Could the destructive Mountain fire have been much worse?

Six years ago this week, one of the most destructive fires in Southern California history exploded near the Santa Susana Pass.

Over the next three days, the Woolsey fire would cut a path of destruction through southeast Ventura County and the hills of Malibu, burning literally to the sand next to Pacific Coast Highway. About 1,500 structures were destroyed, almost 100,000 acres were burned and three people were killed.

History has shown that this part of Southern California is prone to major fires, given its susceptibility to intense Santa Ana winds in the fall and winter that hit when the landscape is often its driest.

Last week, that dangerous mix came together again with the Mountain fire, which exploded not far from the 2018 Woolsey fire’s devastating footprint. It has burned more than 20,000 acres, destroyed 134 structures, mostly homes, and damaged 80 others, becoming the most destructive fire for any Southern California community since Woolsey.

A path of destruction

The Mountain fire ignited amid dangerous red flag conditions that officials warned had the potential to create extremely fast-moving fires. Firefighters first responded around 9 a.m. Wednesday to a large brush fire on South Mountain in the Santa Susana Mountains. With intense offshore winds and extremely dry brush, the blaze spread quickly and, by the afternoon, had ripped through hillside neighborhoods near Camarillo.

The area has seen six other major wildfires, with footprints greater than 1,000 acres, since 1986. Most recently, the 2023 South and 2019 Maria fires burned thousands of acres in the western section of the Mountain fire’s perimeter. In 2003, the 108,000-acre Simi megafire burned in eastern Ventura County, reaching a terminus around South Mountain — where the Mountain fire started.

In November 2019, the Maria fire burned along the Santa Clara River, similarly driven by Santa Ana winds. However, it mostly threatened Santa Paula and didn’t reach more urban enclaves.

Ariel Cohen, the lead meteorologist at the National Weather Service’s Oxnard office, called the area a “favorable corridor” for Southern California’s Santa Ana winds, which have fueled many of those recent fires.

Typically, fires make an area less prone to another fire soon after, since they burn up much of the most flammable fuels, which can take many years to grow back. But when fires burn too large and too frequently, as seen in the Camarillo area, the larger, more resilient foliage struggles to regrow, allowing for quick-growing, invasive grasses to take hold — which easily dry out and turn into kindling.

That cycle repeated itself this fall, which saw extreme drying after a hot late summer following two wet years that facilitated growth.

“This was definitely an area with very high vulnerability,” Cohen said. Consecutive 12-month periods with up to twice the normal amount of precipitation produced a lot of “smaller fuels” in the form of underbrush and grasses, he said, “and that ends up being the foundation for fires to very efficiently spread.”

Growth of Woolsey fire in 2018

(L.A. Times)

Could it have been worse?

The Mountain fire could have been a second coming of the 2018 Woolsey fire — or even the the 2017 Thomas fire — but luckily it didn’t pan out that way, said Mark Lorenzen, the Ventura County Fire Department chief from 2012 to 2022.

The Thomas fire, which destroyed over 1,000 structures and burned more than 281,000 acres in Santa Barbara and Ventura counties, also grew under similar circumstances as the Mountain and Woolsey fires: with low humidity, active Santa Ana winds and lots of dry brush in a mixed wildland and urban environment.

“All the conditions were perfect for a fire of this magnitude,” the retired fire chief said. If the windy conditions had persisted longer, Lorenzen thinks this year’s blaze could have been even worse.

An aerial view shows a Camarillo neighborhood before the Mountain fire on Oct. 21.

(Maxar)

Much of the losses occurred during a few hours on Wednesday, when Santa Ana winds were at their worst. That morning and afternoon, 60- to 80-mph gusts slammed the foothills around Moorpark and Camarillo.

The winds were so fierce that retardant-dropping aircraft were grounded, at least temporarily. At the same time, the demand for water from firefighters was so great that some crews lost water pressure, forcing water to be shuttled up to certain areas. Some firefighters on the ground said this created a challenge, but officials insisted it didn’t hinder operations.

By Thursday, winds began to die down, helping firefighters.

The fire was 36% contained by Monday morning as firefighters continued mopping up hot spots before winds could again pick up this week, authorities said.

In the weeks and months that followed the Woolsey fire, there was much debate about whether anything could have been done to minimize the extent of the devastation. A Times investigation found that first responders on the front lines of the Woolsey fire struggled during those first critical hours, stymied by communication breakdowns and a scarcity of air tanker support, equipment and firefighters.

But it’s still too early to say if anything could have been handled differently in the Mountain fire, though officials have praised fire weather warnings and evacuation efforts, pointing to the fact that no one has died in the blaze despite the rapid spread.

“All of our partners and society, they were prepared,” Cohen said.