I've gone through the area a couple of times. I'm also following the progress of the American fire, in a really beautiful backcountry area and a shame.
There are a number of recent fires that are suspicious. Whenever one is first detected on a weekend, I figure a camper might have had a fire in spite of the restrictions, or dropped a cigarette. Recent fires that have first been detected on the weekend are a fire near Sly Park lake a few weeks ago, one by Volcano on the same day, the American fire, the Bridges fire in Calaveras (I think by the hiking trail to the Natural Bridges, probably a hiker started it) In any case, there was no lightning activity around the time any of these started.
KLR688, DL650, XL1200