Rare Central Valley tornado outbreak: four twisters strike in five hours

But this week, as several thunderstorms moved through, the region experienced something rare: four tornadoes on the same day, all in less than five hours.

The first touched down Tuesday around 2:20 p.m. near Biola, about eight miles from Fresno. Another was spotted an hour later near Atwater. Shortly after 5 p.m., a tornado touched down in Clovis.

The final tornado was an outlier, showing up much farther south at around 6:30 p.m., in Terra Bella in Tulare County, said Alex Cooke, a meteorologist for the National Weather Service’s Hanford/San Joaquin Valley office.

Two of the tornadoes had a strength of EF-1, while the others were EF-0. An EF-0 tornado has speeds somewhere between 65 to 85 mph, while an EF-1 ranges between 86 and 110 mph.

Cooke said forecasters were aware at the start of the day that there was “a lot of spin in the atmosphere” — the kind that could produce a tornado. But it wasn’t immediately clear whether there would be something to pull it and lift it up, “like a figure skater drawing their arms in,” making it faster, he said.

“We weren’t quite sure we had enough of what’s called instability to give us that lift,” he said.

Cooke’s office monitors the southern half of the Central Valley. The last time that area had four tornadoes in a single day was in 2000, and before that in 1996, he said.

That part of the state typically has one or two tornadoes per year, he said, and about 100 since 1955.

Those who experience a tornado in their community should stay away from cars and mobile homes — and go to the lowest floor of a building, Cooke said. Those who have a basement should find shelter there, he added.

“But since most people don’t, the best thing you want to do is get in the most interior room of your house as possible, and put as many walls between you and the tornado as possible,” he said. “Get in there with your kids, your pets.”

Cooke recommended that residents, once they have found shelter, put on helmets if they have them available, or cover themselves with blankets or a mattress.