Two deadly fires continued to rage in northern California this week, as the state's wildland firefighters battled wind, dry weather, and rough terrain in a desperate effort to protect lives and property. The disastrous fires drew fresh attention to the vulnerability of California's millions of wood-frame houses, many of them exposed to high fire risk conditions in a time of record-setting drought.

With the flames still spreading, it's too early for officials to be looking for lessons learned from this year's crop of wildfires — or even to compile a final tally of the damage. But in previous years, catastrophic wildfires have led to modifications in building practices in California, including the introduction in 2008 of a statewide "Wildland-Urban Interface Code." In April of 2008, JLC profiled one housing development in Southern California that proved the worth of "Firewise" methods by surviving a wildfire with no damage (see: "Surviving Wildfire," by Ted Cushman).

The rough, dry countryside of California's rural counties is a challenging environment for building resilient housing — and also a tough environment for fighting fire. As of Thursday, despite the best efforts of thousands of firefighters on the ground, state fire officials reckoned the tally of the Valley fire at 585 homes destroyed, according to the Lake County News (see: "Cal Fire reports more overnight growth of Valley fire," by Elizabeth Larson). Officials reported two more bodies found in the fire's burn area, raising the death total in that fire to three, according to NBC News (see: "California Wildfires: Two More Bodies Found in Burn Zone of Valley Fire"). Combined with two deaths from the Butte fire in Calaveras County, that brought the week's death toll to five, reported the Sacramento Bee (see: "Retired journalist, composer among five dead in Northern California fires," by Bill Lindelof and Tony Bizjak). Authorities said that the count of destroyed dwellings was likely to rise as damage assessment continues.

Investigators were also working to determine what sparked off the catastrophic fires. Arcing power lines were one likely suspect, the New York Times reported (see: "Fires’ Toll Rises as Power Lines Come Under Scrutiny," by Richard Perez-Pena). "The Pacific Gas and Electric Company said one of its wires might have touched off the Butte Fire; the California Department of Forestry and Fire Protection, known as Cal Fire, confirmed that it was looking into that possibility, among others," the Times reported. "Electricity can arc between a line and another object, like a tree limb, when they touch or come close to each other and drop sparks onto the grass, twigs and leaves below. Conditions were ripe for that kind of ignition when the Butte Fire began last week. Windy weather made trees and power lines sway, the state’s long drought has left the fuel on the ground bone-dry and ready to combust, and the region was experiencing a heat wave."

With conditions so favorable to wildfire, the question of what triggered the fires was almost irrelevant — at some point, a runaway fire was almost inevitable. But one thing is for sure: fighting wildfire is a major industry in California this year. According to the California Department of Forestry and Fire Protection (Cal Fire), 13,000 firefighters are at work in the state currently, battling eight major fires (see: "California Statewide Fire Summary"). Only after the fires are brought under control will authorities gain a full picture of the damage done — and start to learn the lessons. But as California enters what may be a prolonged drought cycle, those lessons are likely to be both significant, and urgent.