Unseasonable Mega-Killer-Tornado – Climate Change or Not

 

"One word: remarkable; unbelievable would be another… 

It was really a late spring type of setup in the middle of December." 

Victor Gensini, Professor of Meteorology at Northern Illinois University

It was a killer December weekend. The fiercest and longest tornado (227 miles, 200 of which touched down in Kentucky), accompanied by other parallel twisters, leveled entire towns, crushed buildings, tossed cars, sucked animals and even structural steel into its vortex… leaving dozens and dozens of dead, numbers that we will still be counting as we sift through the rubble left behind. A Republican governor and a Democratic President came together as Americans to address the massive pain and suffering. December tornados are exceptionally rare; uniform late autumn/winter cold is not tornado season, and while tornados exist in this part of the United States, this particular rain of powerful twisters was farther east than “normal.”

Experts warned of expected strong tornados before the devastation. Weather services across the area measured the anomalous weather – unusual temperatures in the high 70s (even 80) in what would be the path of that tornado swarm on the other side of a western cold front with temperatures in the 30s, more normal for this time of the year. Cold was about to slam into warm and moist. And when it did, the experts were beyond right. While residents were aware of the danger, which may have saved lives, there was no clear prediction of exactly where tornados would touchdown. There really never is. The above map shows those paths of destruction. The small Kentucky town of Mayfield, pictured above, for all intents and purposes ceased to exist. And that was only a small part of the twister paths.

On December 12th, Suman Naishadham and Seth Borenstein, writing for the Associated Press, surveyed experts on what causes tornados and exactly why this bizarre attack of twisters happened on December 11th: “Tornadoes are whirling, vertical air columns that form from thunderstorms and stretch to the ground. They travel with ferocious speed and lay waste to everything in their path… Thunderstorms occur when denser, drier cold air is pushed over warmer, humid air, conditions scientists call atmospheric instability. As that happens, an updraft is created when the warm air rises. When winds vary in speed or direction at different altitudes - a condition known as wind shear - the updraft will start to spin.

“These changes in winds produce the spin necessary for a tornado. For especially strong tornadoes, changes are needed in both the wind's speed and direction… ‘When considerable variation in wind is found over the lowest few thousand feet of the atmosphere, tornado-producing 'supercell thunderstorms' are possible,’ said Paul Markowski, professor of meteorology at Pennsylvania State University. ‘That's what we had yesterday.’

“There's usually a lot of wind shear in the winter because of the big difference in temperature and air pressure between the equator and the Arctic, Gensini said… But usually, there's not a lot of instability in the winter that's needed for tornadoes because the air isn't as warm and humid, Gensini said. This time there was.” So, this set of killer tornados, punctuated with that 227-mile mega-death twister, happened because of anomalous super-warm temperatures over what became the unfortunate target area. Is that enough to attribute this destruction to climate change? The answer is a big maybe but with a statistical “highly probable.”

“Scientists are still trying to sort out the many conflicting factors about whether human-caused climate change is making tornadoes more common - or even more intense. About 1,200 twisters hit the U.S. each year - though that figure can vary - according to the NOAA National Severe Storms Laboratory. No other country sees as many.

“Attributing a specific storm like [what happen on 12/10-12/11] to the effects of climate change remains very challenging. Less than 10% of severe thunderstorms produce tornadoes, which makes drawing conclusions about climate change and the processes leading up to them tricky, said Harold Brooks, a tornado scientist at the National Severe Storms Laboratory… Some of this is due to La Niña, which generally brings warmer than normal winter temperatures to the Southern U.S. But scientists also expect atypical, warm weather in the winter to become more common as the planet warms….

“Scientists have observed changes taking place to the basic ingredients of a thunderstorm, however, as the planet warms. Gensini says in the aggregate, extreme storms are ‘becoming more common because we have a lot warmer air masses in the cool season that can support these types of severe weather outbreaks.’… The U.S. is likely to see more tornadoes occur in the winter, Brooks said, as national temperatures rise above the long-term average. Fewer events will take place in the summer, he said.” AP.

“Tornado alley” seems to have shifted eastward into the Mississippi/Ohio River Valleys, because of increases in temperature, moisture and shear. But explaining the ferocity of this tornado attack, far beyond anything in recently recorded history, suggests a permanent and growing change in regional climate realities. Normally, a tornado hits the ground and dissipates in minutes, albeit able to leave substantial destruction even for the short time it is on the ground. We really have not seen a sustained touchdown like this since 1925, and scientists believe this December event may actually exceed that record. When you look at all the ingredients that gave rise to this killer event, it’s like a list of the hallmarks of global warming.

I’m Peter Dekom, and as long as this planet is left with leaders that deny or marginalize the impact of climate change (climate “emergency”?), trying to soften the unpleasant truths and remedies to a skeptical public thus delaying what must be done, the more devastating the consequences.