A week of record high temperatures included a red flag fire warning for part of Los Angeles County during what is historically one of the most dangerous times of year for wildfires.

Temperatures are expected to cool slightly this weekend, but not before above-normal heat conditions that warranted extreme heat warnings and advisories until Thursday at 8 p.m. Some areas are expected to reach well into the triple digits on Thursday in the Santa Clarita and San Fernando Valleys.

A red flag warning will be in effect for the western San Gabriel Mountains and highway corridors 5 and 14 until 8 p.m. Thursday. The warning extends to the LA and Ventura mountains.

The warning, which indicates critical fire danger, was issued due to the heat, gusty winds from the northeast and low humidity.

“There is a high risk of the fires growing and unfortunately spreading,” said NBC4 forecaster Belen De Leon. “A lot of this has to do with these temperatures. We are well above normal.”

The warning comes as three major wildfires that started nearly a month ago continue to burn in several Southern California counties. The most active fire, the Line Fire in San Bernardino County, was 79 percent contained at 43,900 acres. Some evacuations remain in effect.

Cal Fire statistics updated Tuesday show 6,528 wildfires have burned 1,001,993 acres so far this year. Last year, in early October, 5,492 wildfires burned 293,462 hectares.

The acreage puts California close to the early October five-year average of 1,085,577 acres.

The community of Big Bear Lake, including Moonridge, Sugarloaf and southern Erwin Lake, were all under evacuation warnings Tuesday. Christian Cázares reports for NBC4 News at 3:00 PM on Tuesday, October 1, 2024.

Fall is typically the worst time of year for wildfires in Southern California due to dry conditions and the infamous Santa Ana Winds, which have fueled some of the region’s most destructive fires.

The temperature will cool slightly on Thursday night, and it will be even cooler on Friday. In areas far from the coast, maximum temperatures will still be 5 to 10 degrees above normal.

Some areas are likely to see further extreme heat warnings or warnings this weekend, with only slight cooling.

Much cooler weather is expected on Tuesday.

Temperature records in Southern California

Some communities broke records for high temperatures on Wednesday.

• Woodland Hills reached 111, breaking the day’s record of 109 set in 1991.
• Palmdale Airport topped out at 105, breaking the 2020 record for the day of 101.
• It was 104 at Lancaster Fox Field, breaking the record for the day of 101 set in 2012.