The municipal district of Bighorn declared a local state of emergency Tuesday after overnight winds pushed a wildfire within 20 kilometres of the hamlet of Benchlands, while expanding the perimeter of the fire from 600 up to 3600 hectares.

As the wildfire blazed out of control near Blackrock Mountain, people living nearby said they're seeing signs that it's spreading.

Rancher Pat Brennan said, "There was some ash on the cattle when they came in for their water this morning."

Benchlands resident Jeff Gotta added, "The plume was massive. It worried some people and we need to get that message out."

Another Benchlands resident, Margot McMechan, said, "You could see that the fire looked out of control...and then this morning, we all got phone calls at like 6 a.m."

All of that was enough for the reeve of Big Horn, Dene Cooper.

"Under these conditions of dryness, this is really rough," Cooper said.  "Everything that forestry can do is being applied to this situation."

The road to Ghost River was closed while fire crews battled the blaze. 23 firefighters tackled the east flank, with six helicopters bucketing water. One heavy equipment group was standing by in case a protective berm was needed.

The wildfire started in the forest reserve at Devil's Head back on September 4, when a campfire was left unattended - something residents say happens too often.

"We've seen campfires from random campers left burning unattended," said McMechan.

The wildfire is not threatening any structures and has not led to any evacuations, but nearby residents are advised to be ready for a last-minute leave if necessary.

"It makes us extremely nervous," said Benchlands resident Janice Anderson. "I've got three dogs at home and it makes you think about what I need to do, where's my important paperwork, my husband works from home, what do I need to get?"