As blazes continue around San Diego, can humans do more to prevent future fires?
Investigators around San Diego continue searching for the causes of ten fires that burned thousands of acres of land in the area this week, after determining that one of the blazes was set by sparks from construction equipment.
Whether the other blazes were set intentionally or by accident, experts say it's highly likely that humans are to blame. Two people were arrested north of San Diego on Thursday on suspicion of arson, though it's not clear if they are thought to be connected to this week's big fires.
Unlike remote parts of the world where natural events like lightning strikes are prime sources of wildfires, in southern California, such fires are almost always started by people. Ninety-five percent have a human cause, according to Cal Fire, the state's firefighting agency.
The situation may worsen in the face of expected population growth. Metropolitan San Diego's population is expected to reach nearly 4.5 million by 2050, over a million more than today. (Pictures: San Diego Wildfires)
"The probability of fires is increasing because people are increasing," said the U.S. Geological Survey's Jon Keeley, who has spent years studying the history of California wildfires.
The Wildest Things
Most of the big Southern California wildfires of recent years were found to have human causes.
In 2007 a fallen power line near San Diego set off a fire that scorched nearly 200,000 acres and killed two people.
In 2009, sparks from a weed cutter are thought to have led to an 8,700 acre fire in Santa Barbara County that torched 80 homes.
And earlier this month, an illegal campfire started in Rancho Cucamonga grew to 2,700 acres.
Other area fires have been blamed on chains dragging behind cars and throwing off sparks, smoldering cigarette butts, welding tools, errant gunfire, and arsonists.
"It's anything you could possibly think of," said Alexandra Syphard, a San Diego scientist at the non-profit Conservation Biology Institute who has combed through thousands of California wildfire reports to understand what's causing the fires. "You see the wildest things. One of them was a satanic ritual."
A more common culprit: outdoor equipment, from power saws to lawnmowers. Power tools accounted for more than 20 percent of fires in San Diego County between 2000 and 2010. That was followed by fires caused by campfires (nearly 10 percent), arson (roughly 5 percent), trash burning (around 4 percent), vehicles doing things like sending out sparks or igniting vegetation with overheated tailpipes, downed or malfunctioning power lines, kids playing with fire, and cigarettes.
Blackouts and Leapfrog Housing
Some fire experts see a silver lining to these dreary statistics: If people are mostly to blame for wildfires, they can do something about it.
"Weather doesn't cause fires–weather just causes a fire to burn," said Cal Fire spokesman Daniel Berlant. "It's the people that have the role of actually preventing that fire."
His agency, along with the U.S. Forest Service, the National Park Service and other land managers that deal with wildfires, is leading a public relations campaign urging Californians to reform outdoor habits.
Written By: Warren Cornwall
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