Firefighters worked to contain huge blazes in the northwestern US city of Spokane early Monday after officials reported hundreds of structures had been reduced to cinders. Smoke accumulating over the city would likely render air quality "very unhealthy" on Monday, the regional clear air agency said. Fire officials warned that "unauthorized" drone incursions into restricted airspace above wildfires were forcing the grounding of helicopters and other aircraft fighting the blazes. The biggest of the three fires burning in Spokane, the Old Trails fire, jumped the Spokane River on Saturday afternoon and crossed into the city proper. She got stuck in traffic has she tried to flee as the fast-moving fires blocked routes out of the city.