Winds Drive Fire Through Mountains West of Santa Barbara

A wildfire burning in the mountains west of Santa Barbara more than doubled in size overnight, driven by fierce "sundowner" winds that have gusted to over 40 mph.

The Sherpa Fire, which started Wednesday in a branch of Los Padres National Forest, had consumed about 4,000 acres (just over 7 square miles) and was just 5 percent contained at midday Friday.

About 1,200 firefighters from the U.S. Forest Service, Cal Fire and the Santa Barbara County Fire Department are battling the blaze, which the agencies say threatens 270 homes.

The blaze has caused repeated closures of U.S. 101, including Thursday evening when the fire jumped the freeway near El Capitan State Beach.

The "sundowners" -- gusty winds that occasionally develop over the Santa Ynez Mountains late in the afternoon and early in the evening -- are expected to be a factor through Saturday.

"You can pretty much set your clock by it, about 5 o'clock in the evening the winds start to pick up," said Eric Boldt, a National Weather Service meteorologist in Los Angeles.

In a press conference Friday, fire managers said they were seeing the effects of the continuing drought in Southern California.

Last winter's El Niño conditions relieved the long dry spell in the northern half of the state. But the precipitation that fell to the south was just enough to sprout grasses that quickly died, adding to the fire danger from long-dead vegetation.

"It is ominous, and we are concerned because the fuels out there are drought-stressed," Santa Barbara County Fire Chief Eric Peterson said.

The windy conditions have been partially offset by relatively high humidity, which has stayed in the 30s during the day and risen to the 60s overnight. Hotter and much drier weather is expected to set in on Sunday.

This post contains reporting from The Associated Press.