A dramatic weather shift will greet the Southland Thursday, as cooler temperatures move into the region, followed by weekend rain, replacing an extended period of gusty winds and critical fire conditions.
Red flag warnings of high fire danger are expected to expire at 10 a.m. Friday for the Santa Monica Mountains Recreational Area, the San Gabriel Mountains, the 5 and 14 Freeway corridors, the Santa Clarita and San Fernando valleys, the Malibu Coast, Calabasas and Agoura Hills.
“Most coastal areas will transition to an onshore sea breeze Friday afternoon, resulting in a significant cooling trend from around 80 (Thursday) to high 60s Friday,” according to the National Weather Service. “Valleys and other inland areas should have another warm day.”
A low-pressure system will then move into the area over the weekend. Forecasters said the system was moving more slowly than anticipated, meaning the first rain to fall in the area may not arrive until later Saturday or even early Sunday.
The exact amount of rain expected remained uncertain, with some forecasters indicating between a quarter- and half-inch, but others calling for slightly more. Thunderstorms are also possible with the system.
“For our burn scars, especially the most recent ones this month, chances are still very low, around 5-10%, that (rainfall) rates will exceed the half-inch per hour rate,” forecasters said. “Peak rain rates are generally expected to be a quarter-inch per hour, and for much of the time a tenth of an inch per hour or less.”
High temperatures on Saturday are expected to be around 55 to 60 in coastal and valley areas, dropping by about 5 degrees on Sunday.
Local authorities have been in preparation mode for several days in anticipation of the rain.
Mark Pestrella, director of the Los Angeles County Department of Public Works, said this week crews are preparing for the potential rain, deploying K-rails, sandbags and other devices “to manage sediment and debris.” In the Eaton Fire area, crews were using Santa Anita racetrack as a staging area for supplies, and on the west side near the Palisades Fire, Santa Monica Airport was being used as a base of operations.
“Currently, our crews are clearing debris from streets, cleaning and preparing debris basins, deploying sandbags and other systems to keep runoff with ash and other burn debris from entering the storm drain system,” he said. “Public Works is also working with the state to coordinate the deployment of K-rail in burn areas.”
Pestrella urged burn-area residents who have returned to their homes to plan to stay indoors during the storm event, saying that while officials do not expect the rain to cause damaging flows that would mandate evacuations, sediment and debris will still likely flow into streets.
“This is not expected to be a tremendous amount of debris, but enough to actually cause transportation problems for our first responders that may be trying to travel,” he said. “I’d like to reserve those streets for our first responders.”
He said people who live in homes that back up to recently burned hillside areas can have county crews come to their homes and inspect their properties to see if any mitigation efforts are needed to protect against possible landslides. But he warned: “If … there is a slope behind your home that is burned and it’s maybe 20 feet or more in height, and it is adjacent to the property in any direction, your best bet is not to be in that home when it rains.”
The county Department of Public Works is the lead agency coordinating fire-debris-removal efforts following the Palisades and Eaton blazes, in conjunction with the U.S. Environmental Protection Agency — which is handling the first-phase removal of hazardous wastes — and the Army Corps of Engineers, which will oversee physical debris removal. Officials with those agencies noted that preliminary work on removal has begun, but mainly with assessments and establishing temporary storage areas for debris being removed.
The rain will arrive as firefighters continue to make progress encircling major wildfires that have struck the region in recent weeks.
The Hughes Fire near Castaic Lake burned more than 10,000 acres Wednesday night into Thursday morning, but it was 24% contained as of Thursday afternoon. Late Thursday night, another fire broke out in the Sepulveda Pass, and it ultimately scorched about 45 acres, but was 60% contained by Thursday afternoon.
As of Thursday, the 14,021-acre Eaton Fire was 95% contained, and the 23,448-acre Palisades Fire 72%, according to Cal Fire.
The fires have thus far claimed 28 lives — 11 in the Palisades Fire area and 17 in the Eaton area, according to the county medical examiner.
Evacuation orders have been lifted for dozens of areas in both the Palisades and Eaton fire areas, though some homes were still without electricity and/or gas service due to safety shutoffs. A curfew remains in effect nightly from 6 p.m. to 6 a.m. in the mandatory evacuation areas, with only firefighters, law enforcement and utility workers allowed in those zones.
FEMA Disaster Recovery Centers are open at UCLA Research Park West, 10850 W. Pico Blvd., and Pasadena City College Community Education Center, 3035 E. Foothill Blvd., to assist homeowners with applying for aid.
President Donald Trump is expected to visit California on Friday to view the devastating wildfires in Los Angeles County.
The causes of the Eaton and Palisades fires remain under investigation. They erupted on Jan. 7 as the area was under a red flag warning for critical fire danger due to a historic wind event that saw gusts of 80 mph.
More than 16,000 structures were destroyed in the two fires, according to Cal Fire.
By the time all the damage is assessed, the fires are expected to constitute the costliest natural disaster in U.S. history.