Smoke from wildfires is causing airline flights to be delayed or canceled in Northern California.
More than 80 flights were canceled by late Thursday morning at San Francisco International Airport, said airport spokesman Doug Yakel.
He says delays on other flights average 30 to 45 minutes. The Federal Aviation Administration says some arriving flights are delayed more than three hours.
Several flights are canceled at Charles M. Shulz Sonoma County Airport in Santa Rosa, near the epicenter of fires in the wine country. Airport director Jon Stout says United and Alaska each plan a flight later, and a Sun Country flight is expected if smoke is not too bad.
Wildfires have killed at least 23 people and destroyed more than 3,500 homes and businesses north of San Francisco.