Enjoy Glacier’s winter landscape, but take into account your skiing ability, and check with rangers for local weather and snow conditions. Severe weather, lack of snow, winter rains, or melting conditions can quickly alter the difficulty of any winter trip. Most ski routes are not marked. A topographic map will help. Plan to break trail on less popular routes. The Middle and North Forks of the Flathead River present major barriers to travel on the west side of the park. Skiing on frozen lakes is dangerous and not recommended. Skiers, snowshoers, and hikers are asked to maintain separate tracks and register at the trailhead registration boxes. Climbers should complete the Voluntary Climber's Registration form, available at ranger stations, Park Headquarters, and the Apgar Visitor Center.