Monday, July 2nd, 2012 9:07 am
By Edward Ortiz
Intense and deeply destructive “super fires,” like Colorado’s current Waldo Canyon Fire, which has claimed two lives and burned 350 homes, are almost assured in Northern California’s future, according to a U.S. Forest Service scientist.
“Typically we’re seeing an earlier fire season and that fire season is lasting longer,” said Malcolm North, plant ecologist with the Pacific Southwest Research Station of the U.S. Forest Service. North works out of the station’s Davis, Calif., office.
The culprits, said North, are weather fluctuations and climate change. He said the warmer temperatures and drier winters seen recently in the region are creating ideal conditions for intense and hard to control fires like the Colorado fire.
“What we’re seeing now is that snow reserves are less in the Sierras and runoff is happening earlier in the year,” he said.
That creates drier conditions in areas where fires burn hottest – the forests. The most difficult to deal with are “crown fires,” whose flames travel from one tree to another, usually at high speed. It is common for crown fires to move at 30 mph, North said.
“Data show that since the 1980s there has been an increase in both the size of fires and acreage of burn, and particularly the burn severity,” he said. “We now know from research that high severity fires, such as crown fires, generally made up 10 to 15 percent of the area of a forest fire. Currently, the average is more like 30 to 35 percent.”
He said drier conditions at lower elevations, such as grasslands, will also lead to more fires, which are vexing because they move fast and burn closer to homes and buildings. These fires will also be seen earlier in the season. Typically, it only takes two weeks after the last rain for grassland plants to dry out and become fire prone, North said.
“We live in a Mediterranean climate, so plants here are adapted to three to four months of drought yearly, but what appears to be happening now is that we’re getting droughts lasting more like five to six months,” he said.
Read the full story on the Miami Herald website.