May 7 (Bloomberg) -- A California wildfire driven by high winds raged out of control today on the edge of Santa Barbara, threatening the homes of 26,000 people and injuring 10 firefighters.

The fire in Santa Barbara County, about 100 miles northwest of Los Angeles, forced the evacuation of 13,000 people, and 13,000 more are on alert, said Sally Nagy, a spokeswoman for the county’s Emergency Operations Center.

The evacuations affected homes within the city limits as well as in outlying areas, she said. Officials haven’t determined what sparked the blaze.

“A lot of people are surprised,” said Max Moritz, 45, co- director of the University of California, Berkeley’s Center for Fire Research and Outreach, in a telephone interview. “It is very early, the plants still appear to be quite full of moisture and when you look at the ferocity of this wind condition, that’s when you say it is surprising.”

Governor Arnold Schwarzenegger, who declared a state of emergency yesterday, said in a press conference today that dozens of homes were destroyed and 125 people were in shelters. More than 1,400 firefighters and 177 engines are battling the blaze, he said, while also giving a tally of the injuries.

‘Explosive’ Conditions

A forecast of temperatures in the 90s Fahrenheit (30s Celsius), dry air and wind gusts as high as 60 mph (97 kph) have set up ideal conditions for “explosive” fire growth, the National Weather Service said.

Firefighters haven’t begun to contain the blaze, called the Jesusita Fire, which started on May 5 and has burned 1,300 acres (526 hectares), the California Department of Forestry and Fire Protection said in a statement on its Web site.

“The large amount of dead fuel content near the Jesusita Fire will lead to a greater threat of rapid fire growth in the region,” according to the National Weather Service in Oxnard, which issued a “red flag warning” for the area.

A red flag warning means conditions exist to promote “explosive fire growth potential,” the agency said.

The blaze is being fueled because shrubs in the fire area have collected decades worth of dried twigs in their canopy, said Moritz, who also does research for the state. The build-up isn’t caused by years of fire suppression, he said, adding that the fires would occur if people were around or not.

‘Catastrophe’ Possible

“There isn’t any such thing as a low-severity fire in the shrub lands,” Moritz said. “The hot, dry wind event has opened the door to what looks like a catastrophe.”

While many other causes of forest fires have been studied, little is known about “fire-weather episodes,” Moritz said. Officials need to learn when to expect these winds and how they will blow fires across Southern California, he said.

“We need to know how we come to grips with this issue because we have built a lot of beautiful towns in dangerous locations,” Moritz said.

More than 32,800 customers of Southern California Edison have lost power twice, each time for less than an hour, since the fire started, said Rudy Gonzales, a regional manager for the company in Thousand Oaks.

Lost Power

Two transmission lines are near the fire area, one taking power to parts of Santa Barbara and Montecito, said Gonzales, whose company is part of Rosemead, California-based Edison International.

“The heaviness of the smoke, the thickness of it, causes the circuit to get overloaded,” Gonzales said by telephone. “It’s similar to the circuit breakers in your house, but on a much larger scale.’

More than 32,000 fires have burned about 1.1 million acres in the U.S. this year, the third-biggest area at the start of a fire season during the past 10 years, according to the National Interagency Fire Center in Boise, Idaho. Last year at this time, 20,473 wildfires had burned about 1.3 million acres.

The agency released its fire forecast last week and said California, Texas, New Mexico and Arizona face an above-average risk of fires.

Schwarzenegger declared the week of May 9 Wildfire Awareness Week to remind homeowners to clear brush within 100 feet (30 meters) of their homes.

“In 2008, we experienced some of the most devastating fires in our history, and as summer comes to a start and we enter our third consecutive year of drought, it is vital that we prepare for this year’s fire season,” the Republican governor said in a statement.

The state’s fire season usually starts in August and lasts till December. Schwarzenegger has said that there is now a year- round risk.

To contact the reporters on this story: Brian K. Sullivan in Boston at bsullivan10@bloomberg.net; Ryan Flinn in San Francisco at rflinn@bloomberg.net.

Last Updated: May 7, 2009 16:20 EDT