The fires have swept through more than 39,000 acres so far. Officials report that at least 16 people have died.

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.

Massive fires continue burning after igniting in the foothills of Pacific Palisades, and Altadena, forcing thousands to evacuate amid a life-threatening and destructive windstorm slamming Southern California.