Evans Canyon fire balloons to more than 52,000 acres; air quality 'unhealthy for everyone' in Yakima County

YAKIMA COUNTY, Wash. - The Evans Canyon fire just outside of Naches has ballooned to more than 52,000 acres in Yakima County - more than quadrupling in size over 24 hours. 

The fire was still 0 percent contained as of Thursday morning, but emergency management officials say the 440 firefighters working the fire lines have made good progress. 

SR-821 through the Yakima Canyon is closed because of the fire. You'll have to take Interstate 82 instead. 

Air quality in Yakima County is "unhealthy for everyone," and residents are urged to stay indoors as much as possible until the smoke dies down. 

The Washington National Guard has sent in Black Hawk helicopters to assist. 

The fire has destroyed five homes and several other buildings and prompted evacuation orders for hundreds of people. But not everyone is heeding the order to leave. 

RELATED: Hundreds told to evacuate because of Evans Canyon fire, but not everyone is leaving

Officials said the priority Thursday morning is to protect structures, hold the fire lines and complete mop up efforts in extinguished areas.