September 1, 2007 Foresters and geographers have mapped the locations in the Santa Monica mountains where the most destructive fires are likely to start. To make their map, they combined data about where fires were likely to start with where conditions make fires likely to spread. The work has spotlighted the areas where limited resources can be focused to have the most effect in stopping the most damaging forest fires from starting.
They burn, strip away and destroy everything in their path. More than 140,000 wildfires occur each year in this country, costing us billions. And the problem is getting worse. Now, scientists are figuring out where wildfires will happen before they happen.
"We were so lucky to get out. Another 30 seconds and we probably would not have been able to get out," Roth said. She lives in a wildfire's paradise -- dry vegetation and medium density housing where communities meet the country. Scientists call it the "Wildland-Urban-Interface."
"Things are changing now, and so the fire season's becoming longer, fires are becoming more frequent. They're becoming larger," said Alexandra Syphard, a fire ecologist at the University of Wisconsin.
That's why Syphard is dedicating her life to figuring out where they'll happen before they happen. The recipe for disaster? Dry, flammable vegetation, a mountainous region and the Wildland-Urban-Interface. It's become a desirable place to live because people are removed from the cities. "In California as a whole, 95 percent of the fires are caused by humans," Syphard said.
It can be just throwing out a cigarette, or...
"Even a car backfiring can produce a fire in this really dry vegetation," Syphard said.
Syphard plugs in these human factors to show where wildfires will strike and spread.
"These really high hazard areas then would be good places to focus treatments," Syphard explains.
She said the best tactic is to cut down on urban sprawl, because once fires start, they're almost impossible to stop. It's the human factors that make fires start and the environmental factors that make them spread. And important to remember, although southern California is one of the biggest danger zones, fires can happen anywhere.
The American Geophysical Union contributed to the information contained in the TV portion of this report.
BACKGROUND: The Santa Monica Mountain Range, located just north of Los Angeles, is one of the most fire-prone regions in Southern California. To help fire managers identify the best locations for site treatments in that region, a University of Wisconsin, Madison team of scientists developed a map that incorporates both environmental and human factors to pinpoint where the most devastating wildfires are likely to start.
MODEL BEHAVIOR: In collaboration with the US Forest Service's Northern Research Station in Evanston, Illinois, the researchers generated computer models based on a variety of data for the Santa Monica Mountain region, including what starts fires, and how much area is burned by fires, as well as the locations of homes, roads, trails, local climate, and terrain. They found that the vast majority of wildfires begin near human infrastructure or along roads that serve as an interface between wild land and urban areas. However, the area burned by a fire depends more on such factors as the type of terrain, climate or vegetation. By combining the data on where fires are likely to start with where fires are most likely to spread, the UWM researchers were able to map out areas where the most destructive fires are likely to start.
RUNNING WILD: Weather is a key factor in starting and spreading wildfires -- particularly drought, which dries out vegetation. Trees, underbrush, dry grassy fields, pine needles, dry leaves and twigs can all cause and spread forest fires because they burn faster, like kindling, than large logs or stumps. The more fuel that is present, the more intensely the fire will burn and the faster it will spread. When the fuel is very dry, such as after a long drought, it is consumed much faster, and the fire is much more difficult to contain. As the fire spreads, it generates heat that evaporates the moisture in potential fuel materials just beyond it, making it easier for those to ignite. Wind can also help spread a forest fire, and is the most unpredictable factor. Winds supply the fire with extra oxygen and push it across the land at a faster rate. Because the wind generally flows uphill, fires also travel faster up a slope than downhill. Wildfires can even generate their own winds, called fire whirls, which resemble tornados. They arise from the vortices created by the fire's heat, and can be so strong they have been known to hurl flaming logs and burning debris over long distances.