Fire crews hose down hotspots Thursday in the fire near Opal, Alta. Fire crews hose down hotspots Thursday in the fire near Opal, Alta. (John Archer/CBC News)A wildfire near Opal, Alta., that destroyed one home and burned 30 square kilometres was likely sparked by an all-terrain vehicle in the area on May 12, Thorhild County officials announced Thursday.

"I'm very disappointed that people ignored the dry weather conditions and caused a major wildfire that resulted in the loss of a family's home and other properties, forced many people to evacuate and cost millions of dollars to control and extinguish," Thorhild County Reeve Charles Newell said in a news release.

The fire 60 kilometres north of Edmonton is still burning but is considered "held," meaning crews are able to keep it from spreading outside a perimeter.

Wet weather over the past two days has helped firefighters get control over the fire, which at one point was burning out of control due to hot, windy conditions.

However, Newell warned that despite the rain, the area is still very dry and he asked that people use "extreme caution" with ATVs because they could start a fire.

About 209 firefighters from Alberta Sustainable Resource Development are at the scene. An additional 80 firefighters are expected to arrive on Thursday.