Authorities suspect a spark generated by a hay mower hitting a rock caused a 200- to 300-acre grassfire Monday about six miles southwest of Wing.

A path of charred earth snaked across miles of pasture land and stubble fields, narrowly missing several stacks of hay bales. The nearest structures were more than two miles away.

"There wasn't any buildings in danger at all," Wing Fire Chief Dale Olson said.

The Wing and Wilton Fire Departments responded at 2:30 p.m., each with two brush trucks and a tanker truck. Nearby farmers used tractors with field cultivators to churn earth around the edges of the fire to slow the flames and give firefighters time to stop them.

"I thought it was going to get away from us there," Olson said. "It was moving across that stubble field pretty fast."

The fire was contained by 5 p.m. Area farmers will monitor the smoldering area overnight, Olson said.

Although it's late in the year, Olson said he hasn't let his guard down.

"We expect fires any time it's dry," he said. "There isn't a time we don't expect it."

Wilton Fire Chief J.D. Youngbird said his crew also fought a one-acre grassfire Monday afternoon near Baldwin.

(Reach reporter Mike Albrecht at 250-8261 or cops@ndonline.com.)