Last night, tragedy struck in the form of the most devastating tornado in a decade, killing over 70 people in Kentucky and reducing several whole communities to rubble. This was possibly the longest continuous tornado track in recorded history, originating near Jonesboro, AR and crossing portions of Missouri and Tennessee before unleashing its worst damage on a large swath of western Kentucky – an estimated 227 mile path of destruction. Though we will know more about the death toll, EF-rating, and official path length once emergency crews and NWS survey teams fully sift through the wreckage, this was undeniably one of the worst tornado disasters of my lifetime.
Early comparisons for this event all point to the Tri-State Tornado of 1925, the worst tornado in history. That tornado destroyed 164 square miles including several towns, as it rumbled a 219-mile path from southeast Missouri into southern Indiana. A mile wide behemoth traveling up to 70 mph, that tornado stayed on the ground for 3.5 hours and killed 695 people. Modern warnings and F-scale ratings, still a few decades from inception, would have reduced the death toll and helped us truly compare these disasters, but the Tri-State Tornado would no doubt be a monster by today’s standards as well. Below is a preliminary path comparison of these two long-track tornadoes:
If you ask me, there may be an elevated likelihood for a long-track, multi-state tornado to occur in the upper Delta region. For starters, there are a lot of states packed into a relatively small area. But my argument is more tied to the physical geography – the Mississippi River meanders through an extremely flat floodplain where low level air is likely to be humid, either from local standing water or advection from the Gulf of Mexico. This warm, moist air can be occluded by the Ozarks to the west and the Appalachian foothills to the east, enhancing convection from the surface that would be exacerbated in a convective meteorological setup. Last night’s setup featured a particularly strong jet streak, fast-moving dry air at the mid-level of the troposphere that maximized lapse rate values and initiated the severe storms along this orographic boundary.
The National Weather Service was on top of this outbreak, identifying severe weather potential about 5 days in advance, issuing a tornado watch across the domain by 3pm on Friday, and providing tornado warnings a commendable 30-45 minutes ahead of the largest tornado. However, as with most of the deadliest tornadoes, poor warning communication remains a major hurdle for risk mitigation – the most fatalities occurred at a candle factory in Mayfield, KY where night shift workers were “sheltering in place,” largely unaware of danger until the roof caved in. Likewise, another tornado in this outbreak killed several workers at an Amazon fulfillment warehouse in Edwardsville, IL. I hope that these mass casualty incidents inspire a seed change in how emergency notification is carried out in industry, since ignorance is inexcusable with the abundance of warning communication via smartphone. And I hope that the impacted communities can recover, with help, from this historically terrible disaster.
Worldly Observations 