Triple-digit temperatures and hot, gusty winds created "critical fire weather conditions" in Southern California on Monday, bringing a threat of rapidly spreading wildfires to the area, forecasters warned.
The National Weather Service issued red flag warnings and fire weather watches across Southern California, stretching from San Diego to Los Angeles, Ventura, and Santa Barbara counties through Wednesday evening. The service said temperatures hovering around 100 degrees on Monday and Tuesday could break records for some areas.
"We're going into an exceptionally hot stretch of weather coming up over the next several days," said Frank Giannasca, a senior meteorologist for The Weather Channel.
A red flag warming signals that "critical fire weather conditions" are occurring or are about to occur. Strong winds, low humidity and high temperatures can combine to trigger "extreme fire behavior," the National Weather Service said.
Temperatures were forecast to reach into the high 90s and the low 100s along the coastline from Santa Barbara and down through San Diego, Giannasca said.
"Even people at the beaches are going to feel the intense heat and high temperatures as you move inland," he said.
Just north of San Jacinto, about 25 miles northwest of Palm Springs, a wind-driven brush fire quickly burned through 50 acres Monday morning, closing State Route 79, a major traffic corridor, the Riverside County Fire Department said.
More than 200 firefighters, supported by three helicopters and four air tankers, raced to keep the fire from spreading in 100-degree conditions with 45-mph winds, Cal Fire said. By midafternoon, it was 75 percent contained.
The heat was expected to continue into Tuesday, with some areas around Long Beach and San Bernardino still around 100 degrees and San Diego in the upper 90s, he said.
"This is impressive to have this. It's just crazy," he added.
The fire warnings come as Californians are enduring the weather phenomenon known as the Santa Ana winds, which bring hot, extremely dry air from inland across the Southern California coast and Northern California.
"You get these areas where the winds are blowing harder, and so ultimately what that sets up is a very hot, very dry and very low-humidity situation with storm winds, and so that increases the fire danger in that area," Giannasca said.
The National Weather Service said the "duration, strength, and widespread nature" of the Santa Ana winds, combined with the extreme heat, "will bring the most dangerous fire weather conditions that Southwest California has seen in the past few years."
"It's just bone dry. Add to that the fact that the temperatures are going to be over 100 degrees, so unfortunately it's the situation where if a fire gets going, it can be become dangerous very quickly," Giannasca added.
California firefighters were mobilizing additional personnel, fire engines, fire crews and aircraft to respond as the state has been dealing with weeks of devastating blazes in the north, the California Department of Forestry and Fire Protection, or Cal Fire, said in a statement Friday.
Cal Fire described the raging northern wildfires as "one of the deadliest and most destructive weeks in California's history."
Five thousand firefighters were battling 10 large fires throughout the state as of Monday, Cal Fire said on Twitter.
At least 42 people have died and more than 8,400 structures have been destroyed since the fires broke out north of San Francisco in California wine country on Oct. 8, according to Cal Fire.