In the case of the Eaton Fire, the investigators are likely to use magnets to help them hunt for the tiny, melted pieces of metal that could have been shed by power lines if they slapped together. But the existence of the metal doesn’t necessarily indicate that’s how the fire started, Nordskog said.

Firefighters began to see some progress battling the blazes on Friday, as the strong winds spreading the flames dissipated somewhat. "These fires are not out, though today we're going to make a lot of progress," California Governor Gavin Newsom, a Democrat, said Friday, the Associated Press reported.