Sometimes it's hard for them to trace a fire back, but they eventually do. I'm assuming it's because they all seem to have different sources? But it does seem like we're having an abnormal amount of fires lately, and it's not even summer time when they're usually worse.

One of the California fires was started from a semi driving down the highway that produced a spark that happened to catch the grass on fire, and it was so dry and they don't do any forest maintenance, so it quickly spread.

I thought South Carolina was more of a swamp, though, and it would be harder for a fire to spread so quickly?

I don't have a sauce with the video, but from previous fires, they had satellite videos and caught arsonists coordinating efforts by starting multiple fires across a large area. These small fires ended up combining into one giant fire. I can't remember if that was near Canada or California, but it was somewhere on the west coast. I think it was this one: https://www.the-sun.com/news/1461447/four-arrested-intentionally-starting-blazes-wildfires/