| Observations from the 2003 Southern California
Wildland Fires
Masonry Home >
Products and Properties > 2003 Southern
California Wildland Fires
by Mark Kluver, P.E.
 History
has a way of repeating itself. In 1993, I traveled to Southern California
to investigate the aftermath of the wildfires that occurred in October
of that year. This was followed by my publication of an article
on the subject in the January-February 1994 edition of Building
Standards magazine. Almost exactly ten years later to the day,
wildland fires again swept across Southern California from Ventura
County to the Mexican border. What sets the recent fires apart was
their size and the amount of destruction they caused, burning more
than twice the area (approximately 745,800 versus 333,700 acres)
and destroying well over three times as many dwellings (approximately
3,340 versus 971 dwellings) as compared to the 1993 fires. By the
time the fires were subdued by wet, cool weather, 23 people had
been killed and 174 injured. State officials estimate that damages
from the fires will exceed $2 billion: the largest property loss
from wildfires in the state’s history.
Contributing Factors
 Many
factors contributed to the tremendous loss of life and property—some
new, but most recurring. In late October or early November of most
years, for example, hot winds blow off of the upper deserts and
through the dry Southern California mountain ranges. In addition,
forests in the region had experienced a multi-year drought, followed
by a bark beetle infestation that killed huge stands of trees. The
drought also created enormous amounts of fuel in the form of kiln-dried
chaparral shrubs on lands near the Pacific Ocean, especially in
San Diego County. Given these conditions, a spark was all that was
needed to ignite a conflagration that the hot, dry winds could spread
uncontrollably.
There is no question that population growth and development in urban-wildland
interface areas have also increased the risk of catastrophic fires.
“There is almost a direct correlation between growth and the
number of ignitions,” says University of California, Berkeley,
professor Tim Duane, whose statistical survey of California’s
Sierra Nevada mountain range indicates that a doubling of population
may be responsible for a 5,000% increase in property damage.1
Also, some housing has been built in so-called “indefensible
locations” such as Palmer Canyon in the foothills of the San
Bernardino National Forest, where 47 houses once stood but only
4 remain. Other examples of indefensible locations include the narrow,
miles-long canyon containing the Hook Canyon community where 350
homes burned and Crestline, a neighboring community that contained
dozens of closely spaced wooden houses surrounded by dry, brittle
pine trees which overhung roofs and porches.
The San Bernardino Mountains had not experienced a severe burn in
nearly 100 years, in part due to the U.S. Forest Service’s
policy of suppressing fires, leaving the forests with an unprecedented
buildup of fuel. In fact, two months before the fires, Texas A&M
University forest ecologist Thomas Bonnicksen warned Congress, “never
have I seen anything more dangerous than the overgrown, beetle-ravaged
forest. […] I am concerned for the safety of people living
in communities surrounded by these forests.” 2
Local politics also contributed to the problem. In the community
of Lake Arrowhead, for example, a homeowners association had a longstanding
policy of banning property owners from cutting trees in order to
help preserve the area’s natural beauty. The ban was lifted
a year ago and some residents did what they could to remove the
dead pines, but the buildup of dead trees was too dense.
Mitigation Features
Despite the high losses experienced in the 2003 Southern California
wildfires, the results could have been much worse if not for changes
made in the wake of the 1993 fires. While many homes were lost,
the adoption of local ordinances requiring special protection against
wildland fires was critical to the preservation of tens of thousands
of other dwellings along the several hundred miles of fire perimeter.
Local adoption was helped along in part when state lawmakers passed
the Bates Bill following the devastating Oakland Hills fire in October
1991. That legislation required the State Fire Marshal to designate
high-hazard fire-risk zones and permitted local governments to require
stricter building standards within these zones.
 |
| The unique roof eaves and soffits of this
undamaged Ventura County home are consistent with the most stringent
fire protection requirements of the International Urban-Wildland
Interface Code. |
Local jurisdictions throughout California have set different standards
for building in high-hazard fire-risk zones. While few have specifically
adopted comprehensive mitigation provisions such as those provided
by the International Urban-Wildland Interface Code™ (IUWIC™),
most of the homes recently built in areas of high risk have at least
some special features common to that code (see
Table 1). The building features that appeared to have provided
the most protection in the recent wildfires were noncombustible
(or Class A) roofs and noncombustible exterior wall surfaces, primarily
stucco. Other mitigation strategies such as protecting roof eaves,
decks and unenclosed underfloor areas with noncombustible materials
are also more common now than prior to 1991.
Another feature that was critical to protecting dwellings from
the firestorms was the more prevalent use of defensible spaces around
individual dwellings or subdivisions. Defensible space is defined
in the IUWIC as “an area either natural or man-made where
materials capable of allowing a fire to spread unchecked has been
treated, cleared or modified to slow the rate and intensity of an
advancing wildfire and to create an area for fire suppression.”
Because of the combustible nature of many of the materials used,
most dwellings constructed in California will burn if directly exposed
to 60 mile-per-hour winds and extreme heat unless fire fighters
are both quick to react and lucky. It is common practice for fire
fighters to triage houses in neighborhoods exposed to fast-moving
wildfires. If a dwelling cannot be protected within fifteen minutes,
a defense is staged at another one that has a better chance of being
saved. As a result, dwellings with the combination of a wood roof
and minimal defensive space will get little aid from fire fighters
unless there are no other dwellings demanding their attention.
 |
 |
 |
| Combustible vegetation and trees like that
surrounding this older San Diego dwelling were a major factor
in property losses. A minimum defensible space of 20 to 100
feet surrounding subdivisions permitted fire service personnel
to save more recently constructed homes. |
The 275-000-acre Cedar Fire that burned into
San Diego suburbs was fueled in large part by dead and dying
trees. |
Old wood shake roofs were responsible for
the loss of many homes in the Scripps Ranch community north
of San Diego. In January 2004, the San Diego City Council banned
the use of wood shingle and wood shake roofs. |
No better example of the significance of defensible space can
be found than in Ventura County, which was spared widespread destruction
even though more than 172,000 acres were burned in the Simi/Val
Verde and Piru fires. Only 37 homes were lost in the county, out
of a total of 3,339 destroyed throughout Southern California during
the October 2003 wildfires. It is important to note that Ventura
County’s brush clearance laws are tougher than most, requiring
homeowners to provide a 100-foot clearance around woodland homes
each spring rather than the state’s minimum 30 feet of clearance.
Ventura’s weed-abatement ordinance is backed by an aggressive
enforcement program that includes sending approximately 14,000 warning
notices to property owners each year. If a property remains in violation
after a second warning, the county contracts for brush clearance
and places an assessment on the owner’s property taxes to
recoup the costs. The program has been very effective, with the
number of homeowners cited for violations dropping each year from
a high of nearly 1,000 in 1991 to just 47 in 2002. During this same
period, yearly assessments dropped from over $1 million in 1991,
to less than $100,000.
Clearly, another critical factor in the preservation of life and
property was the courageous efforts of the many fire fighters who
responded to the emergency. Even with the expertise that comes from
past experience, defending against fires in urban-wildland interface
areas is dangerous and grueling work. Mutual aid among neighboring
fire departments as well as among regions and states is essential
when major disasters like the 2003 firestorms strike, and the effective
mobilization of over 14,000 fire fighters and support personnel
from throughout the region at the height of the blazes cannot be
underestimated.
Conclusion
 |
| Strong, erratic winds in Sand Bernardino drove
wildfire through the Del Rosa neighborhood, destroying some
homes and sparing others. |
 |
There are those who will argue that the October 2003 Southern California
wildfires were in many ways a disaster foretold: that it was a tragic
but predictable consequence of people wanting to live in forests
and brushlands designed by Mother Nature to burn periodically. During
a visit to the three hardest hit areas in Ventura, San Bernardino
and San Diego Counties immediately after the fires’ containment
I found that, contrary to this dire outlook, the vast majority of
newer dwellings in the vicinity of the fires’ boundaries were
still standing. This bears witness to the fact that building and
fire safety officials in the affected areas should be proud of their
efforts to educate the public and elected officials about the high
priority of adopting and enforcing stringent building and associated
wildfire mitigation regulations.
Without the promulgation of standardized provisions like those in
the IUWIC, it would be very difficult to achieve the broad application
of safe and sound practices to protect people and buildings within
our forests and urban-wildland interface areas. Appreciation is
therefore also extended to our national codes and standards writing
bodies and the dedicated people who serve on their committees. Thank
you for a job well done, and keep up the good work!
Click here to read about how
One Home Survived.
Table
1. Summary of IUWIC Fire-Protection Features |
Fire
Protection
Features
|
Description |
| Roof coverings |
Roofs are assigned a minimum roof covering
classification (see Table
2). Spaces at the ends of eaves that allow entry to flames
or embers are to be firestopped. |
| Eaves, fascias and soffits |
Class 1: *Exposed undersides of eaves and
soffits are to be protected by materials approved for a minimum
of one-hour-rated fire-resistive construction. Fascias are required
to be protected on the backside by materials approved for a
minimum of one-hour-rated fire-resistive construction or 2-inch
(51 mm) nominal dimension lumber.
Class 2: *Combustible eaves, fascias and soffits are to be enclosed
with solid materials with a minimum thickness of ¾ inch
(19 mm). No exposed rafter tails are permitted unless constructed
of heavy timber materials. |
| Gutters and downspouts |
Gutters and downspouts are to be constructed
of noncombustible materials. |
| Exterior walls |
Exterior walls of buildings or structures
are to be constructed with materials approved for a minimum
of one-hour-rated fire-resistive construction on the exterior
side or constructed with approved noncombustible materials.
(Heavy timber or log wall construction may also be used.) Such
materials must extend from the top of the foundation to the
underside of the roof sheathing. |
| Unenclosed underfloor areas |
Buildings or structures must have all underfloor
areas enclosed to the ground with exterior walls constructed
as required for “Exterior Walls,” above. Complete
enclosure is not required when the underside of all exposed
floors and all exposed structural columns, beams and supporting
walls are protected as required for one-hour-rated fire-resistive
construction or heavy timber construction. |
| Appendages and projections |
Decks and other unenclosed accessory structures
attached to habitable buildings must be a minimum of one-hour-rated
fire-resistive construction. When any portion of detached structure
projects over a descending slope surface by greater than 10
percent, the area below the structure shall have all underfloor
areas enclosed to within 6 inches (152 mm) of the ground with
exterior wall construction as required for “Exterior Walls,”
above. Complete enclosure is not required when the underside
of all exposed floors and all exposed structural columns, beams
and supporting walls are protected as required for one-hour-rated
fire-resistive construction or heavy timber construction. |
| Window glazing |
Exterior windows, window walls and skylights
are to be of tempered glass or multilayered glazing panels. |
| Exterior doors |
Exterior doors, other than vehicular access
doors to garages, are to be noncombustible or solid core not
less than 1¾ -inch (45 mm) thick. Windows in doors shall
be as required for “Window Glazing,” above. |
| Attic and underfloor vents |
Class 1 and 2: *Attic ventilation
openings, foundation or underfloor vents, or other ventilation
openings in vertical exterior walls and vents through roofs,
shall not exceed 144 square inches (0.0929 m2) each. Such vents
are to be covered with noncombustible corrosion-resistant mesh
with openings not to exceed ¼ inch (6.4 mm).
Class 1, 2 and 3: *Attic ventilation openings are not to be
located in soffits, in eave overhangs, between rafters at eaves
or in other overhang areas. Gable end and dormer vents are to
be located at least 10 feet (3048 mm) from property lines. Underfloor
ventilation openings shall be located as close to grade as practical. |
| Detached accessory structures |
Detached accessory structures located less
than 50 feet (15 240 mm) from a building containing habitable
space must have exterior walls as required for “Exterior
Walls,” above. When any portion of a detached structure
projects over a descending slope surface by greater than 10
percent, the area below the structure shall have all underfloor
areas enclosed to within 6 inches (152 mm) of the ground with
exterior walls constructed as required for “Exterior Walls,”
above. Complete enclosure is not required when the underside
of all exposed floors and all exposed structural columns, beams
and supporting walls are protected as required for one-hour-rated
fire-resistive construction or heavy timber construction. |
| *Class 1, Class 2 or Class 3 ignition-resistant
construction. See Table
2 for details. |
References
- Laura Parker, Tom Kenworthy and Patrick McMahon. “Areas
‘Disaster Waiting to Happen.’” USA Today Nov.
3, 2003: 4A.
- ibid.
Acknowledgments
Recognition is given to the following individuals who contributed
photographs and information for preparation of this article:
Paul Bambauer, Executive Director, Concrete Masonry
Association of California and Nevada, Sacramento, CA
Chris Hastings, Marketing Manager, RCP Block &
Brick Inc, Lemon Grove, California
Elizabeth L. Lile, Cartographer, U. S. Geological
Survey, Denver, Colorado
Craig Morgan, Fire Hazard Reduction Program Manager,
Ventura County, California
Drew Probst, Website Designer/Developer, U. S.
Geological Survey, Lakewood, Colorado
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