A red flag warning denoting a high risk of wildfire was in effect in the Southland’s valleys, forests and mountains today as a new heat wave gripped the region, prompting precautionary firefighter deployments in Los Angeles and the Angeles National Forest.
The warning for the mountains and valleys of Los Angeles and Ventura counties went into force late Wednesday night in some areas and was taking effect at 6 a.m. today in others, issued by the National Weather Service in response to gusty Santa Ana winds and exceedingly low humidity. If not extended, it will expire late this afternoon and be replaced by a fire weather watch — a notch under a red flag warning — from tonight through Friday afternoon.
NWS forecasters said Southern California would be lashed today by winds of between 15 and 25 miles per hour, gusting at 40 mph and sometimes more, as a result of surface high pressure over the Great Basin. At the same time, a ridge of high pressure over California will generate hot, very dry conditions.
The minimum humidity level expected today through Friday is between 4 and 10 percent, rising only to between 10 and 20 percent during the night, forecasters said.
“As a result, widespread critical conditions are likely over much of Los Angeles and Ventura counties (today), especially the valleys and mountains,” warned an NWS statement, adding that it will become even hotter and drier from tonight through Saturday, but the winds will weaken each day.
Specifically cited by the NWS monitoring station in Oxnard as being under a red flag warning were the San Gabriel and Santa Monica mountains, the Angeles National Forest and San Fernando and Santa Clarita valleys in L.A. County, and Ventura County’s Los Padres National Forest and internal and coastal valleys.
Also in effect, until 3 p.m. today, will be a wind advisory in the San Fernando and Santa Clarita valleys and the San Gabriel and Santa Monica mountains.
The abundance of bone-dry vegetation amid the drought is a major factor in the wildfire threat, forecasters said.
“With extremely dry fuels in place, if fire ignition occurs there could be rapid spread of wildfire that would lead to a threat to life and property,” the NWS statement said.
The Los Angeles Fire Department said it will pre-deploy additional resources starting at 8 a.m. today. These additional firefighters will be deployed at select neighborhood fire stations serving high-hazard brush areas for at least a 24-hour period, with focus placed on the Porter Ranch area, Bel Air, Beverly Glen, Sun Valley and the Shadow Hills area, La Tuna Canyon, Encino, Sylmar, Laurel Canyon, Mulholland Drive and the West Hills/Canoga Park area.
The fire department did not immediately order red flag parking restrictions in wildfire-prone areas that have very narrow roads, hairpin turns and intersections where fire trucks have trouble getting through to fires if cars are parked there.
Officials with the Angeles National Forest announced they would begin stationing additional fire-suppresion resources Wednesday night, with extra engines being pre-positoned and staff warned of ’round-the-clock operations.
The Forest Fire Danger Level has been at “very high” and “conditions are only expected to get worse,” Forest Fire Chief Jim Hall said Wednesday.
Capt. Mike Mohler of Cal Fire also said his agency was moving extra engines and hand crews into Los Angeles County in response to the fire danger expected to last through the weekend.
Afternoon temperatures will climb into the 80s and 90s across the coastal and valley areas today and to between 90 and the low 100s by Friday, said an NWS statement said, adding that a peak in the heat is expected on Saturday with highs of around 106 degrees Fahrenheit.
During the heat wave, which could last into early next week, high temperatures will run 10 to 20 degrees above normal, NWS forecasters said. A slow cooling trend will begin in coastal areas on Sunday, they said.
In Orange and San Diego counties, a heat advisory will be in force from 11 a.m. Friday to 8 p.m. Saturday, but not right at the beach. The hottest temperatures will be from mid morning to late afternoon Friday and Saturday, forecasters said.
NWS forecasters urged residents of the region to protect themselves and their pets from heat stress and to remain well-hydrated. They recommended scheduling any arduous activities for early in the morning or the evening, wearing light, loose-fitting clothing, drinking plenty of water, and treating any sign of heat stroke as a 911 emergency.
The NWS forecast highs today of 79 in San Clemente; 84 in Avalon and on Mount Wilson; 85 in Newport Beach, Palmdale and Lancaster; 88 in Laguna Beach; 90 at LAX; 93 in Saugus; 94 in Downtown L.A; 96 in Pasadena, Anaheim and Yorba
Linda; 97 in San Gabriel, Burbank, Long Beach and Fullerton; and 98 in Woodland Hills and Mission Viejo.
Temperatures will continue to climb until a cooling trend starts Sunday. Downtown L.A. highs, for instance will climb from 94 today to 98 Friday and 99 Saturday then dip to 93 Sunday, 86 Monday and 84 Tuesday. Woodland Hills will be several degrees warmer: 98 today, 104 Friday, 106 Saturday, 105 Sunday, 98 Monday and 94 Tuesday before settling back in the 80s starting Wednesday.