Northern San Juan

You can trigger an avalanche where you find wind-drifted snow forming a cohesive slab over weak snow at upper elevations. Near and above treeline slopes that face northwest to north through east are the most dangerous as strong westerly winds loaded snow onto leeward terrain. Look for and avoid steep slopes that have a lens-shaped or pillowy appearance or slopes that look smooth and sound drummy or hollow. Cracking or collapsing in the drifted snow indicates retreating to lower-angled slopes sheltered from the wind.

Warm temperatures and strong sunshine increase the chances of wet avalanches. Small pinwheels and rollerballs are an early warning sign to move towards shadier terrain. Avoid traveling on or under steep sunny slopes, especially later in the day when warming reaches its peak.

On February 20, a backcountry snowboarder was caught and killed in an avalanche on a terrain feature locally known as The Nose in the Middle Fork of Mineral Creek drainage, west of the town of Silverton. The avalanche occurred near treeline on a northeast-facing slope in the San Juan Mountains. You can read the preliminary accident report here.