We have to learn to live with fire. by Bill Gabbert 2019
A
reporter asked me what needs to be done to keep from repeating
disasters like we have seen recently in California at Paradise, Redding,
and the Napa Valley. I told him that there is no one thing that needs
to be done, such as raking or “forest management”, it requires a
comprehensive holistic approach.
The principle of the weakest link
in the chain applies here. If one of the categories of improvements to
protect a development is sub-par, the individual structures and the
entire community in a fire-prone environment is at risk. And if a
homeowner does not do their part, it can endanger their neighbors.
Reducing
the chances that a fire in a populated area will turn into a disaster
that burns thousands of homes involves at least five categories of
factors: home spacing, envelope of the structure itself, home ignition
zone, community infrastructure, and the wildland urban interface. Home spacing/lot size
Cities,
counties, and planning boards are often under pressure to approve new
housing developments. They want to expand their tax base. Developers try
to fit as many homes into a new subdivision as possible to maximize
their investment. This too often results in homes that are 20-feet
apart. If one is ignited by a burning ember that may have traveled a
quarter of a mile from a fire (or a burning home) the radiant heat alone
can ignite the homes on both sides. Then you can have a self-powered
conflagration spreading house to house through a city. When the
structures are that close together, the homeowners have not reduced the
fuel in the Home Ignition Zone, and the home itself is not built to
FireWise standards, a massive disaster can be the result.
If a
homeowner wants, or is required, to reduce the flammable material within
100 feet of their residence, what are they expected to do if there is
another home 20 feet away that is really a large assembly of flammable
material?
A
neighborhood on Debbie Lane in Paradise, California, before and after
the Camp Fire that started November 8, 2018. The homes were 14 to 18
feet apart.Some of the homes in Paradise,
California that burned were less than 20 feet apart. According to
measurements using Google Earth, we determined that the structures in
the photo above were 14 to 18 feet from each other.
The National Institute of Standards and Technology released a report on the 2012 Waldo Canyon Fire
that burned 344 homes and killed two people in Colorado Springs,
Colorado. They concluded that current concepts of defensible space did
not account for hazards of burning primary structures, hazards presented
by embers, and the hazards outside of the home ignition zone. In
addition, NIST recommended:
High-density
structure-to-structure spacing in a community should be identified and
considered in [Wildland Urban Interface] fire response plans. In the
Waldo Canyon fire, the majority of homes destroyed were ignited by fire
and embers coming from other nearby residences already on fire. Based on
this observation, the researchers concluded that structure spatial
arrangements in a community must be a major consideration when planning
for WUI fires.
After studying the Carr Fire that
destroyed 1,079 residences at Redding, California earlier this year,
retired CAL FIRE Battalion Chief Royal Burnett reached similar
conclusions.
It was easy to figure out why the houses
on the rim burned — they were looking right down the barrel of a
blowtorch. Even though they had fire resistant construction, many had
loaded their patios with flammable lawn furniture, tiki bars and
flammable ornamental plants. Palm trees became flaming pillars, shredded
bark became the fuse, junipers became napalm bombs. Under current
standards houses are build 6 to an acre; 10 feet to the property line
and only 20 feet between houses. Once one house ignited, radiant heat
could easily torch the next one.
Envelope of the structure itself
Included
in this category are characteristics of the roof, vents, siding, doors,
windows, foundation, fences, eaves, and decks. A FEMA publication (13 MB) has excellent detailed recommendations. Headwaters Economics found that the cost of building a fire-resistant home is about the same as a standard home. When implemented, Chapter 7A of the California Building Code, regulates these features. Home Ignition Zone
The NFPA and FireWise
programs recommend reducing flammable material within 100 feet of
structures and spacing trees at least 18 feet apart that are within 30
feet of the home. At the 60 to 100-foot distance tree canopies should be
at least 6 feet apart. Another house that is 15 to 50 feet away is also
fuel, and if it ignites will be a serious threat.
Firewise vegetation clearance recommendations. NFPA.Community infrastructure and planning
Road and driveway width, wide enough for large fire trucks
Turnarounds at the end of roads
Signage, and
Emergency water supply.
Again, the FEMA document has great recommendations. Wildland-Urban Interface
There
is of course much that can be done surrounding the places where people
live that would reduce the vegetation or fuel and decrease the intensity
and ember generation potential of a fire as it approaches an urban
area. Large scale fuel management projects including fuel breaks and
prescribed fire programs are usually conducted by state and federal
agencies.
Fuel breaks at Silverthorne, Colorado during the 2018 Buffalo Mountain Fire. USFS.A
fuel break does not have to be devoid of vegetation, but it should have
minimal tons per acre that would therefore burn with less intensity and
with fewer fire brands being lofted downwind. This could enable
firefighters to make a stand and create a place from which to ignite a
backfire, perhaps aided by aircraft dropping water or retardant. Fire codes are essential
The
only effective way to ensure that residents understand and implement
these tasks is to make them mandatory by establishing Fire Codes at the
local and state levels. Analysts studying the aftermath of the Camp Fire
which destroyed much of Paradise, California found that homes built to
fire-safe standards had a much higher survival rate than those that were
not. Beginning in 2008 new construction in the city was required to
follow a standard, Chapter 7A of the California Building Code,
designed for the state’s areas at high risk from wildfire. Fifty-one
percent of the homes built under the 7A code survived, while only
eighteen percent built before 2008 did.
Chapter 7A lays out
standards for roofs, exterior walls, vents in exterior walls and attics,
windows, exterior doors, decking, and outbuildings. Remember, the cost
of building a fire-resistant home is about the same as a standard home.
The
warming climate is demonstrating that wildfires are becoming
increasingly perilous. It is the responsibility of state and local
governments protect their citizens by enacting sensible standards.
Great advice Bill.
What can be done quickly?We can't rebuild vulnerable towns overnight.
Every town and everybody should have a plan for escape to a Safety Zone.
Evacuation planning should include the chance that cell phone and internet service
will be out.
Fire sirens/air raid sirens carry for miles. Link
Safety Zones should be designated. Some could be schools with large sports fields and others, areas with lots of parking.
Fire behavior is increasing and with wind events fires are growing at alarming rates.
All people and all families need to be ready to quickly escape to a Safety Zone.
A place they will be safe if the fire does it's worst.
Lessons from the Camp Fire
as reported by the Butte County grand Jury page 37
