Quick report
- Collapsing
- isolated
Triggering an avalanche is most likely at upper elevations and middle elevation W-N-E facing slopes where slabs rest atop weak facets and facet + crust combos near the ground. Snow cover is sufficient to create a weak layer at the surface once snow returns.
We experienced a couple of small (~10' diameter) collapses on low-angle SE-facing slopes around 8,800'-9,000'.Weather
- Cloud Cover
- scattered
- Wind Loading
- none
- Recent Snowfall
- ~1-3 cm
- Snow Avail For Transport
- small smounts
Moody low and mid-level clouds hung in the Boulders and Smokys. It cleared to mostly blue skies in the southern Sawtooths, Smokys, Boulders, and White Clouds sometime mid-morning. Cloud cover increased again in the White Clouds around noon. There was a small band of snowfall followed by clearing and another wave of snowfall around 3 PM. No appreciable precip by 3 PM. There were darker clouds and snow showers over the Sawtooths as we exited the field.
Snowpack
Our main objective was to get eyes on a portion of the zone where we have not traveled yet this season. About an inch of new snow sat atop isolated pockets of SH, faceted snow (shaded), and a soft, moist, soon-to-be crust (sunnier slopes).
Snow depths were 35-65 cm in shaded, sheltered middle elevation terrain (7,500-9,500') and 25-35 cm on steeper, sunnier slopes. We found a welded ice crust at the ground coupled with large facets on SW and SE-facing slopes above about 9,000'. This poor structure propagated small collapses where a crust helped tie the thin slab together. This seemed consistent with collapses and poor structure noted by Ben and Brooke in similar terrain out 4th of July Ck on (12/14).
Avalanche
We did not observe any recent avalanches. We had good visibility, but signs of avalanche activity since 12/6 would have been hard to spot with previous light snowfall and drifting-in of crowns. We came across one D1.5 likely from around (12/6) on a NE-facing slope at 9,200'. Snowpack tests were performed adjacent to the crown (see below).