April 13th, 2020 Tornado Outbreak Review

During the overnight hours of April 12th and into the early morning of April 13th, the 4th largest tornado outbreak on record for SC occurred. In the 4 offices that cover South Carolina, there were 36 tornadoes that touched down that night, including 28 total in South Carolina. Our area (which covers the Midlands of SC and the Central Savannah River Area of GA) saw 8 tornadoes, including 5 EF3's, 2 EF2's, and 1 EF1. Unfortunately, there were 77 injuries and 9 fatalities with the 36 tornadoes. 7 of those injuries and 2 of the fatalities occurred with the EF3 that struck Livingston, SC in our forecast area.

In the mid levels of the atmosphere, a sharp shortwave trough was moving through the Tennessee Valley on April 12th, helping to force everything beneath it. A strong jet streak ahead of the trough set the stage for widespread and strong wind shear.

Looking further down in the atmosphere, a strong low-level jet developed ahead of this by the night of 4/12. This south-southwesterly to southerly flow was beneath west-southwesterly flow in the image above, setting up good directional change between the levels as well.

At the surface, a strong surface low was forced across the Ohio Valley. This quickly moved into the Great Lakes by 4/13, pushing a cold front quickly through the region. Ahead of this, surface winds were out of the southeast. This was key to creating more favorable wind shear for the storms, and pushed more significant moisture into the region.

Looking at shear and instability numbers, they were very impressive, especially for the time of day. The tornadoes occurred in our area between 4am and 7am, which is highly unusual for this area, or really any area of the country. Present for this event, we had 1000-1500 j/kg of surface base CAPE, which is a measure of how unstable the atmosphere is. On top of that, there was plenty of shear. There was 70-80 knots of 0-6km shear to organize the storms, and >500 m2/s2 of 0-1km and 0-3km SRH, which is very anomalous. All of these values were in the 90th percentile of observed values at the Charleston sounding location, further indicating the kind of atmosphere we were dealing with.

The combination of these things created a volatile atmosphere during the early morning hours of April 13th. The cold front forced a squall line to develop along it, and given the high moisture, instability, and wind shear, multiple embedded supercells developed within this line. These tracked across much of the state, producing strong and violent tornadoes along their path.

This map covers the most significant tornadoes to strike our CWA in detail. At one point, had 5 tornadoes on the ground simultaneously! Astoundingly, the majority of these tornadoes were classified as strong (EF2 or EF3), with one tornado in Richland County being rated an EF1. From here, we'll go into detail on each tornado.

• Start Location...5 SE Blythewood in Richland County SC
• End Location...6 WNW Elgin in Richland County SC5 SE Blythewood in Richland County SC
• Date...04/13/2020
• Estimated Time...05:53 AM EDT
• Maximum EF-Scale Rating...EF1
• Estimated Maximum Wind Speed...105 mph
• Maximum Path Width...80.0 yards
• Path Length...4.91 miles

A strong EF-1 tornado began near the intersection of Lee Road and Trowbridge Road. The tornado continued northeast for just under 5 miles. The tornado crossed Hard Scrabble Road, Kelly Mill Road, Langford Road and dissipated near Heins Road. The maximum estimated wind speed associated with the tornado was 105 mph.

Much of the damage along the path of the tornado was tree damage. There were numerous trees that had been snapped, uprooted or suffered damage to branches. There were several homes that suffered minor roof damage to roofing materials, such as shingles, along with damage to soffit and fascia on the exterior of structures. Some of the most extensive tree damage occurred just off Langford Road near the Hunters Run neighborhood. There were also several large trees, both hardwood and softwood, that were snapped and uprooted along Kelly Mill Road near the Crickentree neighborhood. This is across the street from Lake Carolina Elementary Upper Campus. Along Ejw Road, across the street from Lake Carolina Elementary Lower Campus, there were several trees that has fallen across the roadway and been cleared. Additionally, along Ejw Road, there were a few trees either snapped, uprooted or with significant branch damage before the road crossed Round Top Branch. Several trees were uprooted along the entrance to Crickentree on Crickentree Drive.

Start Location...6 NNE Vidette in Burke County GA

End Location...10 ESE Hephzibah in Burke County GA

Date...04/13/2020

Estimated Time...04:53 AM EDT

Maximum EF-Scale Rating...EF2

Estimated Maximum Wind Speed...125 mph

Maximum Path Width...700.0 yards

Path Length...16.94 miles

* Fatalities...0

* Injuries...0

A tornado touched down northeast of Vidette in Burke County, GA near Highway 80. The tornado continued in a general northeastern direction, crossing Quaker Road, US 25, and dissipated near Highway 56 and Collins Road. The tornado produced mainly EF-0 and EF-1 damage along its path, but reached EF-2 intensity in several locations with peak wind speeds of 125 mph. The tornado had a path length of approximately 17 miles with a path width of around 700 yards.

The tornado uprooted or snapped a significant amount of trees along its entire path. Along Highway 80, a former auto service cinder block building had its bay doors blown in, causing the roof to lift off and some of the block walls to collapse. Along Coursey Road, nearly all of the pine trees snapped in a field and a couple of houses had significant roof damage. A couple of pecan groves had significant damage with many pecan trees snapped or uprooted near Quaker Road and Taylor Road. West of Story Mill Road near George Perkins Road, there were an extensive amount of hardwood trees snapped and uprooted, with many of them falling on a home and vehicle. Major damage also occurred at a dairy farm along Highway 25, where metal posts supporting a canopy bent and snapped over a feeding area, a feed shed had its roof torn off and the metal framing bent and several other structures on the property had significant roof damage or total roof loss.

Start Location...5 W Savannah River Site in Aiken County SC

End Location...1 WNW Neeses in Orangeburg County SC

Date...04/13/2020

Estimated Time...05:21 AM EDT

Maximum EF-Scale Rating...EF3

Estimated Maximum Wind Speed...140 mph

Maximum Path Width...800.0 yards

Path Length...38.28 miles

* Fatalities...0

* Injuries...0

A strong, long-track tornado began in the Savannah River Site southeast of Jackson, SC, then moved in a general northeast direction in Aiken County near the Barnwell County border. The tornado crossed into Barnwell County northwest of Williston near Davis Bridge Road. The tornado continued northeast across northern Barnwell County and crossed into Orangeburg County where it passed through Springfield and dissipated on the northwest side of Neeses. The tornado path length was approximately 38.28 miles, and at its widest point was just under 0.5 miles. The tornado rating was an EF-3, with peak wind speeds of 140 mph. Based off of high resolution imagery, radar data (including the height debris was detected), and correspondence with Savannah River Site officials, it has been determined that the tornado became strong within the Savannah River Site boundaries as it moved to the northeast. As the tornado moved out of the Savannah River Site, it produced significant damage near Williston Road and Jaywood Road west of Williston. In this area, significant roof damage and a partial wall collapse to a brick house occurred, with a small cinder block workshop destroyed. The tornado then destroyed a vacant cinder block store building, and removed the roof and some of the walls of a metal auto shop building. Nearby trees were all snapped near the base. A mobile home was shifted about 6-10 feet off its foundation along Cherry Tree Road. Along Tinker Creek Road, the tornado destroyed a brick shed and removed most of the roof off a home, completely destroyed a manufactured home near Charleston Highway, and based on aerial photographs blew down a large swath of trees east of the roadway. The tornado then crossed Charleston Highway, removing a large portion of the roof and collapsing an exterior wall of a business. The tornado continued to snap and uproot countless trees as it crossed Davis Bridge Road, and New Forest Road in northern Barnwell County. The tornado moved into Orangeburg County, uprooting many large trees in the town of Springfield, some of which fell on homes and one on a church. The tornado then crossed the path of the Elko to Livingston to St. Matthews EF-3 tornado in the vicinity of Fire Tower Road and Starwood Drive about 2 to 3 minutes later. Several homes along Fire Tower Road had extensive roof and front porch damage. Multiple trees were down along Ninety Six Road, with one of them falling on a house. The tornado finally dissipated east of Ninety Six Road just before reaching the Neeses town limits.

Start Location...4 ENE Savannah River Site in Barnwell County SC

End Location...3 SW Elko in Barnwell County SC

Date...04/13/2020

Estimated Time...05:33 AM EDT

Maximum EF-Scale Rating...EF3

Estimated Maximum Wind Speed...138 mph

Maximum Path Width...50.0 yards

Path Length...8.55 miles

* Fatalities...0

* Injuries...0

Sentinel Satellite Data from April 13, 2020 clearly shows a damage scar beginning at the western edge of Parr Pond in the Savannah River Site and ending near the intersection of Highway 278 and State Road 21. A tornadic debris signature detected by the KCAE radar aligns with the damage scar. A ground survey also indicated a few trees down just off a field on the eastern side of Fellowship Road as tornado dissipated. Based off of high resolution imagery, radar data (including the height debris was detected), and correspondence with a Savannah River Site official, it is estimated that winds reached EF-3 strength, with speeds up to 138 mph.

This tornado was surveyed in a unique way, using satellite and radar data (along with some ground reports) to help survey the damage. One of the factors that played into this being rated as an EF3 was the intensity of the CC minima that the radar picked up on. Research has shown that there is a correlation between  the height of the atmosphere that the CC min reaches and the strength of the tornado .

Start Location...4 S Elko in Barnwell County SC

End Location...8 WSW St. Matthews in Calhoun County SC

Date...04/13/2020

Estimated Time...05:43 AM EDT

Maximum EF-Scale Rating...EF3

Estimated Maximum Wind Speed...140 mph

Maximum Path Width...770.0 yards

Path Length...36.9 miles

* Fatalities...2

* Injuries...7

A strong, long-track tornado began just south of the town of Elko in Barnwell County, then moved in a general northeast direction through Orangeburg County, before dissipating southwest of St. Matthews in Calhoun County before reaching I-26. The tornado path length was about 37 miles, and at its widest point was just under 0.5 miles. The tornado was rated an EF-3, with peak wind speeds of 140 mph. There were 2 confirmed fatalities with at least 7 injured.

The tornado began near Orchard Road and Highway 37. Along its entire path, there was widespread tree damage. The tornado snapped 7 wood power poles near US 78 and Turkey Creek. The tornado strengthened as it approached Highway 3 and Gardenia Road, where it destroyed and tossed a wood framed home anchored to the ground, lifted a significant portion of a roof on a brick home, destroyed a fifth wheel camper, and knocked over a pivot irrigation system. The tornado then crossed Norway Road where it snapped multiple power poles. As the tornado reached Fire Tower Road west of Neeses, it intensified further, destroying 3 anchored manufactured homes on Preserver Road near Ninety Six Road It was in this area that the 2 known fatalities occurred to residents in a double-wide manufactured home. The tornado then turned more eastward, crossing Savannah Highway and Dragstrip Rd north of Livingston. There were several homes or manufactured homes that were heavily damaged or destroyed in this area. The tornado gradually weakened as it crossed North Road and dissipated as it crossed into Calhoun County.

• Start Location...3 S Blackville in Barnwell County SC
• End Location...2 S Blackville in Barnwell County SC
• Date...04/13/2020
• Estimated Time...05:49 AM EDT
• Maximum EF-Scale Rating...EF3
• Estimated Maximum Wind Speed...140 mph
• Maximum Path Width...40.0 yards
• Path Length...1.38 miles

Fatalities...0

Injuries...0

A tornado started just south of Blackville, SC east of Whitehall Drive near Toby Creek. The tornado damaged several chicken houses by causing the walls to collapse in a few places. The tornado then moved northeast crossing a large empty field, before intensifying as it approached a fiberglass coating facility near Lake Cynthia Road. The tornado collapsed a large segment of a 75 ft tall, 150 ft x 150 ft warehouse, with large steel support beams twisted. 30 cylindrical containers weighing up to 20- 25 thousand pounds each lifted out of their u-shaped saddles and rolled throughout the facility. There was evidence of very minimal tree damage east of Blackville but not enough damage to suggest the tornado track continued that far north. As a result, the tornado likely lifted prior to reaching Highway 3. The tornado path length was just under 1.5 miles and had a width of about 40 yards. The tornado was rated EF-3, with peak winds of 140 mph.

Start Location...5 S Hilda in Barnwell County SC

End Location...1 E Hilda in Barnwell County SC

Date...04/13/2020 Estimated Time...05:50 AM EDT

Maximum EF-Scale Rating...EF3

Estimated Maximum Wind Speed...145 mph

Maximum Path Width...800.0 yards

Path Length...5.45 miles

* Fatalities...0

* Injuries...0

A tornado touched down in far southeast Barnwell moving northeastward toward the Bamberg county line southeast of the town of Hilda, briefly intensifying to a strong tornado along Hartzog Road. The tornado length was 5.5 miles and had a width of 800 yards at its widest point. The tornado was rated EF-3, with peak winds of 145 mph. The tornado began just north of Highway 64 at Green Branch Road near Indigo Road. The tornado moved northeast across Hercules Creek and caused significant tree damage at a residence on Friendship Road. Several oak and pine trees were uprooted and snapped. A cinder block garage had its metal roofing peeled off and the wind stress shifted the cinder blocks about half way up the wall. Along its northeastward path, there was continued tree damage but the tornado strengthened rapidly as it crossed Hartzog Road just south of November Road. A well built bolted down metal building structure and tin tractor shed was completely destroyed. Further north along Hartzog Road, a residence had part of its roof lifted off and behind the residence, a two story wood frame building was shifted off its foundation and destroyed and an unanchored log cabin was destroyed. As the tornado moved northeast toward Huckleberry Bay Road there were multiple hardwood trees snapped near the base of the trees. The tornado began to weaken as it crossed Old Salem Road continuing to damage trees along its path before dissipating just north of Huttos Chapel Road.

Start Location...3 NE Rowesville in Orangeburg County SC

End Location...4 SE Cameron in Calhoun County SC

Date...04/13/2020

Estimated Time...06:25 AM EDT

Maximum EF-Scale Rating...EF2

Estimated Maximum Wind Speed...119 mph

Maximum Path Width...700.0 yards

Path Length...10.29 miles

* Fatalities...0

* Injuries...0

A tornado touched down in Orangeburg County about 4 miles northeast of Rowesville and tracked northeastward across Interstate 26 and Highway 301. EF0 damage occurred from the intersection of Garland and Bethel Forest Road, where the tornado started, to just prior to crossing I-26. The tornado strengthened producing EF-1 damage across agricultural fields and in the Orangeburg Industrial Park. As the tornado crossed I-26 it further strengthened to EF-2 then crossed Highway 301. The tornado rapidly weakened to EF-1 then just north of Highway 301 and further to EF-0 as it moved into the Middle Pen Swamp. Through the remainder of the tornado path it cycled between EF-1 and EF-0 then finally lifted just north of the intersection of Houcks Gin Road and Old State Road. The total tornado path length was 10.3 miles with a maximum width of 700 yards.The tornado caused numerous hardwood and softwood trees to be snapped along the path and overturned multiple pivot irrigation systems. Damage was done to a tractor dealership with the front windows being shattered and the overhead doors being blown in by the wind. Several of the snapped and uprooted trees were blown onto structures causing roof damage to residential and industrial structures. Damage to grain silos and outbuildings on the north side of Highway 301 was estimated by the owner to be $1 million.