The California Highway Patrol had to escort vehicles in small batches through the smoky section of road Tuesday at the base of the Grapevine near Fort Tejon. Another fire burned about 80 acres of wheat fields along southbound I-5 north of Highway 166.
Major fires have already burned nearly 50,000 acres since Sept. 8, when they were sparked by lightning strikes. Low humidity and brisk winds have made it difficult for firefighters to contain the blaze.
Fire danger is also high in Indiana, Illinois and Kentucky.