Photos from the LA fires show how houses catch on fire — and how homeowners can protect their property

• The Los Angeles firestorms show how quickly wildfires can turn into urban fires.
• Flying embers, not direct flames, often ignite homes first.
• Homeowners can mitigate fire risk by maintaining a clear perimeter around their properties.

The firestorms razing Los Angeles show how quickly wildfires can turn into devastating urban conflagrations.

Two fire management experts say there's a common misunderstanding about how homes ignite under these conditions. Understanding how a brush fire becomes urban can help homeowners prepare their properties for future fires.

Take a look at the below photo. Not all the homes on this block are up in flames yet, and blazes in the distance appear to be spaced apart.

"These are scattered ignitions. It's not this wave of destruction," Jack Cohen, a former fire research scientist at the US Forest Service, told Business Insider.

Cohen isn't in Los Angeles, but he studied wildland-urban fires for more than 30 years, both in the lab and in the field. The magnitude of the LA fires is unprecedented, he said, but the process by which they burned down homes probably is not.

It's not a wall of flame or radiative heat from a wildfire that overtakes neighborhoods, he said. Often it's flying embers landing in flammable spots on and around homes.

These "spot ignitions" are like kindling. Embers accumulate on roofs or in yards. Soon ornamental plants, leaf-filled gutters, firewood piles, or deck chairs are up in flames.

If those little fires are close enough to the house, the flames can start to overtake the building.

How homeowners can reduce future fire risk

Homeowners can help prevent future fires from spreading to their homes by maintaining a five-foot perimeter of no flammable materials — no mulch, no ornamental plants, no layers of fallen pine needles, and no piles of wood.

Even better is a 30-foot perimeter that's "lean, clean and green," according to FEMA. If you have that much space around your house, keeping it clear of dead branches and keeping trees and bushes well-spaced can help.

"You are where the rubber meets the road. The things you do on your house and around your house are going to make the difference," Pat Durland, a wildfire-mitigation specialist and instructor for the National Fire Protection Association with 30 years of federal wildfire management experience, told Business Insider.

With the proper perimeter, Cohen said, even homes caught in conflagrations like the Palisades and Eaton fires could survive.

However, photos from the aftermath so far in the Palisades don't seem to show surviving houses unique amid burned blocks.

Cohen noted that trees are still standing in some of those areas, which is visible in live news coverage, showing the fires didn't move through neighborhoods like a wall of flames.

Because embers can travel far, spot ignitions can crop up in various, seemingly random locations throughout a wildfire-adjacent neighborhood. Suddenly a house is on fire here, and another one over there.

Then the houses spread the fire to each other.

Sometimes that happens when a burning house's roof collapses, Cohen said, which sends a convective column up into the wind, which can then push flames into other houses.

Alternatively, the wind can loft burning material from a house and carry it to other homes, igniting new fires.

The extreme winds that have buffeted LA this week spread those embers and bits of burning debris far and wide.

Some houses are close enough to their neighbors that, if the next house has flammable siding — made of wood, perhaps — the mounting flames can quickly overtake it.

Even when houses are close together, building with non-flammable materials can help.

Once houses are up in flames in a place like the Palisades, Cohen and Durland said, it's no longer a wildfire. It's an urban fire.

With thousands of homes ablaze and powerful winds stoking the flames, firefighters have been unable to contain the fires in Los Angeles.

To stop things from getting to that point — before fires ever start — it's crucial for cities and communities to clear dry, highly flammable grasses and brush, whether through controlled burns, livestock grazing programs, or other means.

"This is a team sport, okay? Nobody can solve this alone," Durland said. "It is going to take community planning and it's going to take leadership at the political level and the community level and the state level."