I woke up this morning to horrendous news. Numerous fatalities in Kentucky, Tennessee, Arkansas, Illinois and Missouri have been reported. In Kentucky alone, Governor Beshear said in an early morning press conference, We’re going to lose over 50 people, probably closer to somewhere between 70 and 100,” Beshear said. “It’s devastating.” This outbreak of tornadoes highlights three worst-case scenarios that worry me all of the time.
Tornadoes at Night
I am always concerned when I see the threat of nocturnal tornadoes in rural or urban regions. In fact, my family knows that I check conditions before going to bed. If there is a threat of severe weather, I make sure that all of my Wireless Emergency Alerts (WEA) and Weather Apps are functioning. Even still, I find it difficult to sleep. The National Weather Service (NWS) knew something bad was possible in this region. The NWS noted in its Thursday evening discussion, “The main focus continues to be the severe weather potential for Friday night. Shear and instability parameters have become more favorable for rotating storms.” Clearly, the ingredients were in place. The discussion went on to say, “Storms are expected to develop sometime Friday evening along or just ahead of the cold front as it approaches the mid Mississippi Valley. Shear/instability and QPF (quantitative precipitation forecasts) appear to be maximized over western Kentucky during the late evening hours into the overnight hours.” The NWS Storm Prediction Center had also identified this region in its one and two-day enhanced to moderate risk areas, respectively.
The graphic below shows that tornado watches up for the region at the beginning of the evening. The Storm Prediction Center tweeted at 8:01 pm (Dec 10th), “Regional radar update 655 pm CST Fri 12/10/21: includes multiple Tornado Watches (areas within dark red outlines on map) across a broad region. Storms will continue to increase in coverage and intensity through late evening, with tornadoes and hail/wind. https://weather.gov”
Even with warnings, nocturnal tornadoes are always a problem. In March (2021), I wrote an article entitled, “Brush Your Teeth And Check For Tornadoes – A ‘Night Plan’ For Severe Weather Is Essential.” The weather forecast can be perfect, but if people didn’t receive the information, there can be dire consequences. Professor Walker Ashley at Northern Illinois University and colleagues published a paper noting that roughly 27% of tornadoes were nocturnal in their 55-year study, but 40% of tornado fatalities were during the night. Their overall conclusion was that tornadoes between midnight and sunrise were 2.5 times as likely to cause fatalities. Unfortunately, some of the devastation was not just in homes. Early reports suggest that many business or industrial operations, like an Amazon warehouse, were impacted.
Long-tracking and an outbreak
Another worst-case scenario is that there were multiple tornadic supercells, and some of them stayed on the ground for a long period of time. The preliminary report from NOAA (below) on December 11 (2021) suggests a multi-state event with every variety of severe weather including 32 tornadoes. Weather expert and Cornell University atmospheric sciences student Jack Sillin makes a great point. He told me in a message, “Based on radar imagery, this was an extremely long-lived supercell thunderstorm that produced one or more strong tornadoes though NWS survey teams will need to confirm just how strong it got and whether the tornado lifted at any point.” Supercells (storms with rotating updrafts) can certainly travel over long distances, but Sillin goes on to say, “this one remained so strong for so long in mid-December in the middle Mississippi-Ohio valley is notable and unusual.”
The time of year
Fatalities and property damage are tragedies at any time. Let’s state that clearly and unequivocally. However, this type of event during the holiday season is just another dagger in an already difficult year with a record hurricane season and COVID-19. While Sillin notes the unusual nature of one of the supercells, it is important to remember that tornadoes in December are not especially unusual, particularly in the South. Though people often associate tornadoes with the spring season, there is really no “tornado” season. Unlike hurricanes, tornadoes can happen in every single month. Sillin notes, “Anytime the ingredients come together, there is a threat even if the calendar says it’s almost time for Christmas.” There is a map at UStornadoes.com that makes this point clearly.
Rarely do tornadoes “come without warning” these days, but if you didn’t have the information or know what to make of it, it probably would be perceived as such. Here are some questions to ask yourself before going to bed this evening:
- Is there a chance for severe weather tonight in my area?
- Are my WEA, weather radios, or weather alert Apps ready to go?
- Do I fully understand that tornado sirens are NOT intended to alert me inside of a building?
- What’s my plan if I need to act or shelter?
Even with these questions, it is not always black and white. We still have some work to do in communicating or “making actionable” this information for decision makers, businesses, and other institutions.