Tuesday's report, too rapid for peer-review yet, found global warming boosted the likelihood of high fire weather conditions in this month's fires by 35% and its intensity by 6%.

With parts of Los Angeles County still smoldering from wildfires, the expected rain this weekend would seem like a welcome relief. But how the rain falls could make the difference between a disaster respite or a disaster repeat.

Officials cautioned that ash in recent burn zones was a toxic mix of incinerated cars, electronics, batteries, building materials, paints, furniture and other household items.