LOS ANGELES (AP) – Ash fell like snow and heavy smoke had residents gasping for air Monday as a huge Southern California wildfire exploded in size again, becoming the fifth largest in state history and driving celebrities from a wealthy hillside enclave.

Tens of thousands have fled their homes as flames churn through foothill towns near Santa Barbara, the latest flare-up after a week of wind-fanned wildfires throughout the region.

With acrid smoke thick in the air, even residents not under evacuation orders were leaving, fearing another shutdown of a key coastal highway that was closed intermittently last week.

Officials handed out masks to those who stayed behind in Montecito, an exclusive community about 75 miles (120 kilometers) northwest of Los Angeles that’s home to stars such as Oprah Winfrey, Jeff Bridges and Drew Barrymore.

Actor Rob Lowe wore a mask as he live-streamed his family evacuating Sunday from their smoke-shrouded home.

“Praying for the people in my area,” he said to his Instagram followers. “Hope everybody’s getting out safe like we are, and thanks for the prayers and thoughts. And good luck to the firefighters, we need you!”

Talk show host Ellen DeGeneres tweeted that neighbors were helping each other and their animals get to safety.

“I’m sending lots of love and gratitude to the fire department and sheriffs. Thank you all,” she wrote.

The blaze – known as the Thomas fire – has destroyed 683 homes, officials said. It was partially contained after burning 362 square miles (937 square kilometers) of dry brush and timber.

Customers coming into Jeannine’s American Bakery in Montecito brushed ash from their clothes and marveled at smoke so heavy that visibility was down to just a…