• Firefighters in LA have limited options against blazes so huge.
• Common tactics like firebreaks, controlled burns, and dousing vital buildings face big hurdles.
• A wildfire expert told BI that the fire is unlikely to be put out until LA's winds change.

Firefighters confronting the Los Angeles wildfires face hurdles to many tactics in their arsenal as they try to tame some 27,000 burning acres.

As of Thursday, more than 1,400 firefighters were battling several blazes with both ground crews and airdrops.

The firefighters of California "are amongst the best-trained and best-equipped wildfire fighters anywhere in the world," said Stefan Doerr, a professor of wildland fire science at the UK's Swansea University.

But, he told Business Insider, "they are really challenged by the fact that the winds are so extreme, as well as having several large fires burning at the same time."

His conclusion: Until the winds fanning the blazes die down, "putting out a fire like this is essentially impossible."

Numerous California officials gave a similar assessment, saying there was no immediate prospect of containing the fires.

'Not prepared'

Anthony Marrone, the fire chief of the County of Los Angeles Fire Department, told local outlet 6ABC: "LA County and all 29 fire departments in our county are not prepared for this type of widespread disaster."

They could handle one or two major fires, he said, "but not four."

Doerr, who did not have direct information about the LA fire services' plans, walked BI through some tactics generally used for major wildfires, and their limitations in combatting these fires.

1) Attack from the side

"This fire is very complex," said Doerr, pointing to the number of distinct blazes, some expanding in several directions at once.

Most of the fires were being pushed toward the sea by powerful inland air currents known as Santa Ana winds.

Doerr said there it is too dangerous to approach so huge a fire from the front, where it burns most intensely.

"It's usually attacked on the side to basically shrink the overall fire front," he said.

2) Use — or make — firebreaks

Common tactics include removing flammable material with bulldozers, he said. "Removing the vegetation is much more effective than trying to fight a fire like this with water."

The problem is that LA's topography is complex, making it hard to remove vegetation, he said.

"That leaves the firefighting forces with limited opportunities," he said. One option is to take advantage of natural firebreaks, such as roads and rivers, or other spots with no flammable vegetation, he said.

There, firefighters could wet the area or use a fire retardant to slow the fire, he said.

Even that, Doerr said, is "very, very challenging" in this instance.

"Even if they are able to basically stop the flames from moving over, say, a road or something directly, the strong winds often mean that you have embers flying over large distances," he said, adding that in some fires, these can travel miles.

That could, in turn, spark more fires, leapfrogging the barriers.

3) Soak important buildings

"When we see firefighters using water, it's often to protect properties — to stop them burning, rather than stopping the entire fire," Doerr said.

As well as ground crews, Chinook helicopters have been dropping thousands of gallons of water on the fire. "It's like having six fire trucks show up to your house every 10 minutes," Wayne Coulson, CEO of the Coulson Group, told Global News.

The fires have put immense strain on LA's water supply.

Three huge tanks of a million gallons each serving the Pacific Palisades ran dry within hours under "tremendous demand," said Janisse Quiñones, chief engineer and CEO of the LA department of water and power, according to The Guardian.

"We're fighting a wildfire with urban water systems, and that is really challenging," Quiñones said, per the paper.

4) Accept losses and prioritize

So many structures are under threat that it is impossible to protect all of them with water. Here, tough decisions have to be made, with important buildings like hospitals likely to receive priority, Doerr said.

More than 1,000 buildings have been destroyed, including the homes of celebrities like Paris Hilton and Billy Crystal.

Another extreme option would be to bulldoze whole streets to create a firebreak, Doerr said.

It would be a desperate measure against some of the most costly properties in the world — but "it's still cheaper than having it burn down, and burning the next building along the road," he said.

"Whether they take these extreme measures at the moment, I don't know, but they have done this in the past in extreme fires," he added.

Some tactics are likely out of bounds

One option that is likely out of reach is what Doerr called a "tactical burn."

When tackling some seasonal wildfires, firefighters light a smaller, controlled fire in the path of the main flames to burn away the available fuel, he said.

This can be really effective — but with the strong winds in LA, it risks making things even worse, Doerr said.

"Otherwise you're just going to generate a new fire that's going to burn further on," he said.

Waiting for the wind to change

Observers are anxiously keeping tabs on a key metric — the percentage of containment of the fire.

But it's often misunderstood. "'Contained' means that you basically stopped the edges of the fire from moving further," said Doerr. 100% containment means authorities are reasonably sure the fire can no longer spread, he said. From there, it can burn itself out.

According to the fire service, two smaller fires were partially contained as of early Thursday, at 10% and 40% each. The larger ones were at 0%.

For all their efforts, LA's firefighters are largely "at the mercy of the weather," Doerr said.

"In reality, most fires of such extremity tend to be stopped by a change in weather," he added.

Winds, which on Thursday were gusting up to 25 mph, are forecast by the National Weather Service to slow down to a maximum of 15 mph by Friday evening, offering the best opportunity yet to stop the blaze.

Until then, Doerr said, "putting out a fire like this is essentially impossible."