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Two tornados ripped through parts of New Orleans Tuesday, crunching cars, tearing homes off their foundation and leaving at least two people dead in an area of Louisiana devastated by Hurricane Katrina 17 years ago and by Category 4 Ida just last year.
Other deadly tornadoes in the same storm system had hit parts of Texas and Oklahoma on Monday before moving eastward. Texas alone had 20 separate tornadoes.
March does kick off the typical tornado season that runs until June. Still, it’s rare to have a tornado touch down near New Orleans, which is much more accustomed to seeking shelter from hurricanes.
And so the unexpected severe weather raised fresh questions about whether more extremes can be expected, and if global warming and broader climate change is partly to blame.
Scientists don’t have a complete picture connecting climate change and tornadoes. That’s in part because the U.S. is unique in the world by the number of tornadoes recorded. About 1,200 twisters are seen the U.S. each year, according to the NOAA National Severe Storms Laboratory.
For sure, scientific interest was heightened last December, when a miles-long destructive path for a single twister mostly in Kentucky broke a century-old record for distance and surprised many with its winter-time appearance. Warm weather was a factor as tornadoes chewed up parts of at least five states that weekend.
Some scientists say that the atmospheric conditions that give rise to such outbreaks are intensifying in the winter, extending the March-June season as the planet warms.
Studies do show tornadoes getting more frequent, more intense and more likely to come in swarms.
What’s more, “tornado alley” is shifting to states farther east from the Plains states that are notorious for twisters.
Researchers are working to better understand how the building blocks for tornadoes — atmospheric instability and wind shear — will respond to global warming. It is likely that a warmer, more humid world would allow for more frequent instability. However, it is also possible that a warmer world would lessen chances for wind shear.
“ About 1,200 twisters are seen the U.S. each year, according to the NOAA National Severe Storms Laboratory. ”
“The most intense and longest-lasting tornadoes tend to come from what are known as supercells — powerful rotating thunderstorms,” tornado scientist Ernest Agee of Purdue University, says in a commentary for The Conversation. The December cluster of 60 tornadoes that swept across Kentucky and neighboring states came from a supercell. The 2011 outbreak in Alabama was another.
“All of this unfolds under the umbrella of global warming. While it’s still hard for climate models to assess something as small as a tornado, they do project increases in severe weather,” Agee said.
President Biden, who has pushed environmental policies, was asked after December’s deadly tornado if he can link climate change to the devastation. “All I know is that the intensity of the weather across the board has some impacts as a consequence of the warming of the planet and climate change,” Biden said. “The specific impact on these specific storms, I can’t say at this point. I’m going to be asking the EPA and others to take a look at that.”
Less than 10% of severe thunderstorms produce tornadoes, which holds back some scientists from drawing conclusions about climate change, Harold Brooks, a tornado scientist at the National Severe Storms Laboratory, told the Associated Press.
Some scientists do expect atypical, warm weather in the winter and early spring to become more common. The U.N.’s climate panel has warned that global warming of 2°C will be exceeded during the 21st century unless rapid and deep reductions in CO2 and other greenhouse-gas emissions occur in the coming decades, achieving the goals of the 2015 Paris Agreement.
“‘As bad as these new outbreaks are, science and technology are saving lives at a faster rate than storms are killing people.’”
And in addition to loss of life, severe weather is running up a huge bill when it comes to economic loss and insurance payouts. The 10 most expensive climate change-linked disasters of 2021 cost $170 billion.
Hurricane Ida, the Texas power outage, and a deadly Canadian heat wave made last year the sixth time within the past decade that global natural catastrophes have topped $100 billion in insured losses.
The good news is that despite an increase in the number of tornadoes, the per capita death toll has actually gone down in the latter half of the past 100 years, according to Purdue’s Agee. That’s owed to better forecasting technology and better warning systems, although residents with fewer resources and the elderly are often at risk.
“So, as bad as these new outbreaks are, science and technology are saving lives at a faster rate than storms are killing people,” Agee said.
