LOS ANGELES — Cool temperatures and moist air are expected to continue to help firefighters get a handle on a massive wildfire near Thousand Oaks through the weekend, with a 50 percent chance of rain on Sunday.
High temperatures throughout most of the region were forecast to drop to the low 60s and mid-70s Saturday from just over 90 degrees the day before, said Scott Sukup, a meteorologist for the National Weather Service.
The cooling weather and rising humidity levels caused the weather service on Friday night to cancel red flag fire warnings in the area.
The humidity, a measure of moisture in the air, was expected to rise steadily through Saturday, officials said. “It should rise to about 60 to 70 percent as the day goes on, climbing higher overnight,” said Sukup, who noted that when the Springs fire began in the Thousand Oaks area Thursday relative humidity was about 5 percent.
The cooler, damper air is part of a marine layer that Sukup said would affect much of Southern California over the next several days. The chance of rain will rise to about 50 percent Sunday and Monday. Sukup said temperatures in in the Springs fire area will continue cooling, reaching the low to mid-60s as the week begins.
While the wetter air helps suppress the blaze, one firefighter noted a Catch-22: The humidity actually hampers efforts to steer the fire with controlled burns of flammable vegetation.
“There’s too much humidity right now, we’re going to try to get this going again,” said Ventura County Fire Capt. Scott Dettorre, noting the trouble firefighters were having Saturday morning as they tried to stoke a controlled burn on a hillside in the Thousand Oaks area. “Otherwise, you get an incomplete burn.”
More than 1,000 firefighters were battling the Springs fire, which began Thursday near Camarillo. The fire has burned more than 28,000 acres, charring canyons and closely approaching homes in the affluent area of Hidden Valley. The fire was 30 percent contained by Saturday morning.
The Ventura County blaze and several smaller fires throughout Southern California have raised concerns air quality. With smoke pushed by offshore winds dispersing inland, officials have issued an alert covering most of the region and urging the elderly, children and anyone typically affected by air pollution to remain indoors, especially in locations near the fires.
The potential for explosive fires became apparent on Tuesday when Cal Fire authorities and federal meteorologists determined that ominous weather patterns were setting up over Southern California: hot Santa Ana winds, temperatures in the 90s, low humidity and tinder-dry vegetation.
In a pre-emptive move, Cal Fire authorities placed engines, hand crews and equipment on alert statewide.
“We knew big fires were imminent; we just didn’t know where,” Cal Fire Battalion Chief Nick Schuler said. “That same Tuesday, the Summit fire erupted in Riverside County and quickly burned 2,956 acres.”
The next day, the Panther fire began charring more than 6,700 acres in the Northern California community of Butte Meadows. On Friday, five fires were reported in San Diego County, along with many more fires elsewhere.
Shortly after it erupted, Cal Fire authorities and Ventura fire authorities determined that the Springs fire would become a major incident, based on incendiary weather conditions, and the potential for significant structural losses.
“A decision was made to dispatch resources from across the state to Camarillo,” Schuler said.