When you think about protecting your home from a wildfire, what comes to mind?

Clearing flammable brush away from your house? That’s a great answer. Clearing is critically important, and it is covered elsewhere among these articles, here.

But recent research shows that something else is just as important: protecting your home from burning embers!

Have you ever noticed, in photos taken after wildfires, that many homes have burned to their foundations, but nearby trees are still green? Or that a whole row of homes burned -- except for one? Or even that a home far from the fire was lost?

Why? This is the power of embers.

Embers, or “firebrands,” are burning materials that fly through the air and land outside of the main fire. They can be 1/8 inch or a few inches in diameter -- smoldering pine needles or flaming wood shakes -- and the fire’s hot winds can carry them a mile from the fire!

Since they are on fire, embers start more fires when they land on something dry and flammable. That something could be your home, or something near your home.

So why do some homes close to the wildfire survive, while homes farther away burn? The homes that survived resisted the embers. The homes that burned did not.

Jack Cohen, a researcher with the U.S. Forest Service, has been studying this phenomenon for decades. He has examined the remains and surroundings of dozens of homes destroyed by wildfires.

His work shows without doubt that embers are a main cause of homes burning down, sometimes even where residents have cleared their vegetation.

Jack discovered that “the little things” are critically important: little embers, and the little things that burning embers can ignite, taking the house with them.

What little things? Doormats, cushions on lawn furniture, planter boxes, decorations, doormats, brooms, yesterday’s newspaper. The usual things. And usually these small

flammable items are located on, under, or next to larger flammable items, close enough to catch them on fire.

Consider a fireplace. A tiny match ignites the paper which ignites the kindling which ignites the log. It’s a matter of heating the next larger object until it starts to burn.

Now consider a wood planter box on a deck. An ember will ignite the dead pine needles or mulch on the soil’s surface. The pine needles ignite the box, which ignites the deck, which ignites the siding, which ignites the house. This process can take minutes, or it can take hours. Often embers smolder a long time before flames appear.

   continured above right

A WILDFIRE SCENARIO
For years firefighters have valliantly defended houses from large wildfires, but the houses burned anyway. Why? Let’s learn from an all-too-common scenario.

A wildfire is threatening a group of homes. The residents have been evacuated. Firefighters arrive before the fire and prepare the homes to survive. They move wood piles, remove juniper bushes (which are terribly flammable), and cut dead branches, to reduce the amount of “fuel for the fire” near the homes.

The firefighters can spend only a few minutes at each home. As the fire approaches, they must move on, for their own safety, and to prepare more homes.

But all is not well. Glowing embers have landed on or near the homes. They are hiding in cracks and crannies, under the deck, in corners and gutters. They are slowly heating objects nearby....

The firefighters are busy elsewhere. And the evacuated residents are still awaiting permission to return. So no one notices the first little flames.

Eight hours later, exhausted firefighters finally return to the area. They are shocked. Half of the homes they prepared are smoldering ruins! And they were so sure they would survive! What happened?

The culprit was the hidden embers.

In many cases, the fire’s winds had driven embers through attic or crawl space vents. The vents had screens, but they were in bad shape. Or the openings in the mesh were large. The screens could keep out bats and rats -- but not embers!

Steve Quarles of U.C. Berkeley’s Center for Fire Research and Outreach has discovered that burning embers can penetrate even 1/4” mesh. And penetrate they do: embers in attics are a main culprit in homes lost to wildfires. Once inside vents, embers can smolder for hours in insulation or other items before flames are visible outside. By then it’s too late to save the homes.

The tremendous loss of homes in recent wildfires has prompted the California Fire Marshal to create new building standards for wildland areas. New homes, and major remodels, must have roofs, vents, windows, decking, and siding that resist direct flames, radiant heat, and embers.

What about those of us in older homes? We need to make changes as we can afford them. If your roof is wood shakes or needs repair, that’s your first priority, because the roof is the most vulnerable part of a home.

What about those of us who can’t afford to make any changes? Take heart. Remember, it’s “the little things” that matter the most -- the little things that could catch bigger things on fire. Just keeping flammable items off your deck and away from your house is a great start, and it costs nothing.