Powerhouse fire: Old dry brush proved explosive

The Powerhouse fire has a dance all its own, and firefighters have struggled to keep up with the flames.

When it started Thursday, the fire threatened Green Valley in San Francisquito Canyon. Then it veered west toward Castaic Lake before speeding toward Elizabeth Lake and Lake Hughes, almost overrunning the towns. More recently, it has moved north into the Lancaster area.

The fire was pushed by hot winds but also fed by a potent combination of dense chaparral — some of which hasn’t burned since 1929 — and highly flammable grasses.

PHOTOS: Powerhouse fire

This old chaparral, with layer upon layer of dead growth underneath, has proved difficult to fight. More water drops are needed to extinguish flames, and fire crews have found it hard to cut through.

“That stuff is so dry it just breaks in your hands,” said Chuck Tobias of the Fresno Fire Department as he snapped a gray-white twig and crumbled it between his fingers at the fire base camp Monday. “It lights off like a Roman candle.”

There has been much debate over the years about whether modern firefighting practices – stopping the flames as quickly as possible – can result in larger wildfires later as brush grows unchecked. In some remote areas of the west, fires are allowed to burn. But Nathan Judy, spokesman for the U.S. Forest Service, said Southern California is simply too populated to adopt that strategy.

MAP: Evacuation areas, road closures and more

Chaparral tends to grow taller as it ages, collecting dead material below it.

“So it ends up being more volatile,” said Neil Sugihara, a regional fire ecologist for the U.S. Forest Service. “The overall fuel load on the site becomes much higher and taller, so you get a lot higher fire intensity and a lot more energy released.”

The brush has been desiccated by a near-record lack of rain this year, and officials expect even worse fires whe the traditional Santa Ana winds season begins in the fall.

Elsewhere on the fire line, crews have come across less thick but quick-burning grasses. The grass burns even faster than the chaparral, making it more dangerous for firefighters. Fire officials have used hand crews and bulldozers to build firebreaks as a precaution against flames that can snake unpredictably on grasses.

The Powerhouse fire has burned more than 32,000 acres in the high desert and destroyed at lease seven structures. Calming winds and cooling temperatures allowed firefighters get a better handle on the blaze, which as of Monday night was 60% contained.

Residents fleeing from the flames said they could feel the fire’s approach.

Tracy LaRosa, who lives on the north side of Lake Hughes, saw flames cresting the ridge south of the lake Saturday night. She told herself that if it hit the hill across from the lake, she, her husband, their dogs and birds would flee.

LaRosa said she felt the heat radiating on her as they drove away, and trees were wrapped in flames until they couldn’t be seen.

“You would hear a whoosh and suddenly half the hill had exploded in fire,” the fifth-grade teacher said.

By Sunday, the temperatures began to cool and the fire slowed. But when winds kicked up in the evening, the flames leaped from the mountains and raced across the drought-parched high desert on the western edge of Lancaster.

Temperatures dropped dramatically Monday and humidity levels rose. Even as the afternoon wind began to pick up, fire officials announced that most of those who had been evacuated earlier would be allowed back into their homes.

“What a difference a day makes,” said incident commander Dave Richardson of the Los Angeles County Fire Department.

All residents in the Lake Hughes and Elizabeth Lake areas were allowed back home Monday. They were cautioned to be mindful of fallen trees or downed power lines, and those with private wells were advised to boil their water before drinking or cooking with it.

Residents in the Antelope Acres area remain under mandatory evacuation.

Some experts say constant efforts to tamp out fires before they become larger has caused the thick chaparral to grow more combustible.

Richard Minnich, a geography professor at UC Riverside, has long argued that aggressive fire suppression for small wildfires has created large swaths of land primed to combust because they haven’t burned in many years. The result, he argues, is larger and faster fires that don’t run into enough firebreaks that other blazes can create.

But other scientists point out that some of the most catastrophic wildfires in the history of Southern California happened in places that had seen large fires just a few years before.

These scientists argue that wind-driven fires go through young chaparral and old chaparral alike.

Rick Halsey, founder and president of the California Chaparral Institute in San Diego, said the age of a chaparral “is not really a significant issue when it comes to fire spread and fire size.”

Chaparral is accustomed to intense, periodic wildfires. But simply letting them burn is not the answer, he said. Areas that have burned frequently tend to be overrun by invasive weeds and grass, which Halsey said is even more flammable than old chaparral.

ALSO:

Powerhouse fire containment still days away

Firefighters at Powerhouse fire base camp rest

Crews battling Powerhouse fire dig in for another day of heat, wind