Wildfires have many causes that vary by region, but most are human induced, while lightning is the main natural ignition source, according to Joseph Mitchell, a physicist and consultant working on power line wildfire issues in California.
Weather can influence how a fire starts, but factors like temperature, wind, and humidity, will affect whether an ignition will lead to a wildfire, Mitchell told Anadolu.
"In California, we have seen large wildfires grow more frequent and destructive over the past three decades," he noted.
Wildfires caused by power lines make up less than 10% of total fire ignitions in California, he added.
"This estimate has varied wildly over the years—down to 1% around 2009—but has solidified around the higher number as better data became available," Mitchell said.
California has multiple independent fire agencies, each with their own data collection strategy, he said. "More recently, Cal Fire has gotten them to report in a consistent manner," Mitchell added.
Additionally, state utility regulators now require utilities to report all fire ignitions from their equipment, which supports fire agency data.
"Major wildfires started by utilities tend to be larger and more destructive than wildfires from other causes. This is because of when they start—during low humidity, high temperatures, and dry vegetation," he said.
"When those conditions are combined with strong winds, the potential for catastrophic fires rises dramatically," Mitchell added.
High winds can bring down power lines, damage equipment, or push branches into wires—all of which can ignite fires under the worst possible conditions, he noted. "Many of California's most deadly and destructive wildfires have been caused by power line ignitions."
While hundreds of utility fire ignitions happen annually in California, most are small and quickly contained.
"The real danger is when these ignitions occur during extreme fire weather," Mitchell said. "The damage and death from such fires far exceed their share of total fire ignitions."
- California's wildifre risk strategy needs better data
"If you don't have good data about power lines or wildfires, it's hard to know where the dangers are—or if your countermeasures are working," Mitchell said.
He stressed the need for fire and government agencies keeping accurate data on all wildfires and their causes. "Specifically collecting data on utility-ignited fires helps identify what needs to be fixed."
Mitchell also highlighted the importance of accurate wildfire risk mapping.
"Scientists need access to landscape, vegetation, climate, and fire history data to model where the risks are now and where they will be in the future," he said. That analysis should be integrated with population data to find areas where large fires would be most damaging.
Old or faulty equipment should be prioritized for replacement, especially in high-risk areas that combine infrastructure hazards, vegetation spread potential, and population density, he said.
"In California, major utilities now favor undergrounding lines, but that's expensive—about $2 million per kilometer," he noted. A cheaper alternative is covered conductor—power lines wrapped in polymer coating to reduce ignition risk.
"California utilities also turn off power during extreme fire weather," Mitchell noted.
"This has proven extremely effective in preventing catastrophic wildfires. But losing power has serious economic consequences and can endanger lives," he stressed.
Doing this well requires utilities to understand both wildfire risk and weather conditions. "Some California utilities even have their own meteorology departments," he said. In places without that capacity, utilities must work closely with weather agencies and develop contingency plans.
"Unusually severe wind events combined with dry conditions are especially dangerous," Mitchell warned.
"That's what happened in Lahaina, Hawaii: extreme winds and dry fuel created a power line firestorm. The same thing happened in Australia in 1983 and 2009, in Southern California in 2003, and in Northern California in 2017 and 2018."
"These events always come as a surprise, but in retrospect, they were preventable," he said.
By Murat Temizer
Anadolu Agency
energy@aa.com.tr