Why the California wildfires were nearly impossible to contain

A perfect storm of weather and climate conditions made the California wildfires nearly impossible to contain once they ignited, according to experts.

In a typical fire management scenario, containing the fire by setting up a perimeter and trying to keep it from spreading further is often the first line of defense for firefighters to get the blaze under control, according to Lenya Quinn-Davidson, director of the University of California Agriculture and Natural Resources' team of experts on fire research in California.

But a confluence of events -- hurricane-force winds, low humidity levels and dry conditions -- allowed the fires to explode after the initial spark, Rachel Cleetus, policy director for the Climate and Energy Program at the Union of Concerned Scientists, told ABC News.

Trying to contain the fire under the wind scenario was "untenable," Quinn-Davidson said.

"Keeping people safe was the No. 1 objective -- evacuating people, keeping firefighters safe," Quinn-Davidson said.

The fires have prompted mandatory evacuation orders for tens of thousands of people and ripped through entire neighborhoods in a matter of hours. At least five people have died and several others were injured as a result of the fires, according to officials late Thursday.

What we know about the containment of the wildfires so far

Five separate wildfires in the same region is proving difficult for firefighters to contain as they battle the flames amid high Santa Ana winds.

The Palisades Fire, which had burned through more than 19,000 acres in the Pacific Palisades neighborhood in Los Angeles County, was 6% contained as of Thursday night, according to the California Department of Forestry and Fire Protection, known as Cal Fire.

Also in Los Angeles County, the Eaton Fire has burned more than 13,000 acres near the Altadena and Pasadena neighborhoods and is 0% contained, according to the state fire agency.

The Hurst Fire, burning near Diamond Road and Sylmar in Los Angeles County, was about 10% contained on Thursday as it dropped from nearly 1,000 to less than 700 acres burned, according to Cal Fire late Thursday.

The Woodley and Sunset fires were brought under control after sparking on Wednesday,

The Lidia Fire, spanning over 300 acres on Canyon Road in Los Angeles County, was 60% contained on Thursday, according to Cal Fire.

The Kenneth Fire, which crossed through both Los Angeles and Ventura counties, grew close to 1,000 acres with zero containment as of Thursday night.

"Right now, it is still a very, very dangerous situation, and anybody in that zone needs to evacuate," Cleetus said.

Why firefighters weren't able to contain the fires immediately

Several meteorological impacts contributed to the inability to contain the fires quickly, including humidity as low as 10% and a windstorm with gusts up to 100 mph that carried embers far and wide to ignite a tinderbox landscape Just 0.16 inches of rain has fallen in the region since May, according to meteorology and fire experts, leaving the landscape parched.

Containing the fire as winds gusted at those speeds in some spots would have been virtually impossible, the experts said.

"This is just a catastrophic influence of factors that has made it really, really difficult to contain these fires," Cleetus said.

In addition, the urban setting makes managing these types of fires much more difficult, the experts said.

In Northern California, where fires tend to be fueled by large amounts of brush in forests and wildlands, firefighters can better manage them through fire-suppression activity, Quinn-Davidson said.

But in a populated region like Los Angeles County, the spread is moving quickly from house to house as people try to evacuate -- in this case even ditching cars that block roads in an attempt to outrun the flames, Quinn-Davidson said.

"There's nothing more dangerous and difficult than fighting in close and urban settings," Cleetus said.

In addition, the firefighters have been using residential water supplies and have seen some instances where hydrants ran dry, Quinn-Davidson said.

Climate change also played a role in the severity of the fires

Wildfires are a natural and necessary part of Earth's cycle, but climate change and other more direct human influences have increased their likelihood, research shows.

Wildfires in the western U.S. have become larger, more intense and more destructive in recent decades due to a combination of factors, including rapid urbanization and human-amplified climate change, according to the federal government's Fifth National Climate Assessment, a breakdown of the latest in climate science, published in November 2023.

Warming temperatures, drier conditions and shifts in precipitation are contributing to an increase in the frequency of large wildfires and acres of land burned in the U.S. each year, according to the National Oceanic and Atmospheric Administration.