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What You Need to Know About California's Wildfire

Strong winds and dry conditions are making the growing fire difficult to contain.

See the Deadly Fire Unfolding in California

California has been plagued by wildfires over the past few months, and overnight, flames reached deadly proportions in Ventura County. The ongoing disaster highlights the danger and science of wildfires, the conditions that help lead to them, and the increasing risks in a changing climate.

The Ventura County Fire Department describes the current blaze as fast-moving and difficult to contain—as many such wildfires are. In only a few hours, the blaze was able to cover 48 square miles, destroy 150 structures, and leave one dead. Ventura County sits just an hour's drive north from central Los Angeles. As the flames continue to grow, thousands are facing evacuations.

It's a situation the state has faced all too often in recent years. In fact, there are five other active fires and two contained fires burning in and around the Los Angeles area as of this writing. Six additional contained fires can also be found in the northern part of the state.

California, as well as other parts of the West and several other countries—from Australia to Russia—have increasingly seen death and destruction from wildfires. Decades of forest policy have allowed fuels to build, development spreads ever further into former wilderness, and conditions are getting hotter and dryer. In our increasingly fire-prone world, here's how the Ventura fire fits into this bigger picture and may serve as a warning:

How Do Wildfires Start?

While the cause of the Ventura County fire is currently unknown, four out of five wildfires are eventually found to be caused by people. Once lit, flames often grow exponentially.

Ventura County's fire comes on the heels of an especially destructive wildfire. It was reportedly the deadliest in the state's history and fire conditions were aided by California's drought conditions. As of November, southern California was experiencing only moderate drought conditions, but any dry conditions coupled with strong winds are enough to lead to a wildfire. (5 Things to Know About California's Drought Crisis)

Officials are saying the region's infamous and powerful Santa Ana winds are likely also driving the fire.

California is particularly prone to wildfires because it often sees high heat, droughts, and thunderstorms that can ignite trees with lightning strikes. In a recently published paper, some scientists speculated that drought conditions could become worse in California as Arctic ice melts, adding fodder to California's already flammable landscape. (See why some experts think California may have drought-like conditions for a very long time.)

Why Are They So Hard to Contain?

As of Tuesday morning, the more than 500 fire fighters on the scene in Ventura were struggling to contain the flames.

In any situation, to extinguish a fire, it has to be deprived of the three components that help sustain it: oxygen, heat, and fuel. These three ingredients are typically known as the "fire triangle," and fire extinguishers work by eliminating one or more elements of the triangle.

Later today, firefighters will begin deploying aircraft to spray fire retardants, which smother flames and prevent them from getting oxygen. Water dousing is also a traditional method of firefighting.

However, the fire in Ventura County is moving faster than the firefighters can react. Efforts to contain the perimeter are hindered by the area's winds, which topped 50 mph overnight. The National Weather Service estimates these winds will continue until Thursday.

As a precaution, evacuations will continue, as completely containing the fire will likely take several more days. (Read more about California's dry environment in National Geographic magazine.)