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Overview
Tornado paths through Southeastern Virginia On the afternoon of August 6, 1993, a staggering total of eighteen tornadoes touched down across southern Virginia. While this event is uncommon in Virginia, it was not rare by global standards. 90% of the world’s recorded tornadoes happen in America, while the remaining 10% happen almost exclusively in western Eurasia and Australia’s semi-arid and moderate climates. Prior to 1993, Virginia only had an average of 6 tornadoes per year, with a total of 263 tornadoes since 1950. The most active day for tornadoes before this event was October 13, 1983, which produced ten tornadoes. With this in mind, it is easy to see how destructive the August event was over 30 years ago. August 6, 1993 started out quietly for Southeastern Virginia, with highs in the mid 70s and partly cloudy skies. However, as a warm front moved north across Richmond and Henrico County and an approaching low pressure center moved in, these clouds disappeared leading to intense warming throughout the day. Unfortunately, the mild temperatures and high humidity levels in place that day were two of the key ingredients that allowed a warm August afternoon to turn into an historical and deadly evening. As pressures fell due to a low center developing along the front over Southwest Virginia, an upper level short-wave (disturbance) approached. Surface winds and winds aloft struggled against each other producing the ideal vertical wind shear needed for tornadic development that afternoon. The first touch down of the day occurred near the town of Kenbridge in Lunenburg County at 12:43 pm. With hardly any precursor thunderstorms or rain, this tornado seemed to come out of nowhere. This tornado began as an F0 but as it crossed into Dinwiddie County it strengthened to a F2 damaging a well-constructed house on route 622, a barn, a house, and some outbuildings on Route 46, as well as the roofs of a briquet plant and a furniture company in Nottoway County. This tornado ran through 4 counties with a path length of 38 miles and a total damage cost of $720,500. The total life of this tornado was 40 minutes. The most devastating tornado of the day first touched down in the independent city of Petersburg at approximately 1:30 pm, not long after the first tornado lifted. This tornado rapidly grew in size and strength as it moved northeast into the historic district of Petersburg. The F4 tornado leveled several well-built, multi-story brick buildings, along with a train station, and a decorative caboose that was ripped from its anchors and thrown 20 feet. The tornado then moved through the Pocahontas Island neighborhood at F3 intensity, heavily damaging or destroying over 80% of the homes. Forty people were injured and over 100 buildings damaged or destroyed in the Petersburg and Pocahontas Island area. From there, the tornado crossed the river into Colonial Heights where it severely damaged a strip mall, a K-Mart, and a waterbed store. By this point the tornado had decreased in size slightly, but remained at an F3 rating which is why the Walmart in this location was almost completely destroyed. The tornado was as wide as the Walmart was long. 198 people were injured due to the intense splattering and damage by debris and three women, 40, 48, and 56 years of age, were killed. When the tornado crossed into Prince George County, it was at F2 intensity and struck a sand and gravel company. The second floor of the company building collapsed, killing a 28 year old employee who had sought shelter there with some coworkers. Several cars and trucks were overturned and conveyor belts were twisted and bent. One employee spotted the tornado and radioed a warning to others which likely saved some lives. Three employees evacuated a small building shortly before it was destroyed. As the tornado moved northeast, it blew roofs off an apartment complex and caused minor damage to an additional 49 homes in Hopewell at an F1 intensity. The tornado exited Hopewell, weakened to an F0, and dissipated in Charles City County. This deadly tornado ran through 3 independent cities and one county with a path length of 12 miles and a total damage cost of $47.5 million. The total ground time for this tornado was 15-20 minutes. The other sixteen tornadoes were all either F1 or F0 and damage to trees, travel trailers, trailer homes, barns, and other smaller buildings was significant. Many homes had trees blown into them, several bridges sustained heavy winds and damage, and several vehicles were overturned or heavily damaged. In total, there were eighteen tornadoes, 256 injuries, four deaths, and total damage cost for this day was $52.5 million. This outbreak was not only uncommon for Virginia, it was very rare that this type of outbreak, sometimes classified as a "family of tornadoes", occurred in mid-summer. The residents of Southeastern Virginia will long remember August 6th, 1993. Rarely has such an outbreak of tornadoes been seen in these areas and never so many at one time. Let this day serve as a reminder that devastating tornadoes can occur in any month of the year at any time of the day and at any location in the country. |
Tornadoes:
Tornado - Petersburg
Track Map Close-up of Tornado Path through Petersburg and surrounding area
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The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:
EF0 Weak 65-85 mph |
EF1 Moderate 86-110 mph |
EF2 Significant 111-135 mph |
EF3 Severe 136-165 mph |
EF4 Extreme 166-200 mph |
EF5 Catastrophic 200+ mph |
Preparedness:
The August 6, 1993 outbreak serves as a reminder that devastating tornadoes can occur in any month of the year at any time of the day and at any location in the country. Although tornadoes are most common in the Central Plains and the southeastern United States, they have been reported in all 50 states.Tornadoes are capable of completely destroying well-made structures, uprooting trees, and hurling objects through the air like deadly missiles. Therefore, it is important that everyone has a tornado preparedness kit and plan.
The first thing to do when a tornado warning is issued for your area is to find shelter. If you can get to a safe, sturdy building, then do so immediately. The best place to be safe if a basement or storm cellar. If you are in a building with no basement, then get to a small interior room on the lowest level. Stay away from windows, doors, and outside walls. Do not get under an overpass or bridge, you are safer in a low, flat location. Use your arms to protect your head and neck.
In order to best prepare for a tornado is to know your area’s tornado risk. In the United States, the Midwest and the Southeast have the greatest risk for tornadoes. Knowing the signs of a tornado is also helpful which includes but is not limited to; a rotating, funnel-shaped cloud, an approaching cloud of debris, or a loud roar similar to that of a freight train. Another way to stay informed is to sign up for your community’s warning system. The Emergency Alert System (EAS) and National Oceanic and Atmospheric Administration (NOAA) Weather Radio also provide emergency alerts. If your community has sirens, then become familiar with the warning tone. Pay attention to weather reports and consider constructing your own safe room that meets FEMA or ICC 500 standards, especially if you live in a location that has many tornadoes per year.
If you, or someone you know, has been a victim of a tornado, please share your story so we can prevent others from becoming a victim. When you write, please note that NWS has permission to use your story and, if possible, let us know the town and state you were in and the year the event took place. Thank you.
Sources: FEMA, https://www.ready.gov/tornadoes & https://www.weather.gov/lwx/events_19930806
Photos:
Damage to Downtown Petersburg (Richmond Times-Dispatch) |
Damage to Southpark Walmart (WRIC-TV) |
Damage to Walmart Parking Lot (WBBT-TV) |
Sources: https://www.weather.gov/lwx/events_1993080 , http://www.historicpetersburg.org/the-1993-tornado-in-petersburg/ , http://trevordickerson.com/2008/04/28/tornado-outbreak-suffolk-devastation-colonial-heights-deja-vu/
Environment:
Synoptic summary.
500mb Geopotential Height 08/06/1993 | Sea Level Pressure (mb) 08/06/1993 | 300mb Relative Humidity (%) 08/06/1993 |
Near-storm environment summary. As seen by the various fields below, this case was not a classic setup for significant tornadoes, especially with regards to instability. Surface Based Convective Available Potential Energy (SBCAPE) values barely approached 1000 J/KG with temperatures (not shown) only in the upper 70s. Despite the relatively low SBCAPE values, the 0-1km shear was in excess of 15kt while the 0-6km shear (not shown) was in excess of 60kt. This high shear was caused by the sharp backing of the winds near the warm front extending across southern Virginia, and the veering and increasing of winds with height.
Surface MSLP/Dewpoint/Winds - 2pm EDT | Surface CAPE (image)/850mb winds (blue) and sfc dwpts | 0-3km Storm Relative Helicity(hatched) and 0-1km bulk shear (barbs) |
GOES-7 Satellite Loops:
GOES-7 Visible Satellite 10am-4pm 8/3/1993 |
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