Quick report
- Cracking
- isolated
Alaska Avalanche School Level 1 did three separate mini-tours for the snowpack day. With high winds forecasted, we kept to the mid to lower upper terrain; all obs were below 4,000'. A. Cross Hill, B. Eldorado Test Slope and C. Marmot NW.
We saw upside down structure with ~5" of fist hard, soft new storm snow with minimal to no wind effect over stout pencil hard slabs to be present and easy to find on SW-NE terrain. This is all sitting over various facet/crust layers which are on top of well-developed basal facets. This structure seems to be poorly adjusting to modest new loads as evidenced by our tests.
The Cross Hill tour saw a 1m shooting crack in the same SW location they got propagation in pits on the 27cm down facet layer. Outside of this, we saw no surface level signs of instability, whumphing or recent natural avalanches. Note that we saw no other parties uptracking or skiing terrain in the greater IM basin.Weather
- Air Temp
- 28
- Cloud Cover
- overcast
- Wind Loading
- previous
- Recent Snowfall
- 5"
- Snow Avail For Transport
- moderate amounts
Skies were mostly overcast though intermittently broken. Cloud ceilings were high above ridgetops and we were able to see most terrain. We experienced a 20 minute fog bank that quickly moved up valley and dissapeared around 1pm. There was momentary pluming when we arrived at the pass at 4068 though we did not see any other signs of winds. In our locations, winds remained light out of the southeast. By 3pm, we experienced some momentary trace snowfall that quickly subsided as the valley became overcast again. It was not snowing when we left the field and winds remained light at mid and low elevations.
Snowpack
A. Cross Hill 3,900 SW HS80 saw failure on isolation (CTV) and ECTP5, 27cm down. In student pits, they got results at the two separate facet layers (see photo) The same team also dug on windward aspects (SE) and saw less notable results (ECTN).
B. Eldorado 3,200 NW 26* HS122 also saw failure on isolation (ECTPV) and subsequently propagation in pits from the elbow on all 4 ECT tests. This either failed on facets directly below the pencil hard 1/6-1/7 hard slab (ECTP19, PST 50/100 END below the 1/6-1/7 slab 75cm down) or on the top of basal facets (see pit wall markup). CT12RP and ECTP21 on basal facets 86cm down. Watch the videos.
C. Marmot NW 3,300. No notable results here though structure was the same as the two other locations; new snow over pencil hard slab over various facet/crusts and basal facets.