Protecting Your Home from

by Don Ogden
via A Guide for the Homeowner
Living with Wildfire in the Inland Empire

SC Climate
Santa Ana Winds
How Fast is Wildfire?
Steps to Defensible Space
Defensible Space
Defensible Home
Evacuation Plan
One Last Suggestion

Southern California Climate

The Southern California climate provides dry summers and mild winters, which create wonderful views and a peaceful living environment. Unfortunately, the San Bernardino Mountains and urban interface areas of California also create the most severe wildfire conditions in the world!

Tragically, each year thousands of acres of California wildland and hundreds of homes are destroyed during a fire season. Protecting the lives and property within our local communities can be enhanced with proactive fire prevention measures.

We hope you will use this guide to prepare your home, your family, your businesses, and your neighborhood for the upcoming fire season and practice fire prevention as part of your daily lives. Please join with us in supporting our local firefighters and fire departments by helping to stop fires before they start.



California Department of Forestry and Fire Protection


How Santa Ana Winds Work

The Santa Ana's get their start in the Great Basin, the vast expanse of desert that covers much of Nevada, Utah and southern Idaho. High pressure over the Great Basin forces cool, dry desert air toward the southwest. There, the winds plunge down through the mountains of Southern California, toward areas of comparatively lower pressure. As they whistle through canyons and valleys of the mountains that separate the desert from the coastal strip between San Diego and Santa Barbara, the air is compressed and heated as it descends, sometimes dramatically. The winds also pick up speed as they travel toward the coast.

"Think of a whole bunch of air getting shot down through a funnel," said Bonnie Bartling, a meteorological technician with the National Weather Service in Oxnard.

Coastal Southern California is normally bathed in cool, moist air blowing ashore from the Pacific Ocean, creating its moderate climate.

Santa Ana's reverse that flow. As they blow through the region, the winds -- which can feel like the blast of heat from an oven -- dry out vegetation and sap the air of humidity, creating the potential for destructive fires.

If a fire does break out in the dry chaparral that carpets many undeveloped areas of Southern California, the gusting Santa Ana's only further fan the flames.

The Santa Ana winds typically blow between September and February. In October and November 1993, the winds exacerbated unrelated fires that charred thousands of acres, killed three and destroyed 1,000 buildings in Malibu, Altadena and Laguna Beach.

One benefit of the Santa Ana's is that the winds push out to sea and disperse smog from the Los Angles region.The winds were named by settlers in the area of Santa Ana, a city 40 miles southeast of Los Angeles.


Dry, hot and windy weather increases the likelihood of a major wildfire. High windspeeds, in particular, can transform a small, easily controlled fire into a catastrophic event.These conditions:

  • make ignition easier
  • help fuels burn more rapidly
  • increase fire intensity


Fuel is required for any fire to burn. In a wildfire, fuels are usually living vegetation (trees, shrubs, brush, grass) and dead plant materials (dead trees, dried grass, fallen branches, etc.) Homes, when in the path of wildfire, can become fuel. The quantity, size, moisture content, arrangement and other fuel characteristics influence the ease of ignition, rate of fire spread, length of flames and other fire behavior.


Of the topographic features, the steepness of slope is among the most influent' on fire behavior. The steeper the slope, the faster a fire will spread. Other important factors are:

  • "aspect"– south and southwest slopes usually have more fires
  • "chimneys"– steep, narrow drainage

Endangered Species

Federal and state regulations have been established to protect rare and endangered plants and animals that live in wildfire country. Whenever there is any doubt about clearing or thinning native brush, the US Fish and Wildlife Service and State Fish and Game Department should be consulted.

Human Environment

As people move into wildfire country, the human-built environment become important in predicting loss of life and property. Following are examples of increased risk to people living with the threat of wildfire.

  • Combustible construction, especially roofs
  • Narrow roads, limited access
  • Lack of fire-smart landscaping
  • Inadequate water supply
  • Poorly planned subdivisions


How Fast is Wildfire?

The speed of spread and flame length would increase greatly during seasonal dry winds like "Santa Ana's."


Firebrands are burning embers produced by wildfire which are lifted high into the air and carried beyond the fire front. Firebrands are one of the major causes of homes burned due to wildfire.

Typical firebrand materials include pieces of burning vegetation, and, if houses are involved, wood shakes and shingles. Depending on wind speed and size of materials, firebrands can be carried more than 1 mile ahead of the fire front.

A shower of thousands of firebrands can be produced during a major wildfire event. If these firebrands land in areas with easily ignited fuels—including wood roofs—numerous spot fires can start. Homes located blocks away from the main fire front can be threatened.

Below are three examples of vegetation common to our region with computer-generated estimates of how each would burn under common fire weather conditions. Predictions are based on a 20 MPH wind and a 20% uphill slope. Fuel moisture content is based on normal weather for August in our area.

Grass Fire

Speed: 4 miles per hour
Area: 2.5 acres per minute = (6 football fields per minute)
Fire size in 6 minutes: 27 acres
Flame length: 8 feet

Grass and Brush Fire

Speed: 1.7 miles per hour
Area: 4/5 acre per minute = (1.1 football fields per minute)
Fire size in 6 minutes: 5 acres
Flame length: 12 feet

Tall Chaparral Fire

Speed: 8.3 miles per hour
Area: 6 acres per minute = (8 football fields per minute)
Fire size in 6 minutes: 36 acres
Flame length: 47 feet

Steps to Defensible Space


You can use wooden kitchen matches to get a better idea of how fire behaves on sloping ground.

  • Strike the first match and hold it upright as shown. Note how long it takes for the flame to reach your fingers. Dispose the burned match safely.
  • Strike a second match and hold it in a horizontal position to see how this angle increases the speed of the flame.
  • Angle the third match downward and you'll discover how rapidly it burns. This third position is the situation of steep slopes with the fuel preheating the vegetation or structures.


The first goal in creating a defensible space is to selectively remove plants, then prune to reduce fuel volume of the plants that remain.

Sometimes wildland plants and even landscaping can occur as an uninterrupted layer of vegetation as opposed to being patchy or widely spread individual plants. The more continuous and dense the vegetation, the greater the wildfire threat.

If this situation is present within your recommended defensible space area, you should "break-it-up" by providing for separation between plants or small groups of plants. Clear dry vegetation in cooler, earlier hours, not in the heat of the day. Remember, if it's too hot outside for you to be working, it's too hot to be using equipment for clearing brush.


Vegetation is often present at varying heights, similar to rungs on a ladder. Under these conditions, flames from fuels burning at ground level can be carried to shrubs, which can ignite still higher fuels like tree branches. The ladder fuel problem can be corrected by providing a separation between the vegetation layers.

Within the defensible space area, a vertical separation of three times the height of the lower fuel layer is recommended.


Landscaping with wildfire in mind–"firescaping"–involves plant selection based primarily on the plant's ability to reduce the wildfire threat. Minimize the use of evergreen shrubs and trees within 30–50 ft. of a structure, because junipers, other conifers and broadleaf evergreens, such as eucalyptus, contain oils, resins and waxes that make these plants burn with great intensity. Use ornamental grasses and berries sparingly because they also can be highly flammable.

Choose "fire smart" plants. These are plants with high moisture content. They are low growing. Their stems and leaves are not resinous, oily or waxy. Deciduous trees are generally more fire resistant than evergreens because they have a higher moisture content when in leaf, but a lower fuel volume when dormant.

Contact the California Department of Forestry & Fire Protection or your local fire department for recommendations or for referrals to local experts for appropriate fire-resistive planting options for your particular area.


A fire resistant plant can lose this quality altogether if not properly maintained and irrigated. Lack of long term attention can result in fire-resistant plants loading up with dead twigs, leaves and branches, to grow into monstrous, yet sometimes invisiblefuel volumes.

Drip irrigation, plus periodic pruning and cleaning can maintain the fire-resistiveness as well as the appearance of landscaping.


Federal and State environmental regulations might, at first, appear to conflict with fire protection planning concepts. Environmental law should not be ignored in preparing for wildfire. Cooperation between environmental regulators, fire agencies and property owners has resulted in an agreement to allow a 100 ft. clearance from existing structures. If endangered species are encountered, contact environmental agencies for guidance.

Defensible Space

The Three "R's" of Defersible Space.

REMOVAL - Eliminate entire plants, particularly trees and shrubs from the zone. Examples: cutting down a dead tree or cutting out a flammable shrub.

REDUCTION - Remove plant parts such as branches or leaves. Examples: pruning dead wood from a shrub, removing low branches and mowing dried grass.

REPLACEMENT - Substitute more hazardous vegetation with less flammable plants. Examples: removal of a dense stand of flammable shrubs and planting an irrigated, well-maintained flower bed.


Zoned Fire-Resistant Landscaping

Zoned fire-resistant landscaping helps protect your home from wildfire. The size of zones shown below may not be adequate for your home. Native vegetation, terrain and local regulatiions may make greater distances necessary. Contact your fire department for specific requirements.

ZONE 1 - 30-50 feet* minimum from structures)
The area nearest your home should contain low-growing plants with low fuel volume. Ideally there should be no tall-growing plants this close to your home. However, since we all enjoy the shade of a tree or two, select the tree wisely–see Steps to Defensible Space
step 4.

ZONE 2 - (a minimum of 30-100 feet from structures)*
Low-growing ground covers that are resistant to fire and low in fuel volume are recommended in this zone. When properly maintained, a fire may be stopped before it reaches your home.

ZONE 3 - (70-100 feet from structures)
This is a transition area that has been planted with low fuel-volume plants and native vegetation that has been thinned to reduce fuel volume. When thinning, try to leave 20 feet of space between large shrubs and trees. Remove ladder fuels. The width of this zone depends largely on the type, size, and density of native vegetation, and the steepness of slope, and exposure.

NATIVE VEGETATION - (beyond 100 feet from structures)
Check with environmental regulatory agencies before modifying native vegetation that might include endangered species and habitat. Note that 100 feet of zoned fire-resistant landscaping may not be adequate to protect your home under all circumstances, but protects well in most situations.


Defensible Home

Things You Can Do To Better Protect Your Family And Home From Wildfire

In a wildfire, firefighting forces are stretched to the limit. You can design or modify your home to resist wildfire—or it can be totally unprepared and indefensible.

A Defensible HOME has a far better chance of survival—whether or not firefighters can get to it in time!

The manner in which a house is designed, location where it is built, materials used in its construction, and fire department access, all influence survivability during a wildfire. These recommendations are primarily from the California Department of Forestry and Fire Protection's "How to Make Your Home Fire Safe." When coupled with an effective Defensible SPACE, these recommendations will make your home much easier for firefighters to defend and improve its chances of survival in a wildfire.

New homes in wildfire country have fire-resistive walls, non-combustible roofs, fire-smart landscaping, residential fire sprinklers, good access, water supply, and a defensible space.



The Wood Shake and Shingle Roof Hazard

Your home can be threatened by wildfire in three ways:

  1. Direct exposure to flames
  2. Radiated heat
  3. Airborne firebrands

Of these, firebrands account for the majority of homes burned by wildfire. The most vulnerable part of a house to firebrands is the roof.

Because of its angle, the roof can catch and trap firebrands. If the roof is constructed of combustible materials, the house is in jeopardy of igniting and burning.

Not only are combustible roofing materials a hazard to the structure they cover, but also to other houses in the vicinity. Burning wood shakes, for example, can become firebrands, be lifted from the burning roof by a thermal column of rising smoke and flames, and be carried blocks away, igniting other combustible roofs.

Unfortunately for owners of existing combustible roofs, there are no long-term reliable measures to reduce roof vulnerability to wildfire — other than re-roofing with non-combustible materials.

The Right Stuff

A home designed and maintained with the right stuff and wildfire in mind is as follows:

We must all keep in mind that wildfire is a dangerous and unpredictable problem, and there is no sure way to protect a home under every situation. What we can do is take full advantage of every opportunity available in the hope that it will be enough to save a home.

Evacuation Planning
Get Ready

Long before fire threatens, plan your evacuation.

Make a list of items you want to take with you during an evacuation. Here's an example, but prepare your own list.

Important Stuff

Emergency Supply Kit

When fire threatens, you won't have time to shop or search for supplies.

Assemble an Emergency Supply Kit that includes items you'll need if you have to evacuate.

Store them in easy-to-carry containers such as back-packs, plastic crates...

Get Set

When evacuation seems likely, put your plan into action.

Take a deep breath, and remember that you have planned well. Remember, too, that lives always take priority over property.

And if there's time...

Get moving! GO

Two Ways Out

Just as your home escape plan should include two ways out of every room–in case the usual way out is blocked by fire...

Leaving Your Home


A Pre-Arranged Meeting Place

And just as you should have a place to meet outside your home, to be sure everyone's out, your evacuation plan should consider alternate routes out of your neighborhood, in case the usual route becomes blocked. When local phones are disrupted in a disaster, long distance lines are often still functioning. It's wise to pre-arrange with a distant relative or friend to call them in a local disaster to let family members know you're OK.

If you let that distant contact know that your family has evacuated and is safe, other distant family members (who know of the plan in advance) can check in with them too, and learn where you are and that you're OK. (This long-distance communications "family check-in plan" also works in an earthquake.) And that Disaster Kit you've assembled for wildfire evacuation, will also serve well in an earthquake or other disaster.

Leaving Your Neighborhood


One Last Suggestion