01/05/2012 01:19 EST | Updated 03/06/2012 05:12 EST

Ashes from wood stove may have triggered southern Alberta grass fire

FORT MACLEOD, Alta. - Early findings suggest the improper disposal of ashes from a wood-burning stove may have sparked a large grass fire in southern Alberta.

The wind-whipped blaze near Fort Macleod on Wednesday destroyed at least two structures and prompted an evacuation alert before it was brought under control. A flareup overnight burned down a dairy barn.

The major highway in the area had to be closed for several hours because of poor visibility due to smoke. Police also had to deal with several vehicles overturned by winds that gusted up to 100 kilometres an hour.

Cynthia Vizzutti, chief administrator with the Municipal District of Willow Creek, says people need to be extremely careful.

"I can't say strongly enough how important it is that people take every caution possible with regards to ashes, fires, cigarettes, welding," she said Thursday. "The fire hazard here is extremely high, probably the highest we've seen it in a decade."

An Environment Canada wind warning for the area ended Thursday morning, but unseasonably warm, dry conditions were expected to continue.

At least two other grass fires swept through southern Alberta on Wednesday.

A downed power line sparked a blaze that ravaged a 60-square-kilometre area and destroyed or heavily damaged five homes near Nanton. RCMP said at least seven outbuildings and several vehicles were also charred by the flames.

One woman was taken to hospital and treated for breathing difficulties.

Another blaze near Walsh in the province's southeast burned through fields and grassland. An official from Saskatchewan's fire safety branch said the flames did not cross the boundary into that province as earlier believed.