Was the Tuscaloosa Tornado an EF5? Examining Aerial Damage Photographs

Image of the Tuscaloosa tornado as it roars towards the Rosedale community. Seven people were killed in two apartment complexes and a home adjacent to the videographer. (Video by Ever Duarte)

□ The tornado that left a streak of devastation through Tuscaloosa and the suburbs of Birmingham during the 2011 Super Outbreak has become one of the most well-known tornadoes in history. It became, at the time, the costliest single tornado on record, and easily the most photographed tornado to date.

The National Weather Service took particular care in selecting a rating for the Tuscaloosa tornado. There was tremendous public pressure for an EF5 rating, and surveyors spent more than a week analyzing and reanalyzing the damage path. The area of particular interest was the Tuscaloosa suburb of Alberta City, where the most intense damage occurred. There was much disagreement, and one survey team awarded the damage an EF5 rating, but the NWS eventually classified the tornado as a “high-end” EF4.

Many people were surprised at the decision. The tornado most certainly would have received an F5 rating on the old Fujita Scale, but the new Enhanced Fujita scale has different and somewhat more stringent rating standards. It is important to note the differences between the Fujita Scale and the Enhanced Fujita Scale, as the Tuscaloosa tornado likely lies squarely in between the two categories.

Below are aerial damage photographs that follow the tornado’s path of destruction from Tuscaloosa to suburban Birmingham. Particular attention is paid to areas where EF5 damage may have occurred.

Click on each photo to enlarge.

As the tornado entered the heavily urbanized southwest side of Tuscaloosa, it devastated two large apartment complexes and caused seven fatalities. A dozen buildings were leveled at the Rosedale Community (bottom left), and a section of the Charleston Square Apartments (top right) was flattened, hurling two college students to their deaths. Perhaps the most impressive footage of the tornado was captured by Ever Duarte from an apartment immediately out-of-frame at top center.

A high concentration of fatalities occurred in the Cedar Crest neighborhood, where large, well-built homes were completely flattened. Forest Lake (visible to the left) may have provided the tornado a brief respite from ground friction.

Hurricane force inflow winds shattered windows and uprooted trees four blocks away from the EF4 damage swath. The storm’s massive appearance on video was largely due to the low cloud bases typical of supercells in the Deep South. Compared to most violent tornadoes on April 27th, the tornado was quite narrow as it passed through Tuscaloosa – all of the worst damage was confined within a 150-yard wide streak. After exiting town, the tornado widened considerably.

The tornado strengthened as it crossed University Boulevard into the suburb of Alberta City. An apartment complex was completely leveled and a large food store (lower right) was swept completely away. There were multiple fatalities in a home just north of the store. Damage in this area was extreme, and an F5 rating on the Fujita Scale was likely appropriate. On the Enhanced Fujita Scale, damage in this area was borderline (but not clearly) EF5 in intensity.

Wider view of the damage around 25th Street. Large, multi-story buildings were obliterated and grass was partially scoured from the ground. The Tuscaloosa tornado was very fast moving and caused most of its damage in less than five seconds.


Video of the tornado from 2406 University Boulevard. The swath of possible EF5 damage passed less than a block east of this location.

Close aerial view of the devastated school near University Blvd. The grass scouring within the streak of worst damage is consistent with a tornado of EF5 intensity, but the damage to the flattened school was deemed to be of high-end EF4 intensity due to the presence of undamaged light poles just south of the main building. (Image by Tim Marshall)

Close aerial view of the devastated Alberta Elementary School. The grass scouring within the streak of worst damage is indicative of extreme intensity. Upon reviewing the damaged school, Tim Marshall awarded an EF4 rating as he found that there were “no ties between the walls and the foundation” (AMS, 2011). (Image by Tim Marshall)

View of the Tuscaloosa tornado over Alberta City. The tornado was likely near maximum intensity at this time. (BamaUAMS)

The tornado was near peak intensity as it passed over the Chastain Manor Apartments, where two residents died. A survey team headed by the National Science Foundation considered the damage to the newly built apartment complex to be of EF5 intensity (LaDue, Marshall, 2011). Two additional survey teams, however, considered it to be “high-end” EF4 damage. The southern building’s second floor, which was at ground level on the uphill side of the complex, was swept cleanly away to its cement floor. The structural anchorage was to code, but not considered “superior” in quality.

One of the UA survey members standing above the remains of a bathroom in the Chastain Manor Apartments. The plumbing fixtures were ripped from the floor, one of the damage indicators that led this particular team to award an EF5 rating. (Songer, 2011)

Close aerial view of possible EF5 damage to the Chastain Manor Apartments. A small but well-constructed club house, just out of frame at bottom, was also swept completely away. Grass around the complex was damaged, but not completely scoured. Considering the speed and size of the tornado, the damage to the apartments likely occurred in only a few moments by instantaneous gusts in excess of 200mph.

After devastating the Chastain Manor Apartments, the tornado tore through a neighborhood along County Road 45. There were multiple fatalities on Crescent Lane as homes were swept from their foundations.

Boats from a business along Keene Street were turned into large projectiles as the tornado struck homes on 5th Street NE. Two homes at bottom center appear to have been swept completely away. The Enhanced Fujita Scale requires that a home of “superior construction” be swept cleanly away for an EF5 rating to be applied. The homes in this area are typical of most frame homes and therefore not adequate to gauge EF5 intensity. The tornado was expanding as it passed through this area and the core of intense damage widened to over a quarter mile in width.

The home at bottom right was likely the one mentioned in the NWS survey as having been swept completely away near Holt Peterson Drive. The house was obliterated in EF5 fashion, but tree damage nearby was not consistent with winds of EF5 intensity. The tornado was a mile wide as it passed through this area. Due to the mountainous terrain, the damage pattern became complex and erratic. Less than a mile northeast of this area, the tornado destroyed a railroad bridge and hurled a 34 ton steel support-truss 100ft uphill.

After exiting the Tuscaloosa metropolitan area, the tornado plowed through 35 miles of unpopulated forestland. Aerial imagery of tree damage suggests that the tornado maintained EF4+ intensity and widened to over a mile in width. Very few tornadoes maintain peak intensity for more than a few miles, nevertheless for

After exiting the Tuscaloosa metropolitan area, the tornado plowed through 35 miles of unpopulated forestland. Aerial imagery of tree damage suggests that the tornado maintained EF4+ intensity and widened to over a mile in width. The tornado, along with several others in the 2011 Super Outbreak, left one of the largest swaths of violent tornado damage ever documented.

After ripping through miles of sparsely populated forestland, the tornado encountered a coalyard rail depot, overturning all but two of the heavy cars. One car, which weighed 36 tons, was hurled 120 yards (visible at center). Eyewtiness statements suggest the car was thrown in one toss as opposed to being rolled. This is the longest distance a railroad car has ever been move, and possible evidence of EF5 winds, as well as an extremely powerful updraft (Knupp et al., 2012)

The tornado encountered a coalyard rail depot just southwest of Pleasant Grove, overturning all but two of the heavy cars. One car, which weighed 36 tons, was hurled 120 yards (visible at center). Eyewtiness statements suggest the car was thrown in one toss and not rolled (Knupp et al., 2012). This is the longest distance a railroad car has ever been moved by a tornado and possible evidence of EF5 winds. Damage in the suburbs of Birmingham also reached borderline EF5 intensity, particularly in a narrow swath of devastation through Concord.

The Birmingham suburbs of Concord and Pleasant Grove both experienced borderline EF5 damage. Well-constructed homes were swept completely away and groves of large hardwood trees were almost completely debarked.

The Birmingham suburbs of Concord and Pleasant Grove both experienced borderline EF5 damage. Well-constructed homes were ripped from their foundations and large hardwood trees were almost completely debarked.

Had the Tuscaloosa tornado occurred back in the 90’s, it would have achieved an F5 rating. The EF-Scale, however, has stricter guidelines that differ from the Fujita Scale. People often erroneously believe EF5 tornadoes are weaker than F5 tornadoes since the former’s estimated wind range begins at 200mph and the latter commences at 261mph. The wind ranges are simply estimates and cannot be taken at face value. The EF-Scale was developed under the assumption that the Fujita Scale overestimated tornadic wind speeds.

All things considered, the tornado likely falls in an unusual place – above the threshold of an F5 but just below the threshold of an EF5. Damage in Alberta City, however, was more impressive than the worst damage caused by some official EF5s, such as the Greensburg, Kansas, tornado of 2007. One inherent limitation with tornado damage scales is the lack of emphasis on wind duration – a variable which, with the addition of multiple vortices and transient wind features, is nearly impossible to calculate. Considering the small size and fast movement of the Tuscaloosa tornado, it is quite likely the tornado had winds significantly higher than other large and more slow-moving EF5 tornadoes. The four tornadoes that were awarded EF5 ratings during the 2011 Super Outbreak, however, were unusually powerful and caused noticeably more intense damage than the Tuscaloosa event, so an EF4 rating may have seemed most appropriate in context.


Above is one of the few videos taken within close proximity of the tornado in Alberta City. The Chastain Manors Apartment Complex was located only a quarter mile south of the videographer’s home.

Incredible Aerial Damage Pictures from the EF5 Smithville Tornado – April 27, 2011

View of the Smithville tornado at maximum intensity. The tornado is directly over town, in the vicinity of Court Street. (surveyormike1 / Youtube)

□  On April 27, 2011, the small town of Smithville, Mississippi, was devastated by one of the most violent tornadoes ever surveyed. Below is a compilation of aerial photographs detailing the first four miles of the EF5 tornado’s damage path. The tornado continued for an additional 34 miles and caused more deaths in Alabama, but the remainder of the tornado’s path was primarily over unpopulated marshland and of lesser intensity. Satellite images of tree damage indicate that the tornado reached maximum intensity soon after touching down and likely weakened not long after exiting Smithville. The NWS report lists 23 fatalities for the tornado’s entire path. With 17 fatalities confirmed in Monroe County and seven deaths reported in Alabama, a death toll of 24 appears accurate.

Click each photo to enlarge.

The visible touchdown point of the Smithville tornado was just east of the Tennessee-Tombigbee waterway. The tornado immediately exhibited a narrow core of intense winds (less than 10 yards wide at some points) imbedded within a larger damage swath. The tornado intensified extremely rapidly and was likely powerful enough to level a home within seconds of touchdown.

 

The tornado reorganized two miles southwest of Smithville and briefly left a trail of intermittent damage with several distinct damage swaths. A narrow, intense vortex abruptly developed at the edge of a wooded area (seen just left of center) and continued all the way through Smithville. Within seconds, the narrow wind feature was powerful enough to leave deep scouring marks in a field. This is an indication of EXTREME intensity.

Close up view of deep ground scouring. Up to 12-inches of topsoil was removed. Scouring patterns were of continuous but varying severity for the next two miles.

A gas station that had been converted into an apartment building was swept cleanly away, leading to the tornado’s first fatality. Three unoccupied mobile homes nearby were obliterated. A large freight rig that had been parked in the apartment’s dirt driveway was torn apart and hurled approximately 200 yards to the northeast (the NWS page incorrectly estimates the rig was thrown 1/4 to half a mile). Vehicles throughout the tornado’s path were thrown long distances, many more than half a mile.

The Smithville tornado paralleled Highway 25 (soon to be called Main Street) and directly encountered its first well-constructed home 1.5 miles after touchdown. The home was swept away in EF5 fashion and grass was scoured from the ground. The EF5 damage path was about 30 yards wide. Lighter damage occurred over a larger area approximately a quarter mile in width.

Closer view of the brick home devastated by the rapidly intensifying tornado on Highway 25. The owner of the home, Mr. Jessie Cox, was among the tornado’s victims. Grass around the home was scoured from the ground, leaving behind a muddy aftermath common to intense EF5 tornadoes. (Thomas Wells)

Wind damage was far more expansive to the south of the tornado’s center. This was the result of the tornado’s rapid forward speed, which added significant momentum to the storm’s right half. The narrow path of the tornado’s inner core is marked by the scoured grass to the north of Main Street (upper left corner). Six more people were killed in homes that were swept completely away along Highway 25. A survey team later concluded that “in the core of the tornado, you had to be underground or in a safe room to survive” (Hayes, 2011).

Two views of the damage track through Smithville. The streak of EF5 damage was narrow and clearly defined, but the visible funnel expanded beyond the town’s two water towers. A truck parked at a residence near Young Street (the close foreground in the right image) was thrown so far that it remained missing at the time of the damage survey (NWS, 2011). (Right side image by JJ Jasper)

Moving at 70mph, the tornado took only seconds to sweep two large, well-constructed brick homes from their foundations. Nearby, a grove of large hardwood trees was obliterated. The intense inner core shifted away from Main Street and raced into a neighborhood north of Smithville's business district. The EF5 damage was confined to a narrow corridor, but moderate to severe damage spread several blocks to the south. Extensive wind rowing is evident - a damage feature unique to the most violent of tornadoes.

Moving at 70mph, the tornado took only seconds to sweep two large, well-constructed brick homes from their foundations. Nearby, a grove of large hardwood trees was obliterated. The intense inner core shifted away from Main Street and raced into a neighborhood north of Smithville’s business district. The EF5 damage was confined to a narrow corridor, but moderate to severe damage spread several blocks to the south. Extensive wind rowing is evident – a damage feature unique to the most violent of tornadoes.

Close view of a destroyed brick home visible in the previous image. The body of the home owner was found in a field to the northeast. Small shrubs and vegetation near the foundation were shredded and pulled from the ground, an indication of intense tornado-ground interaction. Most other E/F5 tornadoes that have caused similar damage, such as the Bridge Creek storm of 1999, were larger and significantly slower moving than the Smithville tornado. One town resident, who witnessed the tornado from the Smithville Telephone Company, described the tornado as a “black swirling mass” that “moved so fast it was unbelievable.”

A red SUV was hurled a half mile through the air before impacting the top of the 130ft Smithville water tower, leaving a visible dent. The vehicle was then thrown an additional quarter mile before coming to rest near the foundation of an obliterated funeral home at the end of Cemetery Drive.

A red SUV was hurled a half mile through the air before impacting the top of the 130ft Smithville water tower, leaving a visible dent. The vehicle was then thrown an additional quarter mile before coming to rest at the end of Cemetery Drive. Photographs indicate the SUV was crushed into a ball only a few feet across.

Wide view of the tornado’s path through the northern section of town. The streak of EF5 damage was imbedded within the tornado, which enveloped nearly all of the buildings visible above. There were 16 fatalities in Smithville, a remarkably low figure in relation to the number of buildings that experienced EF5 damage. The low death toll is attributed to the fact that the tornado struck in the middle of a workday when many of the homes were vacant.

Multiple instances of EF5 damage between Monroe and Maple Street. Survivors reported that the fast moving tornado lasted less than ten seconds. Pronounced ground scouring is visible within the center of the damage track. Most of the giant hardwood trees that decorated the area were snapped just above ground level. A section of missing road can be seen on Market Street (at left center) near the railroad tracks. While initially reported as tornado damage, a later report indicated the road was purposefully demolished in order to deter traffic over the damaged culvert (Knupp and Laws, 2012).

Close aerial view of the narrow streak of extreme destruction near Market Street. The tornado passed through the “nicest section of town”. Two brick homes once shared a backyard to the left of the large tree trunk at center. Calculating the tornado’s forward speed and the width of the EF4+ damage track indicates peak winds lasted less than three seconds. (Thomas Wells)

The businesses along Main Street suffered severe damage despite being outside the tornado’s inner core. A Piggly Wiggly supermarket (large building at bottom center) was gutted by violent inflow winds. Farther north, a cluster of mobile homes was swept away in the core damage path, causing one death. The twisted frames of several mobile homes were thrown a half mile and found wrapped around debarked trees to the east of Cemetery Drive. Fortunately, it appears that, with the exception of the single fatality, none of the other residents on the block were home at the time.

Close view of buildings along Main Street. A large, two-story brick column post office (bottom left) collapsed with several people inside, all of whom survived. A neighboring business to the north was reduced to a concrete slab. Surveillance cameras at the Smithville police station (bottom right) captured the only known footage of the tornado from within town. One survivor on Main Street described the tornado as a quick “blast of air” from the southwest, like “a nuclear shock wave”, that flattened all of the buildings at once.

Three large, well-constructed homes with extensive foundation anchoring were reduced to bare slabs. Surface vegetation was scoured from the ground.

Two views of catastrophic home damage. The image at right shows the complete destruction of several large homes on Elm Street. A two story brick home (center right) was swept so completely away that even the sill plates appear to have been pulled from the foundation. At left are the remains of two well-constructed homes (visible in the previous photograph) before any clean-up had commenced. Grass scouring is evident near the foundations. (Thomas Wells)

Wide aerial view of the swath of EF5 damage. Seven additional fatalities occurred east of the railroad tracks between Earl Frye Street and Cemetery Drive. There were no survivors in the three obliterated homes on Monroe Street (visible at left center). Before the tornado struck, the city built an extension of Monroe Street using gravel and tar in order to build new houses (visible at bottom center). The tornado blew the exposed tar (not pavement) from the street, leaving bare soil underneath.

South facing view of homes along Elm Street and Poplar Street before the tornado. The section of Market Street that was later torn from the ground is visible at extreme lower right. Most of the residences in the area were old one and two-story homes, some of which were well anchored to their foundations. (Bing Maps)

South facing view of homes along Elm Street and Poplar Street before the tornado. Most of the residences in the area were old one and two-story homes, some of which were well anchored to their foundations. (Bing Maps)

Map of the tornado's path through town in relation to the location of fatalities, marked by red dots.

Map of the tornado’s path through town and the location of each fatality (there were two homes where two fatalities occurred – both marked by connected dots). The swath of EF5 damage is highlighted in light orange. Only one death occurred outside the narrow zone of extreme damage – a young women was killed in a trailer on the south side of Highway 25.

A large funeral home was swept cleanly away as the tornado exited town and entered a forested area. The building was empty when the tornado struck, preventing the death toll from climbing even higher. Pulverized vehicles, utility poles, and debris from across town were left strewn among the debarked trees.

A wide view of damage on the east side of Smithville. The tornado’s complex wind distribution is visible through the damage patterns in the forest. Several large, re-inforced brick buildings (bottom center) experienced EF3 and EF4 damage well outside of the worst affected areas. The Smithville Baptist Church was nearly leveled by a rush of westerly winds that hurled cars into the building’s few remaining walls.

Close aerial view of the tornado’s path as it crossed Cemetery Drive. Grass scouring marked the narrow path of extreme winds. Smithville experienced the most intense tornado damage of all the populated areas affected during the 2011 Super Outbreak. (Thomas Wells)

The tornado may have weakened slightly as it passed north of Smithville High School, but winds likely remained in the EF5 range for several additional miles. In the area above, the tornado debarked and flattened a narrow section of pine forest. Southern pines are extremely flexible and durable, but they were no match for winds over 250mph.

*A special thank you to Smithville resident Darnell Collums for her assistance.

(Any Monroe County residents or others who directly experienced the EF5 tornado or its aftermath are asked to contact me at extremeplanetmax@gmail.com.)