Lably
Skip to content

2021 Western Kentucky tornado

Deadly EF4 tornado in Kentucky, United States

  • 25 min read
  • 4 chapters
The December 10, 2021 Western Kentucky tornado as seen near Cayce, Kentucky from Obion County, Tennessee.
Michael Cox / CCTV Camera · Public domain

Related on Lably

Through Tornado

Early estimates suggested the tornado family, which some media outlets described as a "Quad-State tornado" due to the storm's long track and similarity to the 219-mile (352 km) Tri-State tornado of 1925, might have traveled 250 miles (400 km) on the ground, making it the longest-tracked tornado in history. Storm surveys found the majority of the storm's path consisted of two separate EF4 tornadoes, and three weaker, short-lived tornadoes in between them in northwestern Obion County, Tennessee. The parent supercell that produced the two EF4 tornadoes, and eleven tornadoes in total, later became known as the Quad-State supercell.

After the tornado, a state of emergency and a federal disaster were declared by Governor Andy Beshear and President Joe Biden on December 11. The death toll of 57 was the highest from a tornado in the month of December in U.S. history, while also being the deadliest tornado since 2011. Some of the worst damage occurred in Mayfield and was considered by some National Weather Service (NWS) analysts in a case study as bordering on EF5 intensity, prompting discussion on the intensity of high-end tornadoes and damage requirements.

Multiple workers at the Mayfield Consumer Products candle factory that was destroyed with multiple casualties alleged that supervisors told them they would be fired if they left their shifts early ahead of the storm's direct hit on the city. Company spokespeople have denied the allegations. On December 17, it was reported that multiple workers (only one was named due to fear of reprisal) filed a class-action lawsuit against the company. The lawsuit alleged that the company had up to three and a half hours to allow employees to leave before the tornado hit the factory and showed a flagrant indifference to the rights of the workers.

Meteorological synopsis

On December 8, 2021, the NWS Storm Prediction Center (SPC) outlined a slight risk of severe weather across a broad area of the Mississippi Valley. Despite the potential for a higher-end severe threat to materialize, forecasters were uncertain about the extent of instability, degree of directional wind shear, and the timing of potential storms. The following day, the SPC noted an increased potential for organized severe thunderstorms in the region between southeastern Arkansas and southern Indiana, and upgraded that area to an enhanced risk.

As an intense, upper-level trough progressed across the High Plains, with robust instability and moisture return across the Mississippi Valley, the SPC expanded the enhanced risk and introduced a moderate risk area from northeastern Arkansas into southern Illinois on the morning of December 10. Forecasters indicated atmospheric conditions favored the development of nocturnal supercells capable of producing long-tracked, strong tornadoes.

At 3:00 p.m. CST (21:00 UTC), the SPC issued a tornado watch across the highest-risk area: central and eastern Arkansas, west Tennessee, northwestern Mississippi, southeastern Missouri, and southern portions of Illinois and Indiana; it was the first of eleven such warnings issued over the next few hours for the middle Mississippi Valley. Initial storms developed across central Arkansas around 2:00 p.m. CST (20:00 UTC), and weaker activity developed over central Missouri around 90 minutes later. Additional clusters of thunderstorms developed over southwestern Missouri – forming between Bolivar and Carthage, eventually back-building into northeastern Oklahoma – and central Arkansas, forming southwest of Hot Springs, between 5:00 and 5:30 p.m. CST (23:00–23:30 UTC). Though this activity lacked much vigor at its onset due to a strong capping inversion, the convective cells began to show organization as they progressed eastward.

One storm that formed from the initial mid-afternoon activity near Arkadelphia, Arkansas, matured into a long-lived supercell as it progressed in an unstable, deeply moist, and highly sheared environment. This cell persisted for more than 550 miles (890 km) over several hours from eastern Arkansas to northeastern Kentucky, producing eleven tornadoes, two of which were large and intense. The cell started showing signs of surface-based rotation southwest of Searcy, Arkansas, around 5:30 p.m. CST (23:30 UTC). At 5:51 p.m. CST, the National Weather Service office in North Little Rock issued the first tornado warning associated with the storm for portions of Jackson, Lawrence, White, and Woodruff counties. One of the first tornadoes associated with the storm, an EF0, touched down in western Poinsett County near Weiner around 6:40 p.m. CST; about fifteen minutes later, storm spotters reported a large tornado near Greenfield, prompting a particularly dangerous situation (PDS) tornado warning for portions of Poinsett, Craighead, and Mississippi counties, including areas to the south of Jonesboro.

Doppler radar analysis estimated the supercell maintained a nearly continuous, high-end rotational vorticity signature, averaging 94 mph (151 km/h; 82 kn) for approximately four hours and twenty minutes, a rarity among thunderstorms that produce mesocyclonic vorticity (averaging 1.5% of all supercells). The only velocities below the average recorded along the storm track were observed between 8:44 and 9:01 p.m. CST [02:44–3:01 UTC] as the storm crossed from Obion County, Tennessee, into Hickman County, Kentucky. This time frame coincides with the start of the Western Kentucky tornado, implying the supercell underwent a mesocyclone re-strengthening phase during this period. During this intense tornado's lifetime, peak gate-to-gate velocities of 128 mph (206 km/h; 111 kn) were recorded at 9:58 p.m. CST (04:58 UTC) over northeastern Marshall County, Kentucky.

Elsewhere, multiple lines of intense storms, some with embedded supercells, developed across the Mississippi Valley region through the night, and generated other strong, long-lived tornadoes. By the pre-dawn hours of December 11, a decrease in instability led to a gradual weakening of a line of thunderstorms along the associated cold front from eastern Kentucky southward into central Alabama.

The SPC issued a record-setting 43 mesoscale discussions (MCDs) between 12:00 p.m. UTC December 10 and 12:00 p.m. UTC December 11, all of which were associated with the broader storm system. Thirty-eight of these were convective discussions relating to severe thunderstorm activity, and five were non-convective discussions relating to heavy snow associated with the system that concurrently fell across much of the Upper Midwest. Through the night, the National Weather Service (NWS) issued 149 tornado warnings across Arkansas, Tennessee, Missouri, Mississippi, Kentucky, Illinois, and Indiana. These included multiple PDS tornado warnings and tornado emergencies in Arkansas, Tennessee, Kentucky, and Missouri. Eight of the tornado warnings issued by the NWS offices in Memphis, Tennessee, and Paducah, Kentucky, during the event were tornado emergencies, the most ever issued during the month of December, breaking the previous record of three issued on December 23, 2015.

Sign in to keep reading

3 more chapters are free with a Lably account.

More in Earth science