Over the weekend, the windswept Lost Horse Fire in the Darby Ranger District has increased in size to over 40 acres, and is considered zero percent contained.

Bitterroot National Forest spokesman Tod McKay said on Sunday that the lightning-caused fire is burning in rugged terrain too inaccessible and dangerous for fire crews, so it is being fought from the air.

"On Saturday, our three helicopters dropped 72,900 gallons of water on the fire," McKay said. "Also on Saturday, our fixed wing aircraft dropped over 4,000 gallons of retardant on the fire. It's really been a constant aerial assault on the fire, due to where it's located, that's all we can get to the fire."

McKay said the fire is burning about 10 miles southwest of Hamilton, and is not threatening any structures, roads or trails. Officials will keep a close eye on the fire and send more crews if necessary.

Bitterroot National Forest Spokesman Tod McKay