and the fire raced through the canyon. within minutes it gained a 32 acre foot hold on the north side of the highway and prompted more evacuations. officials expect more today it. >> low humidity and fuel moistures are critical. they are low and the aspect and ignition source and all of them come together like a perfect storm and the fire takes off on you. >> that's what we have here. >> reporter: given the rugged terrain much of the four fight is an air assault. tankers and choppers are dropping flame retardant. and that will buy time for the courthouse on the ground. they have more than 20 other active wildfires in the state.