Why Los Angeles is so susceptible to fires

The devastating fires the struck Los Angeles

Los Angeles is a huge city in Southern California. It’s home to almost four million people—ten million if you include all residents of Los Angeles County. But if you’re thinking of a dense city with lots of tall buildings, think again. LA is spread out.

To put it in perspective, Los Angeles is about 50 percent larger in land area than New York City, despite having less than half the population. This is, in part, because it developed in the age of the car. It’s also because of its geography. Unlike New York and Chicago, Los Angeles is hilly. And the risk of earthquakes on the west coast has necessarily kept building heights low.

Los Angeles is not technically in a desert, but it can feel that way. It’s warm all year round, and rain doesn’t come very often. Summers are long and dry. The winter is when the area gets most of its precipitation, but it often comes in bursts of heavy rainfall. LA gets about 14 to 15 inches of rain per year, compared to an average of 30 inches per year across the entire United States.

LA may be famous for the palm trees that line its glamorous streets and beaches. But a lot of the natural vegetation in the area is drought-resistant shrubs and bushes, and low-growing trees. These plants can survive the long, dry summers without much water.

Another feature of the southern California climate is the Santa Ana winds. These are strong, dry winds that blow in from the inland deserts toward the coast. They usually start in the fall and early winter. They bring dry, warm air from the high interior deserts, downhill toward the coast. As they move through the mountains, they pick up speed.

At the end of a long, dry summer, the Santa Ana winds can further suck moisture out of the air and vegetation.

These are the conditions that Los Angeles faces every year. And it makes the area very susceptible to wildfires—so much so that there is “wildfire season” in southern California. Wildfire season starts in late spring and can last into the fall or early winter, but the peak months for fires are September and October, when the weather is warm, vegetation is dry, and the Santa Ana winds pick up.

Fires can start from lightning strikes, but the vast majority of wildfires are caused by humans. Power lines, sparks from electrical equipment, campfires, cigarettes, vehicles, fireworks, and construction equipment can all set off a dangerous fire. Tragically, some fires are set on purpose.

Fire crews are on high alert during wildfire season because fires can break out with little warning. Sophisticated monitoring systems help detect fires quickly. Remote-controlled cameras on hilltops can spot smoke early. Satellites using infrared sensors can detect pockets of abnormally high heat. Helicopters also circulate, looking for signs of fire during high-risk periods.

People who live in the hills or near dry, open spaces have to prepare for evacuations every year, keeping bags packed just in case. The cost of home insurance has been going up in recent years; some insurance companies refuse to issue policies in the highest-risk parts of California precisely because of wildfire risk.

To a certain extent, then, fires are a fact of life in California. But this year was different—this year was the worst year for wildfires in a long time. Starting on January 7, a series of fires spread quickly through the Los Angeles area. The biggest fires are given names to help emergency responders and the public communicate about them clearly. Between January 7 and the end of the month, there were eight named fires in the Los Angeles area. Three of them combined to cause the most damage. The largest, the Palisades fire, became the most destructive in Los Angeles history, burning 23,000 acres (that’s about 93 square kilometers).

It destroyed almost 7,000 buildings, forced 80,000 people to evacuate their homes, and caused more than $150 billion in damage. People trying to escape abandoned their cars in the roads. The fire left the neighborhood of Pacific Palisades in ashes. Churches, schools, a library, a bank, stores, houses, and museums burned to the ground; the entire downtown area of the neighborhood was flattened.

And that was just one of the many named fires in the area; two other fires burned 10,000 acres each. Dangerous smoke hung over the city, creating health risks for residents. Commuters could see orange blazes on hillsides as they drove home from work. People frantically monitored maps, weather forecasts, and government alerts, trying to assess the risk that they’d lose their homes. Twenty-nine people died in the fires.

The January fires were officially extinguished and the city began the month of February trying to plan how to recover.

Jeff’s take

This was not in a remote desert area. This was inside the borders of the second-largest city in the United States. This was really, really bad.

In the next episode, we’ll look at what Los Angeles is doing to respond, what the rebuilding is like, and, incredibly, the new natural disaster the area faces.