Wildfire at the Backdoor
As Americans move closer to the wildland, wildfire risks increase
At least 20 major fires are currently burning or burned this year in California
(see lower left for legend)
and at least 10 in neighboring Oregon
So far this season, burned area totals over 7.7 million acres nationwide.
Trends suggest larger, more intense fires:
Over the last three decades, the annual acreage burned has increased,
While the number of fires has decreased.
Suppression costs have skyrocketed:
Over the last ten years, suppression costs averaged nearly 2 billion dollars a year
The last five years cost 60% more than the prior five-year period
Not all fires pose the same risks:
One factor influencing suppression costs is where wildfires are taking place.
Historical fire patterns show numerous fires along the west coast.
Over that period, large fires were concentrated in the intermountain west, ranging from the Sierras to the Rockies, and along the Pacific coast.
In many of these areas, fire is a natural and even essential ecological phenomenon.
Wildfires can be segregated by ignition cause:
Lightning strikes are the dominant cause of wildfire ignitions in the intermountain west.
However, human-caused ignitions are the dominant cause of wildfires along the Pacific coast.
Wildfire ignitions occur in areas of low and high population density.
However, human ignitions occur more often at the outskirts of population centers, like the Bay Area.
Whereas natural ignitions occur in rural intermountain areas, including areas dominated by federal lands.
Human ignitions often occur in the WUI:
Development in urban and suburban fringes over the last three decades has increased the risk of human ignitions in the wildland-urban interface.
Wildland-urban interface (WUI): the area where human made structures and infrastructure are in or adjacent to areas prone to wildfire
Over 11 million people, or thirty percent of California's population lives in the WUI.
As of 1990, California was already highly developed with over 8 million people living in the WUI.
Between 1990 and 2010, the number of Californians living in the WUI increased 36% and WUI land area increased nearly 20%.
Over 775,000 homes are at extreme risk of wildfire damage in the western US.
Areas where fire occurrence and population density are correlated include counties near and around urban areas.
WUI occupies these suburban, fire-prone areas.
WUI areas are adjacent to, or even overlap historical fire perimeters.
Human impacts are expensive:
Human-caused fires account for 1/3 of all firefighting costs.
1/2 of firefighting suppression goes towards protecting houses.
Across the west coast, preparing for the future means preparing for wildfire.
There is an undeniable and staggering impact of climate change. Climate change promises to increase the severity and unpredictability of our future fire seasons. It's multipronged impacts include denormalization of seasonal conditions, like rising average temperatures, prolonged periods of drought and changing rain and snow patterns, shifting plant communities, and increased human pressures on the environment.
However, strategies for managing coexistence with fire must consider our role in exacerbating wildfire seasons through our habitation close to nature and our propensity to cause fires directly (e.g. campfire, fireworks) or indirectly (e.g. powerlines, trains).
