Observation: Public

Observation Details

Triggered Avalanches

Observed Avalanches

Signs of Unstable Snow

Observations

Traveled up Henry Cr from Berne, leaving car at 0830 under partly cloudy skies and temps hovering around 30. Easy and efficient travel through the clear cuts and the flats around the 4k level in Henry Cr. Ascended E facing slopes into xmas tree runout below the main Jim Hill bowl. Ski crampons were found to be helpful (though not mandatory) in this section as the underlying MLK crust was slick on the skins as slope angle steepened. Recent avalanche debris from last weekend observed in this area as above.

We gained the ridge via sparse trees, topping out at 6331' under broken skies with mildly wind stiffened snow at and just below lee aspects on the ridgeline. We descended low angle open terrain for 200' and then cut east to avoid a steep wind affected roller. We found non-wind affected snow in this location and committed to skiing a mid 30 degrees slope one at at time. This was the location where the above mentioned skier triggered hard slab occurred, failing on the 1/4 layer. From here, we descended into trees down to the flats/clear cuts and out to the car. Of note, surface conditions in the old growth forest below 5k were sporting.

As a reflection on my approach to the day- following a warm-up/rain event and cooling with moderate snowfall and wind, I was focused on assessing for and avoiding wind loaded slopes, with less of a mind paid to deeper instabilities in the snowpack, in particular given our agreed upon plan of avoiding planar, open, ATL slopes. I was thus quite surprised when our party's relatively conservative travel plan resulted in an unintentional skier triggered avalanche- once again a prime example of inherently risky and difficult to predict spatial variability. This risk continues to humble me and I hope you will take note of our incident in considering your travel plans for the coming days.