No, it isn't normal, but then neither was the recent,
so-called Angora fire, on the south side of Lake Tahoe. It rampaged
through housing tracts and burned (I've read) 254 homes. Apparently
there were a lot of dead trees from bug infestation and drought (this
year.) Pine trees tend to be very pitchy, too, and very
flammable.
Barbara
I'll retract my former statement, after I read
it. A catastrophic forest fire is not always common, but closing an area,
and therefore an event, IS fairly normal for the CalFire Dept. We almost
had to cancel Swanton Pacific one year because of a small but potentially deadly
fire on a ridge about a mile from our trail. Forest fires are responsive
to wind change and can blow up into an inferno very quickly.