Tornadoes aren’t unheard of in California, but they are less common compared to other parts of the country, with fewer than 10 typically observed in the state per year, according to the National Oceanic and Atmospheric Administration. Wednesday’s tornado — which affected the town of Montebello and damaged 17 buildings — was also especially strong, and is the most severe to affect the region in 40 years, per the National Weather Service.
The tornado followed another weaker tornado, which touched down Tuesday in Carpinteria, a town northwest of Los Angeles, and months of other extreme weather in the state.
As Vox’s Benji Jones reported, California has experienced what’s known as “weather whiplash” throughout this year, as it’s endured days of intense rain and flooding after dealing with a severe drought. That rain was the product of a phenomenon called “atmospheric rivers,” what Jones describes as “narrow corridors of water in the sky,” which appear to be happening more frequently this year and causing severe damage.
There’s likely a connection between the storms that California has experienced and this week’s tornadoes. The atmospheric rivers and the rain they brought probably helped lead to increased moisture in the air, which enabled the recent tornadoes to form in the region, says Perry Samson, a professor of atmospheric science at the University of Michigan. “You’ve got the conditions for instability set up by these atmospheric rivers,” Samson told Vox.
The increased intensity of atmospheric rivers may also have links to climate change, many climate experts say. It’s too early to draw conclusions about the relationship between climate change and the tornadoes, however. “You can’t tie it to climate change, because it’s a one-off thing,” says Jase Bernhardt, a professor of geology, environment, and sustainability at Hofstra University.
What is more established, though, is that it’s unusual for the Los Angeles area to experience this type of weather phenomena at this magnitude. “This is stuff you see in Ohio, Arkansas … Not Montebello,” one witness said, according to CNN.
The tornado occurred amid the rise of extreme weather
There have been growing instances of extreme weather worldwide over the last few decades, with a 2020 United Nations report noting a huge uptick in major natural disasters from 2000 to 2019, compared to previous decades. That report attributed a surge in instances of flooding and storms to global warming.
While climate change’s relationship to these tornadoes is uncertain, what is evident is that thunderstorms and tornadoes of this magnitude are uncommon in this region, and that this week’s events were a product of the right conditions being in place. Those include warmer, humid air near the ground and drier, cold air higher in the atmosphere. The warmer air contributing to recent extreme weather could also become more common as global warming worsens, as could storms. Climate change leads to warmer air, and “warmer air can hold more moisture,” which can mean more precipitation, per the New York Times.
“The Carpinteria and Montebello tornadoes formed after recent storms pushed cold air high into the atmosphere, causing it to destabilize. That created thunderstorm cells, which then began to rotate and ultimately become tornadoes,” the Los Angeles Times reports. That combination doesn’t happen very often in Los Angeles due to its topography, says Samson.
Both tornadoes caused notable property damage, with the Montebello one ripping a roof off a building and leading to one minor injury, and the Carpenteria one affecting 25 mobile homes.
The tornadoes follow a tumultuous few months for the state, which is continuing to grapple with drought, wildfires, and flooding. Experts noted that they don’t expect the state to see an uptick in tornadoes at this time, however, because the specific factors leading to the recent ones were likely unique.
“I wouldn’t say that with climate change, we should expect more tornadoes in California. It’s too rare of an event,” says Judah Cohen, a climatologist at MIT.