HELENA, Mont. (AP) — Glacier National Park officials say work has begun to reconstruct a backcountry dormitory that burned in a fire last year.

The work to rebuild the Sperry Chalet got underway Monday after trail crews cleared thousands of trees that fell during last year's lightning-caused fire that destroyed the century-old chalet.

Hikers will have to yield to pack mules hauling supplies up the popular trail to the construction site. Helicopters also will be used in the reconstruction, which is expected to be completed in fall 2019.

The first phase will last until October and includes stabilizing the structure, framing the roof and building interior walls and floors.

The park service has set aside $12 million for construction. Insurance is expected to pay $1.2 million next year.