Colorado Avalanche Information Center

Pit shows that depth hoar exists at the upper elevations of the treeline zone. While only 5cm thick, it is still the layer of greatest concern and keeps us suspect of steep slopes in this zone. The slab above it is dense and cohesive in this more exposed below treeline location.

Structure and stability tests indicate fair stability and confirm the pattern that east aspects near and above treeline have weak snow near the ground. This location however does not have depth hoar. They are just advanced facets and they are showing signs of rounding. 10cm of 1-2 mm rounding facets is encouraging for future stability.

Some basal facets were visible in parts of the profile walls, but too isolated to include in this diagram. Snowpack tests targeted these areas, but did not produce any results.

Pit highlights depth hoar near the ground. BTL slopes with this structure are not widespread but do exist. As you move lower in elevation areas with this structure are fewer.

Less old weak snow near the ground here than in other locations in the San Juan's is creating greater stability. New slab is not overloading the shallow layer of DH. This location confirms increasing stability in below treeline zone.

Suspect test slope failed after I removed one ski and boot penetrated to ground. Large collapse propagated entire slope back onto 20 deg slope at ridgeline. Stability tests confirmed instability even after slope collapsed. Representative of all NW-N-E aspects near and and above treeline where very weak facets exist at the ground.