2011 Smithville tornado

The tornado officially formed at 3:42 p.m. CDT 3 miles (4.8 km) west-southwest of Smithville along the Tennessee–Tombigbee Waterway, before quickly strengthening and striking Smithville, causing catastrophic damage. The tornado swept away numerous homes and structures as it moved northeast, following MS 25. Overall, the tornado destroyed 117 structures in Smithville and damaged 50 others. Continuing northeast, the tornado continued across the Alabama state line into Marion County, where it caused damage near Bexar, Shottsville and north of Hamilton. More structures were impacted as the tornado approached and crossed into Franklin County. The tornado then dissipated near the town of Hodges at 4:23 p.m. CDT (21:23 UTC). The damage path was 37.3 miles (60.0 km) long.

Meteorological synopsis

Setup

The environmental conditions leading up to the 2011 Super Outbreak were among the "most conducive to violent tornadoes ever documented". On April 25, a vigorous upper-level shortwave trough moved into the Southern Plains states. Ample instability, low-level moisture, and wind shear all fueled a significant tornado outbreak from Texas to Tennessee; at least 64 tornadoes touched down on this day. An area of low pressure consolidated over Texas on April 26 and traveled east while the aforementioned shortwave trough traversed the Mississippi and Ohio River valleys. Another 50 tornadoes touched down on this day. The multi-day outbreak culminated on April 27 with the most violent day of tornadic activity since the 1974 Super Outbreak. Multiple episodes of tornadic activity ensued with two waves of mesoscale convective systems in the morning hours followed by a widespread outbreak of supercells from Mississippi to North Carolina during the afternoon into the evening.

Tornadic activity on April 27 was precipitated by a 995 mbar (hPa; 29.39 inHg) surface low situated over Kentucky and a deep, negatively tilted (aligned northwest to southeast) trough over Arkansas and Louisiana. A strong southwesterly surface jet intersected these systems at a 60° angle, an ageostrophic flow that led to storm-relative helicity values in excess of 500 m²s⁻²—indicative of extreme wind shear and a very high potential for rotating updrafts within supercells. Ample moisture from the Gulf of Mexico was brought north across the Deep South, leading to daytime high temperatures of 77 to 81 °F (25 to 27 °C) and dewpoints of 66 to 72 °F (19 to 22 °C). Furthermore, convective available potential energy (CAPE) values reached 2,500–3,000 J/kg.

Forecast

On the morning of April 27, a strong cold front with several areas of embedded low pressure extended from the Texas Hill Country northeastward towards the Arklatex and the Ozarks, and later into the lower Ohio Valley. Warm moist air was in place due to strong southerly flow ahead of the front over Mississippi, Alabama, and Tennessee. An upper level disturbance sparked a broad area of showers and thunderstorms as it moved across the frontal boundary on the previous evening. The eastern edge of the line of showers and storms continued to move eastward, in concert with the upper disturbance, reaching the northwest Alabama border around 2:00 a.m. CDT.

This produced the last and most violent round of severe weather, which began around 2:30 p.m. CDT for northern Alabama as supercells began to line up to the southwest of the area. During the early afternoon hours, the potential for destructive tornadoes was highlighted by the Storm Prediction Center's upgrade to a high risk for severe weather around 1:00 p.m. CDT. This prompted a particularly dangerous situation (PDS) tornado watch, which was issued for northern Alabama and portions of southern Tennessee at 1:45 p.m. CDT. The bulletin that accompanied the watch read:

THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF: MUCH OF ALABAMA, NORTHWEST GEORGIA, SOUTHEAST MISSISSIPPI, SOUTHERN MIDDLE TENNESSEE, EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 145 PM UNTIL 1000 PM CDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...
DESTRUCTIVE TORNADOES...LARGE HAIL TO 4 INCHES IN DIAMETER. THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

The potential for tornadoes ramped up from noon through 9:00 p.m. CDT. During this period, much of Mississippi and Alabama experienced numerous supercell thunderstorms that produced violent tornadoes, including four EF5 tornadoes, one being the Smithville tornado. The Smithville supercell itself existed along a thermal boundary in northeastern Mississippi. This was an east–west oriented outflow boundary left behind by the morning squall line. This boundary is also assumed to be the same boundary that the Hackleburg tornado developed on. Conditions were locally enhanced by more easterly surface winds generated along the residual boundary, allowing for a corridor of enhanced tornado potential.

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Tornado summary

Formation and track into Smithville

After producing a long-tracked EF3 tornado that passed near New Wren, the same supercell produced this tornado that began 3 miles (4.8 km) west-southwest of Smithville along the Tennessee–Tombigbee Waterway near the Glover Wilkins Lock at 3:42 pm. CDT (2042 UTC). The funnel itself explicitly touched down at exactly 3:43 pm. CDT (2043 UTC), snapping numerous trees near the Smithville Recreation Area and scouring the ground. As the tornado crossed Davis Road South, it explosively intensified and reached EF5 strength, shredding trees and deeply scouring the ground in a nearby field, leaving a trench that was still visible in aerial photographs taken more than a year later. The tornado began producing intense damage and swept away multiple homes and structures as it moved northeast, following MS 25.

The first fatality from the tornado occurred in this area as a bed and breakfast was destroyed and swept from its foundation, with debris from the structure scattered long distances downwind. Cinder blocks from the structure were broken into small pieces of concrete and strewn throughout a nearby field. A semi-truck was thrown 300 yd (270 m) and destroyed in this area, and an RV was thrown 250 yd (230 m) and partially embedded into the ground nearby. A second semi-truck was completely torn apart, with only its bumper later found hanging from the struts of the Smithville water tower, located 1.4-mile (2.3 km) to the northeast. One brick residence was swept away along this segment of the path as well, and part of its concrete foundation slab was pulled up and slightly dislodged, with extensive ground scouring and debarking of trees noted on the property. The tornado, slightly weakening yet maintaining EF5 intensity, scoured the topsoil to a depth of one foot (30 cm). Some metal storage buildings and 14 mobile homes were obliterated nearby, with metal framing from some of the mobile homes thrown and twisted into pieces.

A Ford Explorer was thrown a 1⁄2-mile (0.80 km) into the top of the Smithville water tower, then bounced off of it, leaving a large dent, and was hurled an additional 1⁄4-mile (400 m) before impacting the ground and eventually coming to rest on the opposite side of the city. From then on, the tornado strengthened even further as it reached its peak intensity, tearing into the town's eastern subdivision as it destroyed several homes and buildings at violent intensity, flooring tiles and sill plates were removed from foundations. The city hall, the post office, four churches, several businesses, the water system, and the police station were all destroyed as the tornado moved through town. Tar and chip pavement was torn from a road in town and rolled into piles, intense ground scouring was noted in several areas, and a 1965 Chevrolet pickup truck was thrown from one residence and never found. Several other vehicles in town were thrown hundreds of yards, torn into multiple pieces, stripped down to their frames, or wrapped around trees as well. Some instances of damage show that many of the vehicles wrapped around trees encountered extreme sub-vortices, with some sections of sheet metal having been wrapped around trees multiple times. The local medical clinic was destroyed as well, with supplies being scattered around the city.

Itawamba County

The large brick E.E. Pickle Funeral Home was reduced to a bare slab as the tornado exited the northeast side of the city, with the debris scattered and wind-rowed into an adjacent wooded area. Extreme debarking of trees was noted in this area, and pieces of vehicles and structures were strewn long distances throughout the woods. The mangled remains of the Ford Explorer that impacted the water tower was found in a ditch at the edge of this wooded area, the SUV being crushed and flattened. Around this area, it's possible that a "secondary core" existed, this is evident by nearby granite tombstones from a cemetery being blown over in the opposite direction of the tornado's passage, with some being broken and thrown. Overall, the tornado destroyed 117 structures in Smithville and damaged 50 others, killing 23 people. From this point on, the tornado began to gradually weaken as it continued through rural areas northeast of town and moved into Itawamba County, where it uprooted numerous trees and power lines and caused roof damage to a house before exiting the county.

Crossing into Alabama, weakening and dissipation

The tornado then continued across the Alabama state line into Marion County, where it caused EF1 damage to outbuildings and mobile homes near Bexar. Continuing northeast, the tornado re-intensified as it struck the rural community of Shottsville at high-end EF3 intensity, where homes and mobile homes were destroyed, hundreds of trees were snapped and debarked, and seven more people were killed. The tornado produced additional high-end EF3 damage as it continued north of Hamilton, where several mobile homes and frame homes were destroyed, including one frame home at the bottom of a ravine that was swept clean from its foundation (though lack of road access prevented close inspection of the home's construction, precluding a potential higher rating at that location; this implies that the tornado had reached violent intensity once again). Several additional homes were damaged and a chicken house was destroyed as the tornado approached Franklin County. The tornado then crossed the county line and weakened to EF2 strength, where it snapped and uprooted numerous large trees, damaged or destroyed several chicken houses, totaled a car, destroyed a mobile home, tore much of the roof off of a two-story house, and caused significant roof damage to several other homes. The tornado finally dissipated near the town of Hodges at 4:23 pm. CDT (2123 UTC), only a few miles away from where another EF5 tornado touched down over an hour earlier. The damage path was 37.3 miles (60.0 km) long and 3⁄4 mile (1.2 km) wide at its widest point. This tornado killed a total of 23 people along its path, and injured 137 other people.

Aftermath

Mississippi's governor Haley Barbour visited Smithville several days after the tornado struck and surveyed the damage. Multiple organizations arrived to offer aid in the town, including the Red Cross.

Internet misinformation

In 2012, a presentation and paper, given at the 26th Conference on Severe Local Storms by Eugene W. McCaul, with the Universities Space Research Association; Kevin R. Knupp, an atmospheric science professor at the University of Alabama; Chris Darden, a meteorologist at the National Weather Service of Huntsville, Alabama; and Kevin Laws, a meteorologist at the National Weather Service of Birmingham, Alabama, stated fictional information about the tornado was being spread online. Specifically, reports that the tornado had ripped a steel drainage pipe several feet out of the ground were proven to have been fabricated and that road crews had dug up the pipe to ensure vehicular safety as the road was previously declared unsafe.