to include western Kentucky, northwestern Mississippi, the Missouri Bootheel, West Tennessee, and Southern Illinois. A moderate risk of severe weather was issued for northwestern Alabama, the rest of Arkansas, the rest of southern Illinois, southern Indiana, most of the rest of Kentucky, northern Louisiana, central Mississippi, parts of southeastern Missouri, southwestern Ohio, eastern Oklahoma, middle Tennessee and northeastern Texas. A total of fifteen watches were issued by the SPC during the outbreak, including thirteen tornado watches (two of which were PDS watches) and two severe thunderstorm watches.
Early on the morning of February 5, a squall line developed across eastern Texas northward into Missouri and moved east towards the high risk area. Ahead of the squall line, the cap took longer than expected to break, but when it finally did in the late afternoon hours, numerous supercell thunderstorms quickly formed across Arkansas and southern Missouri. The first tornadoes touched down around 3:30 pm CST (2130 UTC). A cap is a layer of relatively warm air aloft (usually several thousand feet above the ground) which suppresses or delays the development of thunderstorms; the cap often prevents or delays thunderstorm development even in the presence of extreme instability. However, if the cap is removed or weakened, then explosive thunderstorm development can occur. Some of the most powerful tornado-producing supercells were situated across the Memphis and Jackson areas, as well as central Arkansas (one producing a tornado that tracked and lasted about two hours) between 5:00 and 7:30 pm CST (2300 to 0130 UTC) while numerous other tornadoes were reported across northern Mississippi northwest of Tupelo, Mississippi, early in the evening. As the evening progressed, one of these supercells traveled across Middle Tennessee including the Nashville metropolitan area and south-central Kentucky, where several deadly tornadoes were reported during the evening hours between 7:30 pm and 11:00 pm CST (0130 to 0500 UTC) Meanwhile, the squall line that developed from near Dallas to Kansas City moved eastward throughout the late evening and overnight hours causing numerous reports of damaging wind along with many spin-up tornadoes from Louisiana to Ohio and Indiana. It then moved through the southeast U.S. during the early morning hours. Additional strong thunderstorms developed ahead of the front across the southeast during the overnight and early morning hours. A record (at the time) of five tornado emergency declarations were issued on February 5; four for Tennessee, and one in Alabama.
On February 6, a slight risk of severe weather was issued for much of the eastern United States from Pennsylvania to the Florida Panhandle as the squall line raced eastward ahead of the cold front. After several additional tornadoes touched down in Alabama during the early morning hours just before dawn, the primary severe weather threat became damaging wind across the Mid-Atlantic States. No additional tornadoes were reported during the late morning and afternoon as the cold front exited into the Atlantic Ocean, although wind damage was reported across eastern Kentucky, eastern Pennsylvania and most of Georgia. Farther north, snow and freezing rain, at times heavy, continued from Iowa to Quebec until February 7 as the center of the system moved slowly out of the area.
Confirmed tornadoes
Atkins–Clinton–Mountain View–Highland, Arkansas
The first long-lived supercell, which spawned the tornado with the longest continuous track of any single tornado to occur during this outbreak, developed around 4:50 p.m. CST (2250 UTC) southeast of Centerville in Yell County, Arkansas. The tornado touched down to the southwest of New Neely, causing minor damage to two structures and downing trees at EF0 to EF1 strength. The tornado tracked into Pope County, rapidly intensifying to EF3 strength as it slammed into Lucky Landing, a marina at Lake Atkins, where one woman was killed. Continuing northeast, the tornado struck the southern and eastern outskirts of Atkins, killing three people. Northeast of Atkins, the tornado toppled metal truss towers, destroyed chicken houses, and heavily damaged a large church and gym. In the Happy Bend area, another fatality occurred as a man abandoned his mobile home and sought shelter in a large metal shipping container, which was tossed hundreds of yards into a wooded area.
The tornado intensified to EF4 strength as it entered Van Buren County and tore through the south edge of Clinton, killing three people in the vicinity. The tornado maintained EF4 intensity as it continued into Stone County, slamming into the town of Mountain View. In the Mountain View area, 38 homes and mobile homes were destroyed, 15 sustained major damage, and 15 sustained minor damage. The tornado weakened slightly to high-end EF3 strength as it crossed into Izard County and impacted the rural community of Zion, killing two people. Hundreds of cattle were killed in this area; an unanchored home was swept clean from its foundation. Maintaining EF3 intensity, the tornado then struck the town of Highland in Sharp County, resulting in severe damage. To the northeast of Highland, the tornado rapidly weakened and dissipated.
Southaven, Mississippi/Memphis, Tennessee
At 5:32 p.m. CST (2332 UTC), a supercell thunderstorm produced a multiple-vortex tornado in Southaven, Mississippi. The tornado first struck Southaven High School, where 30 windows were broken, minor roof damage occurred, and damage was rated EF0. In the nearby Carriage Hill subdivision, several homes sustained minor damage as well. The tornado rapidly intensified to EF2 strength as it crossed the intersection of Stateline Road and Airways Boulevard, destroying three warehouse buildings. One of the buildings destroyed was the Cooper Lighting Plant, and a gas station in this area was damaged as well. Numerous trees and power poles were also downed in Southaven.
The tornado maintained EF2 intensity as it quickly tracked across the Mississippi – Tennessee state line and into southeastern portions of Memphis, where WREG tower cameras broadcast live footage of the tornado moving through the southeastern parts of Memphis, producing multiple bright blue power flashes along the way. By this point, the National Weather Service issued a Tornado Emergency (the first of five to be issued during the outbreak) for most of the Memphis metropolitan area. The tornado produced an extensive swath of damage as it moved through residential and commercial areas. Considerable damage was reported at Memphis International Airport, where a hangar lost its roof, the FedEx freight terminal's fire station suffered roof damage, airstair trucks were thrown , and aircraft were moved around, including a Boeing 737 that was moved one foot. FedEx service was disrupted due to flight delays and closed roads, all because of the tornado damage in surrounding areas. The airport weather station's reporting equipment recorded a wind gust of . In the Clarke Road area, tractor trailers were tossed around, a power substation was severely damaged, and several warehouse structures sustained heavy damage. This included a DSC warehouse that was destroyed, killing three people inside. Numerous windows were shattered at the Willow Lake Business Park, and utility poles and trees were snapped in the area. Multiple homes along Maple Tree Drive and Pinbranch Court were damaged, five of which sustained major damage. The Hardy Bottling Company facility was also damaged, which released of anhydrous ammonia into the atmosphere, although no public health impacts were reported. Continuing northeast, the tornado weakened to EF1 strength and struck the Hickory Ridge Mall, resulting in total collapse of a large wall and much of the roof at the Sears department store. Damage surveyors noted very poor construction at this location, and six people in the mall were injured. Cars and semi-trailers near the mall were flipped and damaged as well. A Taco Bell and a few other businesses were damaged along Winchester Road before the tornado dissipated. Numerous trees and power poles were snapped along much of the tornado's path through Southaven and Memphis, and electricity supply to about 65,000 customers was briefly cut.