What you need to know
Evacuation orders are still in place for the Eaton and Palisades fires in Los Angeles County, nearly a week after they started during the Santa Ana storm. Strong winds returned Monday night and will continue in parts of Southern California into Wednesday. A red flag warning is issued indicating dangerous wildfire conditions. In some areas, a Particularly Dangerous Situation (PDS) Red Flag Warning is issued, indicating elevated fire conditions beyond the normal Red Flag Warning.
Winds will pick up even more as two large wildfires break out in Los Angeles County on Monday, triggering a red flag warning for parts of Southern California ahead of a more severe fire warning. .
Red flag conditions returned after the weekend when winds eased, allowing firefighters to ramp up containment of the Palisades and Eaton fires, two of California’s most destructive wildfires on record. The fire broke out on January 7th during a powerful Santa Ana rainstorm.
This week’s strong winds will begin Monday night and continue into midweek.
“The strongest winds will begin (Monday night) and continue into Wednesday morning,” NBC4 meteorologist Shana Mendiola said. “At that time, a red flag warning is displayed, and within that red flag, a particularly dangerous situation (PDS) red flag is embedded.”
A red flag warning indicates dry and windy conditions that can lead to rapid spread of wildfires. Areas with a PDS red flag may experience weather conditions that exceed the normal red flag.
“The National Weather Service issues this when there is a truly critical situation,” Mendiola said.
The Eaton Fire in Altadena has burned more than 14,000 acres and is 27% contained as of Monday morning. Michelle Valles reported on NBC4 News on January 13, 2025 at 4 a.m.
When the Palisades and Eaton fires broke out a week ago, large areas of Southern California were under PDS red alerts. Fueled by strong wind gusts of up to 90 miles per hour, the fire engulfed the entire neighborhood in what firefighters described as the worst conditions they had ever seen.
“(The wind) won’t be as strong as the last race, but look at how that wind continues. The wind is steady,” Mendiola said. “There will be gusts and occasional gusts of wind that can cause problems.”
This week’s forecast calls for winds of 20 to 50 mph, with gusts reaching 110 mph in isolated mountain areas.
“There is a risk of fire throughout Los Angeles County,” Los Angeles County Fire Chief Anthony Malone said.
Here’s what you need to know:
What areas of LA are under red flag warnings?
The red flag warning will be in effect from 10pm Tuesday until midday Wednesday, but may be extended. Areas under warnings are expected to experience extreme fire danger due to calm Santa Ana winds and low humidity.
These areas include the mountains and coast of Ventura County, Malibu, the Santa Clarita Valley north of Los Angeles, parts of the San Fernando Valley, the San Gabriel Mountains, much of interior Orange County, and parts of the Inland Empire.
heads up! Locally damaging, strong northeast/easterly winds will affect much of western Los Angeles and Ventura County through Wednesday. With severe fire weather expected, prepare in advance by having multiple ways to receive notifications when new fires occur. #VenturaCounty #LA #coke #SoCal pic.twitter.com/BuvqcwnktS
— NWS Los Angeles (@NWSLosAngeles) January 12, 2025
Which areas raise PDS red flags?
The High Level PDS Red Flag Warning goes into effect at 4 a.m. Tuesday and covers three areas in Los Angeles and Ventura counties.
5 Freeway corridor in northern Los Angeles County known as the Grapevine. The area extends from the San Fernando Valley to Ventura County, including Ventura, Fillmore, Simi Valley, and Porter Ranch. The western Santa Monica Mountains above the Los Angeles County coast.
The Los Angeles Basin and the Eaton fire area northeast of Los Angeles will be protected from the strongest winds. Last week’s storm reported strong wind gusts in areas that typically don’t have the strongest winds.
Strong winds are not the only threat. On Sunday, during a lull in winds, the Palisades Fire burned in the Mandeville Canyon area west of Highway 405, burning through dry brush that provided ample fuel for the flames. Many of Southern California’s foothills are covered in dry brush after a dry start to the region’s rainy season.
The increased fire danger continues into Wednesday.
Early Monday morning, about 92,000 people in Los Angeles County were under evacuation orders due to wildfires. Some areas were downgraded to evacuation orders on Sunday due to a repopulation. In other words, residents need to prepare for evacuation.
What is Santa Ana style?
Wind moves from high pressure to low pressure. When combined with the rugged terrain of Southern California’s mountains, canyons, and passes, the winds moving through the area can increase their speed.
“They are unique to our region because of the topography,” Mendiola said. “High pressure and low pressure have a lot to do with this. Our winds flow from highlands to lowlands and through passes and valleys. We call this offshore wind. It comes from the desert through a mountain pass and is compressed downhill. ”
Once the air reaches the top of the mountain, it rushes down, picking up speed like a bicycle without brakes. Canyons and passes serve as toll roads. As the winds combine and pass through the canyon, they shoot out in powerful gusts.
And the wind that travels down the mountain dries as it sinks. This is more physics than meteorology, but this dryness lowers humidity into the single digits. The combination of dry fuel, low humidity, and strong wind gusts creates a significant fire threat. Once a fire starts, it can spread quickly and gusts of wind can cause it to behave abnormally.
Santa Ana winds occur in the fall and persist through the winter.
