An exceptionally strong storm system swept through the Central Valley this week, bringing with it a rare weather phenomenon more common in the plains of Kansas than California: an outbreak of tornadoes.
On Tuesday, four twisters touched down in a single day, including in areas close to Fresno and Atwater, a remarkable number in a state that sees an average of just nine tornadoes per year. The National Weather Service confirmed the fourth tornado in a report on Thursday, finding that the strongest twister measured as an EF1 with winds peaking at 110 mph.
Surveillance video shows one of the twisters demolishing a structure at a market in Terra Bella. And photos released by the weather service show roofing material on power lines after being pulled off buildings.
Weather service meteorologist Emily Wilson said this is only the third time since 1955 that more than three tornadoes were reported in the area in a single day.
“It’s very unusual to have four tornadoes in one day,” she told SFGATE. Wilson explained that specific weather conditions on Tuesday, including wind direction and an elevated amount of cape, or energy for the storm, made the tornadoes more likely to form.
“The air had a great propensity to spin,” she said of Tuesday’s weather patterns.
In the U.S., tornadoes are often associated with “Tornado Alley”, or the flatlands of the plains. On Thursday, a massive tornado that touched down in Oklahoma destroyed multiple homes and led to the temporary shutdown of a U.S. Air Force base.
But this weather phenomenon can pop up anywhere in the U.S. The violent storms are increasingly striking the southeastern states, and experts warn a changing climate is leading to more volatility, making dangerous storms more common in California.
Peter Roopnarine, the geology curator for the California Academy of Sciences, said California already is seeing signs of climate impacts as winter temperatures increase and precipitation becomes more variable.
“We should probably expect a higher frequency of strong storms,” Roopnarine told SFGATE.
Roopnarine also highlighted hotter temperatures in the Pacific Ocean, which can increase the risk of damaging storms along the West Coast.
“You can get a lot of moisture coming up from the south, for example, and the water temperatures, the ocean temperatures are warmer, and all of that adds energy to the atmosphere,” he said. “Which means that not only can you increase the frequency of storms, but you should expect some of those storms to be exceptionally strong.”
And while tornadoes remain relatively rare in the state compared with Oklahoma, Roopnarine said Californians may someday have to learn new safety procedures for dealing with dangerous weather.
“I’m not sure that the general population here knows how to respond during a tornado warning,” he said.