The insured loss estimate from KCC includes damage to residential, commercial and industrial properties
Catastrophe modelling firm KCC estimates that the insured loss from the 9-12 December severe convective storm (SCS) outbreak, which includes the Quad-State Tornado and damaging winds and hail, will be around $3 billion.
This estimate includes the privately insured damage to residential, commercial, and industrial properties and automobiles. There have been thousands of reports of damage and hundreds of reports of destroyed homes and businesses including factories and warehouses.
A combination of above-normal temperatures and anomalous moisture allowed for high amounts of available atmospheric instability to fuel storms. On Friday evening, an intense low-level jet of strong southerly winds was located over Missouri and Kentucky.
At that time, a strong upper-level jet stream maximum with winds out of the west-southwest was moving into the region, producing not only vertical wind shear but also directional wind shear. Once deep convection started to form along a cold front, the storms could easily tap into the high amounts of available vertical wind shear and exhibit rotation.
The most severe supercell developed from a cluster of thunderstorms that initiated out ahead of the cold frontal boundary in Arkansas. Because it formed out ahead of the other convection, the supercell did not have to compete for fuel with other storms.
A favourable environment consisting of warm, moist, and unstable air stretched out ahead of the cell for hundreds of miles across multiple states.
The tornado outbreak caused significant damage, the most significant of which has been reported in Kentucky. In Warren County, which includes Bowling Green, many structures including the TMS Automotive plant were levelled.
Significant damage was also reported in Arkansas, Illinois, and Tennessee. Dozens of buildings, including a large warehouse, were destroyed in Trumann, AR.