Southern California faces critical fire weather conditions this week as a combination of unseasonable heat, bone-dry air and gusty Santa Ana winds elevates wildfire risk across the Los Angeles region.
The National Weather Service issued a Red Flag Warning until 6 p.m. Wednesday for the Western San Gabriel Mountains, Santa Susana Mountains and Southeastern Ventura County Valleys. During this period, any wildfire ignition could spread rapidly, with winds forecast to reach 15-30 mph and gusts as high as 45 mph, while relative humidity may plummet to 5-10%.
"Critical fire weather conditions" are likely, forecasters warn, meaning even a small spark could quickly threaten lives and property. Fire agencies caution that if a blaze starts, the Santa Ana winds and ultra-low humidity could lead to explosive fire growth.
An upper-level ridge of high pressure parked over California is driving the hazardous conditions, bringing clear skies and deflecting rain storms far to the north. The resulting offshore winds, known as Santa Anas, are blowing from inland deserts toward the coast.
Daytime highs Tuesday climbed into the upper 80s to mid-90s across much of the Los Angeles Basin and valleys — about 10-15 degrees hotter than typical for late October. Even coastal neighborhoods that usually stay cooler reached the 80s under the offshore flow, while inland areas hit 90 degrees or higher.
A Heat Advisory remains in effect through Wednesday evening for Los Angeles, Orange County and the Inland Empire. The NWS warns of a "high risk for heat illness" for vulnerable groups such as the elderly, young children and outdoor workers. Officials recommend avoiding strenuous outdoor activities during the hottest part of the day, staying hydrated and seeking air-conditioned relief.
The Santa Ana winds are howling most intensely across higher elevations, including the Santa Monica and San Gabriel Mountains, and adjacent valley corridors. Overnight humidity recovery will be poor, staying only around 15-25% in wind-prone spots Tuesday night, meaning fire danger will remain elevated even after dark.
Grass and brush fuels, which briefly dampened from rain earlier in October, have since dried out again and remain highly flammable.
Residents in hillside and wilderness-adjacent communities should avoid any activities that could accidentally start a fire, including outdoor burning, brush clearing with power tools or improper discarding of cigarettes. Authorities urge residents to be ready to evacuate if a wildfire erupts.
Similar conditions contributed to the massive wildfires that tore through the area in January and officials are already staging resources to prevent another tragedy.
Gov. Gavin Newsom has directed the state's first responders to take early, proactive steps to protect communities. The California Governor's Office of Emergency Services approved the predeployment of 129 personnel and resources to Los Angeles and Ventura counties, including 10 fire engines, three water tenders, three helicopters, three hand crews and three dispatchers with 107 support personnel.
CAL FIRE remains at peak staffing at all units within the impacted region and has full use of both state-owned air assets and exclusive use aircraft to rapidly attack any new fires. Local fire departments have also pre-positioned strike teams in fire-prone areas like the Santa Clarita Valley and Malibu.
By Wednesday night into Thursday, offshore winds are expected to diminish, bringing an end to the most critical fire conditions. As the Santa Ana winds relax, coastal areas should see some cooling sea breezes and higher humidity by later in the week. Forecasts indicate high temperatures will drop back into the upper 70s and 80s Thursday and Friday.
However, the air mass is expected to remain quite dry inland, meaning elevated fire danger could linger through the weekend. No rain is on the horizon through at least the first few days of November.
Residents are urged to prepare a wildfire action plan, including planning evacuation routes and packing a go-bag with essentials. Officials recommend signing up for local emergency alerts to stay informed about changing conditions.
For more information on fire safety and general preparedness, visit Ready.ca.gov. Up-to-date weather information is available at weather.gov.