(CNN) -- Tennessee authorities evacuated more homes near the resort town of Pigeon Forge on Monday as high winds fanned a wildfire that has damaged 35 buildings.
The state declared an emergency and sent in National Guard helicopters Monday in an effort to control the wildfire, which started about 5 p.m. Sunday.
Helicopters were having difficulty dropping water on the poorly contained fire because of the wind, said Dean Flener of the Tennessee Emergency Management Agency.
Authorities were evacuating more residents as the fire threatened 15 to 20 homes in the Priscilla Heights area of Sevier County, Tennessee, according to Flener.
About 150 people were evacuated Sunday and the American Red Cross opened a shelter at the Pigeon Forge Community Center. Hotels are also allowing residents to stay for free, Flener said.
"Propane tanks have been exploding," Pigeon Forge Fire Chief Tony Watson said Sunday. "It's been real dangerous."
About 20 fire departments have been fighting the fire, authorities said.more