by Suman Naishadham
The buildings were demolished in downtown Mayfield, Ky., on Saturday, Dec. 11, 2021, after a tornado traveled through the region Friday night. The toll from the tornado that killed dozens of people in Kentucky was climbing Saturday, as severe weather ripped through at least five states. Ryan C. Hermens is the Herald-Leader's reporter.
The warm moist air screamed springtime even though the calendar said December. Dozens of people were killed when tornadoes were spawned by a storm front that was guided by a La Nia weather pattern.
December tornadoes are not uncommon. The path length of the tornadoes likely put them in a category of their own. Experts said one of the twisters probably broke a nearly century-old record for how long a tornado stayed on the ground.
Victor Gensini, a meteorology professor at Northern Illinois University, said one word: remarkable. It was a late spring setup in the middle of December.
Climate change is not quite as clear as whether warm weather was a factor in the tornado outbreak.
Understanding how climate change is affecting the number of tornadoes is complicated by the fact that their understanding is still evolving. They say the atmospheric conditions that give rise to such outbreaks are getting worse in the winter as the planet warms. The tornado alley is moving further east away from the Kansas-Oklahoma area and into states where Friday's killers hit.
Here is a look at what we know about Friday's tornado outbreak and the role of climate change in such weather events.
What causes a tornado?
The air columns that form from the storms stretch to the ground. They travel fast and leave a trail of waste.
Scientists call atmospheric instability when warmer, humid air is pushed over dry, cold air. An updraft is created when the warm air rises. The updraft will spin when winds vary in speed or direction.
A wall collapsed on Kenny Sanford as he left his mother-in-law's apartment. Multiple people were killed when tornadoes and severe weather caused damage across several states. The photo was taken by Mark Humphrey.
The spin is needed for a tornado. Changes in the wind's speed and direction are needed for strong tornadoes.
Paul Markowski, professor of meteorology at Pennsylvania State University, said that tornados are possible when there is a lot of variation in wind. "That's what we had yesterday."
Gensini said that 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 north.
Gensini said that the air isn't as warm and humid in the winter so there isn't a lot of instability needed for tornadoes. This time there was.
What conditions led to the storms of this scale?
Some factors will be studied by the meteorology department.
The warm, moist air that helped form storms in the Midwest and South in December was brought on by spring-like temperatures. The warm winter temperatures in the Southern U.S. are due to La Nina, but scientists expect warm weather in the winter as the planet warms.
The worst-case scenario happened. John Gordon, a National Weather Service meteorologist in Louisville, Kentucky, said that warm air was in the cold season.
Strong wind shear appears to have prevented the tornadoes from dissipating. When updrafts lose energy, tornadoes are thought to die off.
Tony Parrott looked through his daughter's damaged apartment unit after the tornado. Several people were killed by tornadoes and severe weather in several states. The photo was taken by Mark Humphrey.
In this case, the tornado lost energy for hours. He said that part of the reason for the long path of Friday's storm was because of that. The record was set by a tornado that hit four states in 1925. Gensini thinks this one will surpass the other one.
You have to have a fast moving storm in order to get a long path. The storm was moving over 50 miles per hour for most of its life. That's not the speed of the winds, but the movement of the storm.
"You're talking about storm motions on the highway," Gensini said.
How related is the climate change to tornadoes?
It is complicated. There are many conflicting factors about whether human-caused climate change is making tornadoes more common or more intense. According to the National Severe Storms Laboratory, about 1,200 twisters hit the U.S. each year. No other country has the same number of people.
It's very difficult to attribute the effects of climate change to a storm. Harold Brooks, a tornado scientist at the National Severe Storms Laboratory, said that drawing conclusions about climate change and the processes leading up to them is difficult because less than 10% of severe storms produce tornadoes.
As the planet warms, scientists have observed changes to the basic ingredients of a thunderstorm. Extreme storms are becoming more common because we have a lot warmer air mass in the cool season that can support these types of storms.
The US is likely to see more tornadoes in the winter as national temperatures rise above the long-term average. There will be fewer events in the summer.
The University of Oklahoma's Furtado said tornado alley has moved eastward into the Mississippi River Valley. The shift is due to increases in temperature, humidity and shear.
The people in the Mississippi River Valley and Ohio River Valley are becoming more vulnerable to more tornadic activity with time.
The Associated Press. All rights belong to the person. This material may not be published, broadcast, rewritten or redistributed.
The tornado outbreak was related to climate change.
The document is copyrighted. Any fair dealing for the purpose of private study or research cannot be reproduced without written permission. The content is not intended to be used for anything other than information purposes.
