CARPENTER ANTS are a serious structural pest that should be addressed immediately. Moisture problems/leakage from pipes, roofs, etc, attract them to nest. These areas include doorways, window sills, floorboards and rafters. As they chew and excavate their galleries, they will compromise the integrity of your structure. They leave piles of debris, frass-wood and insulation. This is why they are called carpenter ants.
TERMITES do live in Montana. They have been found in Missoula and Ravalli counties. Termites come from underground. They consume the wood and build tubes with their excretions to tunnel from the ground to the wood in a structure. The tubes also protect them from the drying air. They can do extensive damage.