The Lost Horse Fire 10 miles southwest of Hamilton, Montana is an interesting study in wildland fire behavior and fire suppression tactics. The 40-acre fire is burning in boulder and rock scree fields where the primary method of spreading is through spotting — burning embers traveling hundreds of feet or more and starting new fires in receptive fuels. Some of the patches of vegetation appear to be an acre or more, but most of them are small. The fire is burning on very steep terrain. That fact and the large bounders make it very difficult for firefighters to even walk around in the fire area.
On Saturday three helicopters dropped 72,900 gallons of water on the fire. A large air tanker dropped more than 4,000 gallons of fire retardant on the ridge to try and keep the fire from moving further north.
If you are used to building a fireline to suppress fires, this one already has “firelines” pretty much everywhere — the boulder and rock scree fields that comprise more of the area than the vegetation does.
There is no place for a helicopter to land in the boulders. Rappellers have said they could rappel into the area but there is not much they could do once they are on the ground. So far the only attack has been from helicopters and an air tanker.
Looking at the video below and images from Google Earth, there is more continuous vegetation on the ridge and on the north side, but trying to build fireline where trees grow out of crevices between large rocks would be difficult.
This might be the classic case of needing to back off and find a place from which a burnout could occur, or just try to cool it off from the air to reduce torching and spotting — apparently what they are doing now. If they do nothing but monitor it, it might run out of fuel in a while, or it could be a real pain in the ass for the next four to eight weeks of fire season.
You can keep up with the fire on InciWeb and Facebook.