Quick report
Crown lines were observed in multiple aspects yesterday that likely cycled between 1/16 & 1/17. Debris we found on the floor of Tuckerman Ravine was a mix of large and small hard slab blocks with P hardness. Debris that came out of Left Gully felt a little softer, but still presented as hard slab.
Weather
- Cloud Cover
- obscured
- Wind Loading
- moderate
- Snow Avail For Transport
- small smounts
Observed obscured skies and freezing fog during most of our time in Tuckerman Ravine. Wind speed was moderate from the west, with gusts. Before leaving Tuckerman Ravine around 3:30 PM, the fog had lifted, and visibility improved.
Snowpack
The snow surface along the route we traveled varied between scoured melt-freeze crust from 1/10, soft new snow, and old hard snow. Areas of exposed 1/10 crust ranged from easy to break through and unsupportive to firm, slick, and supportable. Old hard snow was supportive and easy to travel on with minimal boot penetration. Areas of softer, new snow were found in isolated, wind-sheltered terrain above 4000 ft with boot penetration up to 75cm. A lot of softer new snow had filled in areas underneath the crown and in the track of the path.
2 ECT tests were performed on the crown line below Chute and resulted in propagation 65cm down within the F hard snow just above the 1/10 melt-freeze crust (ECTP23). 3 PST tests were performed and yielded no results on the same weak layer. The F hard layer of snow was about 5cm thick and had faceting grains on top of the melt-freeze crust. The slope above the crown line is still well-connected hard slab that is now unsupported. We observed the crown line in a thinner area and the depth was 65cm. The thickest part of the crown line could easily be 3-4 feet in depth, but it was hard to tell as a lot of new snow had filled back in.
Avalanche
Crown lines were observed in Hillman's Highway, Left Gully, and across the bottom of Chute. Our main objective was to look at the bed surface of the avalanche below Chute, as well as its sensitivity.