Following your image URL

https://www.nasa.gov/feature/goddard...lifornia-fires

Damn!

The Tubb's fire (the one that hit Santa Rosa) is the deadliest fire in California history. Idk when it comes to size but I think the largest ever was in 2012.

What is this due to? Is the weather so hot and dry there, even now in the depths of winter? Or is there some human agency at work?

The depths of winter? It's only October. I don't know the details of these particular fires, but California is a pretty dry state in general so it's prone to forest fires. Sometimes they're caused by human activity, sometimes they're caused by natural events.

What don't you understand? It's October. It's winter. It's cold. Is it not so in Californ-eye-ay?

I guess you have to live in Ireland, to see the rain pissing down and how cold and miserable it is, to feel like you're in winter already. DST at the end of this month will plunge us into darkest night by 6:30 pm. Sure feels like winter to me!

It is fall. It is fall all around the northern hemisphere. It will not be winter until December 21.

We had a lot of rains at the end of last year and the beginning of this year which caused an increase in vegetation. Drought conditions made that all dry out and die. Then we had the fast and dry Santa Ana winds come through and it was a recipe for disaster. I had a friend in Eureka whose wife couldn't leave the house because the winds literally knocked her down when the Santa Anas started a couple of weeks ago.

It's too early to tell if it's arson. My money is on natural causes/accidents.

Also California winters are pretty tame.

Global warming and encroaching human population. Pre-endless-urban-sprawl periodic lightning strikes would burn portions of the forests enriching the soil with nutrients like nitrogen. Now people try to contain wild fires while maintaining the ecosystem with controlled burns. But it's not nice to try to fool Mother Nature.