SAN FRANCISCO — Devastating California wildfires this year — and expectations of more to come under the extremes of climate change — prompted regulators Thursday to toughen rules for utility companies to keep power lines clear of brush and tree branches that can easily spark into flames.
Public Utilities Commission president Michael Picker called the regulations adopted unanimously by the board “a major rewrite” of the state’s fire-prevention rules for utilities as climate change drives up wildfire risks in much of California.
In a year when the state’s fire season threatens to go year-round, state officials “accept and acknowledge that the scope of the problem is changing,’ Picker said.
The board’s action comes as fire officials look for the causes of wildfires currently burning in Southern California, including a 380-square-mile (980-square-kilometer) fire that has become the fourth-largest in state history. The Los Angeles Times on Thursday quoted a witness as saying she saw arcing power lines throwing sparks at the scene of one of the fires in the San Fernando Valley.
Fire officials also are looking at any role that sparks from wind-whipped power lines played in October’s wildfires in Northern California, which killed 44 people and caused more than $9 billion in property damage, more than any fire recorded in the United States, according to insurance industry figures.
The new state rules for utilities, power lines and vegetation concentrate on areas deemed of higher fire risk. The changes increase the minimum space among power lines and between power lines and vegetation, and speed up timetables for patrols and repairs in areas of higher fire risks.
The agency first began considering the issue after a series of Southern California wildfires in 2007. Those fires were tied to swaying and arcing power lines, some of which fell during heavy winds.
Currently, a redrawing of California’s fire-risk maps is more than doubling the area that officials consider at heightened risk of wildfire, from 31,000 square miles (80,000 square kilometers) to 70,000 square miles (180,000 square kilometers), or 44 percent of the state’s land.
State officials and climate experts point to increasing extremes of weather in California, which last winter swung from five years of drought to near-record rain.
The U.S. Forest Service this week reported a record 129 million trees have perished, raising fire risks, in the state since the drought began. They were killed by hot, arid weather and forest pests that are thriving in the warmer conditions.
Utility companies cooperated with regulators in developing the tougher rules.
“PG&E supports this as a good, next step, and we know there is more to do,” the state’s largest utility, Pacific Gas & Electric Co., said in a statement.