What Starts a Wildfire? Three Potential Causes of California's Active Fires

Multiple wildfires continue to burn in Los Angeles County, with the causes of each blaze under investigation.

Why It Matters

The Palisades fire, which erupted on Tuesday, rapidly ballooned in size to cover more than 17,200 acres. As of Thursday morning, the fire was 0 percent contained.

Two new blazes—the Eaton fire near Altadena and the Hurst fire in Sylmar—also erupted late Tuesday. By Wednesday, two other fires had ignited in Los Angeles County, the Lidia and the Sunset fires.

Thousands of people have had to evacuate because of the blazes, and 421,000 are without power. At least five people have died, and there have been multiple injuries to civilians and firefighters. At times, fire hydrants have run out of water. A state of emergency for Los Angeles' Pacific Palisades neighborhood was declared by Governor Gavin Newsom.

What To Know

Strong Santa Ana winds hit Southern California on Tuesday and Wednesday, creating an environment where rapid fire spread was possible.

The Eaton fire is now at 10,600 acres and is 0 percent contained, while the Hurst fire is at 855 acres and 10 percent contained. The Lidia fire is 40 percent contained at 348 acres, and the Sunset fire, which is at 43 acres, is 0 percent contained.

A firefighter battles the Palisades fire on Wednesday as it burns homes near the Pacific Coast Highway amid a powerful windstorm in Los Angeles County. The causes of the multiple wildfires that continue to burn... Apu Gomes/Getty

How Does a Wildfire Start?

The National Park Service says more than 85 percent of wildfires are caused by human activity. Flames can spark from unattended campfires, burning debris, equipment use and malfunctions, discarded cigarettes and arson, among other reasons.

Fires also can start from natural causes, such as lightning strikes.

Thirdly, power lines can cause wildfires. Power lines can spark and then ignite nearby trees or brush, particularly if environmental conditions are ideal for fires, with strong winds and low humidity. This is why power utilities often conduct planned power outages during favorable fire conditions.

According to the most recent updates from the California Department of Forestry and Fire Protection (CAL FIRE), the causes of all five fires are being investigated.

Oftentimes, when environmental conditions are ideal for rapid fire spread, the National Weather Service (NWS) will issue a red flag warning, which alerts people to the dangers of burning. In addition, California's South Coast Air Quality Management District (AQMD) has issued no burn alerts every day for almost three weeks, advising people against burning.

Active Wildfire Map

As of Thursday morning, the flames from all five wildfires have covered a combined total of nearly 28,900 acres. The largest is the Palisades fire.

A regularly updated CAL FIRE webpage shows the location of each fire, as well as any evacuation orders and evacuation warnings that have been issued.

What People Are Saying

CAL FIRE's most recent update for the Palisades fire: "Extreme fire behavior, including short and long-range spotting, continues to challenge firefighting efforts for the Palisades Fire. Winds gusts up to 60 MPH are expected to continue through Thursday, potentially aiding in further fire activity and suppression efforts."

A spokesperson for the South Coast AQMD told Newsweek: "No-burn alerts are issued when air quality is forecasted to be poor anywhere in the South Coast Air Basin. Emissions from the active fires are expected to cause elevated air pollution levels on Thursday. The alert lets residents in these areas know that burning wood in their fireplaces, or any indoor or outdoor wood-burning device, is prohibited at any time on no-burn days."

What Happens Next

Red flag warnings are expected to remain in place for the Los Angeles area through Friday evening, according to the local NWS office.