By Ben Gruber

VENTURA, Calif. (Reuters) – Firefighters on Tuesday hoped to take further control of a massive California wildfire, the fifth largest in the state’s history, as relentless wind gusts and bone-dry weather were expected to persist.

The blaze, known as the Thomas Fire, which has burned 231,700 acres in Ventura and Santa Barbara counties about 100 miles northwest of downtown Los Angeles, grew but at a slower pace, the Department of Forestry and Fire Protection (Cal Fire) said.

Strong wind gusts of up to 40 miles per hour (65 km per hour) and extremely low humidity expected through Thursday will pose a challenge to firefighters, the National Weather Service said. (Graphics on ‘Southern California wildfires’ – http://tmsnrt.rs/2jCVLeu)

“That combination of winds and very low relative humidity leads to critical fire conditions and can allow for a potential of significant fire growth and fire behavior,” National Weather Service incident meteorologist Rich Thompson said late Monday at a community meeting about the fire.

About 7,000 firefighters were battling the Thomas Fire, which has destroyed nearly 800 structures including more than 680 homes, Cal Fire said. By Monday night the blaze was at least 20 percent contained.

Dry vegetation that has not burned in 50 years has acted as fuel for the fire in the mountains southeast of Santa Barbara and northwest of Ventura counties, spokesman Ian McDonald said.

“Because the slopes are so steep and the terrain is so rocky, it is actually quite dangerous,” he said. “We are not going to put firefighters in harm’s way halfway up a steep rocky slope. We are going to wait for the fire to come to us and extinguish it where it is safe.”

Public schools in Santa Barbara and school districts nearby have canceled classes this week and will not reopen until the annual winter break is completed in January, said Santa Barbara Mayor Helene Schneider.

Some of the other fires burning over the past week in San Diego and Los Angeles counties have been largely brought under control by the thousands of firefighters on the ground.

The Creek and Rye fires in Los Angeles County were both at least 90 percent contained, officials said, while the Skirball Fire in the exclusive Bel Air neighborhood of Los Angeles was 85 percent contained.

North of San Diego, the 4,100-acre (1,660 hectare) Lilac Fire was 90 percent contained on Monday after destroying 151 structures.

(Additonal reporting by Brendan O’Brien in Milwaukee; Editing by Jeffrey Benkoe)