Analysis of the 2013 Moore Tornado

View of the Moore tornado moments before it impacted Briarwood Elementary School at EF5 intensity. (Video stills by David Demko and Heidi Farrar)

□ The most catastrophic tornado in recent Oklahoma history touched down in the midst of a large scale severe weather outbreak on May 20th, 2013. The tornado devastated southern sections of Moore, a large suburb to the southwest of Oklahoma City. Moore was the focus of international media following a similar F5 tornado that swept through neighborhoods only one mile to the north in May of 1999.

Aerial view of extreme tornado damage in Moore (Santa Fe Avenue is the large street at right). A damage survey later concluded that several homes on SW 147th Street (left center) were swept away in EF5 fashion (Ortega, Burgess et al., 2014). While initially reported as being in excess of two miles wide, the tornado’s primary damage path was approximately 100 to 300 yards in width. (Image by Steve Gooch)

At top left, view of the tornado as it rapidly intensified in Grady County. At bottom left, the tornado became partially rain wrapped as it crossed the Canadian River into Cleveland County. At bottom right, the tornado as it entered Moore. (Video by KWTV)

The tornado touched down at 2:55pm near the town of Bridge Creek, the same community that was nearly wiped off the map following the 1999 Moore tornado. Video of the tornado suggests it initially appeared as a large “stovepipe” before entering a period of rapid intensification, at which point it expanded and became partially shrouded in a column of rain. The swirling mass reached high-end EF4 intensity as it thundered through rural areas east of the Canadian River. Several large homes on SW 155th Street were swept completely away and grass was scoured from the ground as the tornado approached peak intensity just west of Moore. The Wallace Horse Park on Western Avenue was impacted directly by the tornado, killing all but one of the horses being held at the facility (“Oklahoma Officials…”, 2013). The bodies of several horses were recovered a quarter mile away near Sylena Way. Trees along Western Avenue were stripped of bark and branches and left pointing towards the east. The tornado reached the edge of Moore at approximately 3:15pm. Witnesses described the tornado as a “black wall” surrounded by a continuous rain of debris.

Ground scouring and empty foundations near SW 155th Street, a half mile west of Moore. The tornado was likely at EF5 intensity in this area, though building construction only permitted a high-end EF4 rating. The Wallace Horse Park was located at the intersection at top left. (Image by Steve Gooch)

Briarwood Elementary School (bottom) was impacted directly by the tornado as it entered a densely populated section of Moore. The damage to the school was deemed to be of EF5 intensity (NWS, 2013). One woman was killed just east of the school in a home on SW 147th Street. (Image by Steve Gooch)

Extreme home damage in western Moore. (Image by David McNeese)

The tornado entered Moore near the intersection of 149th and Western Avenue, where hundreds of large one and two-story brick homes were obliterated. Briarwood Elementary School was impacted directly by the tornado at EF5 intensity, resulting in the near complete destruction of the school’s classroom buildings and gym. The tornado roared eastward towards Santa Fe Avenue, where at least one fatality occurred in the destruction of a two-story home. After roaring over Penn Lane, the tornado passed directly over Plaza Towers Elementary School at probable EF5 intensity. The large, brick school was nearly leveled while more than 70 students and teachers huddled in the bathrooms. Seven students were crushed to death as the building collapsed – initial reports that the students “drowned” in a puddle or swimming pool were erroneous (Kelly, 2013). Homes just south of the school on SW 14th Street were swept completely away and grass in a nearby field was scoured from the ground. One survivor in the area said the tornado shook the ground like an earthquake and was “louder than anything he had ever heard before” (Lawrence, 2013). While the survey analysis is ongoing, aerial imagery suggests that some of the most intense damage in Moore likely occurred in the vicinity of Plaza Towers Elementary.

Satellite view of the tornado’s devastating path through Moore. The storm caused EF5 damage at Briarwood Elementary and areas to the west. Another patch of EF5 damage occurred at the northern crest of the damage path immediately west of the Moore Medical Center (Ortega, Burgess at al., 2013).

Plaza Towers Elementary School before the tornado. (Image courtesy of Google Earth)

Extreme damage to Plaza Towers Elementary School and homes to the south, which were swept from their foundations. Wind rowing and ground scouring were evident throughout the damage path in Moore. A damage survey concluded that the construction standards in this area only permitted an EF4 rating, though EF5 damage likely would have occurred had a home of “superior construction” been struck.

As the tornado continued on, it curved to the north and momentarily paused just west of Telephone Road. Four people, including a mother and her infant son, were killed after taking shelter in a walk-in freezer at a 7-Eleven convenience store on the northern margin of the damage swath (a similar tragedy occurred at a Pizza Hut in Joplin, Missouri, following an EF5 tornado in 2011). On SW 6th Street, a row of well-built homes was obliterated in EF5 fashion. Across the street, the massive tornado engulfed the Moore Medical Center. The complex was severely damaged and vehicles in the parking lot were mangled beyond recognition and piled against the building’s remaining walls. Due to extensive warning and the strong construction of the building, no fatalities occurred at the medical center. A large movie theater that had been directly in the storm’s path suffered only modest damage as the tornado’s inner core made a brief curve to the north.

The Moore Medical Center was impacted directly by the massive tornado. Dozens of cars in the adjoining parking lot were hurled against the structure’s western wing. Some vehicles nearby were damaged but largely unmoved, an indication the tornado had a violent multiple vortex structure. (Image by Steve Gooch)

At left, a tree stripped completely of bark and branches. At right, extreme damage to the well-constructed Moore Medical Center. (Images by Brett Deering)

Just east of the Moore Medical Center, the tornado crossed the I-35. More than a dozen abandoned vehicles were swept off the freeway, some of which were left in a tangled mass atop the freeway divider. The tornado began to reorganize in this area and the damage path briefly widened and became more erratic in nature. Video footage and aerial imagery indicate that a narrow core of EF4 winds developed as the tornado’s path made a slight turn to the east. Homes within a streak less than 50 yards wide were obliterated as the tornado roared through subdivisions just south of 4th street.

The remains of vehicles on the I-35. (Video still by KWTV)

In eastern Moore, the tornado narrowed and left a streak of extreme damage less than one block wide. A damage survey later concluded that three homes were swept away in EF5 fashion east of the freeway (Ortega, Burgess et al., 2014). Pictured above is damage to homes on East Moore Court. A total of 23 people were killed directly by the tornado. (Image by Steve Gooch)

The 2013 Moore tornado caused more fatalities in Cleveland County than the 1999 Bridge Creek tornado, which killed 11 in Moore and adjacent areas. Due to the severity of the damage, the 2013 tornado was upgraded to an EF5 less than 30 hours after impacting Moore.

In terms of damage intensity, the 2013 Moore tornado was comparable to the 1999 Bridge Creek tornado. Both tornadoes left multiple instances EF5 damage in the city, but the 1999 tornado reached an even greater level of intensity in rural areas to the southwest. Mobile doppler radar was not present to analyze the 2013 tornado but it is undoubtable that velocities in excess of 250mph would have been recorded during the storm’s passage through Moore.

Graphic depicting the tracks of the 1999 and 2013 tornadoes with red denoting areas of surveyed or probable EF5 damage (intensity estimates for the 2013 storm are subjective and may differ slightly from the final NWS report). The Bridge Creek tornado was nearing the end of its intensity maxima when it reached the edge of Moore but continued causing high-end EF4 damage all the way to Midwest City (out of frame at top). The 2013 tornado, by contrast, fluctuated in strength but left an intermittent trail of EF5 damage all the way across the city of Moore. The storm changed direction and narrowed significantly after crossing the I-35 but continued leaving a thin streak of extreme damage until finally weakening outside Moore.

Extreme damage following the 2013 Moore tornado near Westmoor. Due to extensive warning, few of Moore’s residences were above ground in the destroyed homes. The death toll of 23 was remarkably low considering the scope of the devastation. (Image by 1984 Studios)