Gulf of Slides Snowfields

We traveled into the Gulf of Slides to assess snowpack structure after several professionals reported results indicating poor structure—specifically, strong, hard slabs over weak faceted snow with propagation potential.

In Main Gully, tests on Sunday (2/1) produced an ECTP8 on faceted precipitation particles.

On Thursday (2/5) in  Gully 5  E aspect at 4200 ft, results included an ECTPV down 40 cm, failing on decomposing precipitation particles transitioning -> facets. The snowpack consisted of a 1F hard slab over fist-hard faceted snow, a strong-over-weak structure that was found continuously throughout the gully.

In the Snowfields, a similar snowpack structure was observed by probing around 4200 ft, at 4300 ft a PST 43/100 (End) failed down 50 cm on a faceted weak layer. Higher in the Snowfields at 4520 ft, an ECTP23 failed down 40 cm on faceted grains. Probing while traveling through this terrain consistently revealed a punchy hard-over-weak structure, and the hard slab appears well connected across the landscape.

The slab above this weak layer is very supportive, with minimal penetration from both boots and skis.

With continued cold temperatures, this faceted layer may continue to weaken. Tracking PST cut lengths over time will be useful for monitoring trends in propagation potential. Key questions moving forward include how much additional load is required to stress this structure, and whether triggering could occur from multiple people, new wind or storm loading, or a surface avalanche stepping down to this layer.

Questions I’m thinking about with this layer include how much additional load it takes to stress this structure, and whether that load could come from a group of people, new snow, or from a surface avalanche stepping down.

Pit #1 - E aspect, 4300ft, 24 deg slope

• total snowpack depth 280cm - Pit depth 70cm
• weak layer faceted grains 50cm down sandwiched between two pencil+ hard layers - ECTN14 - PST 43/100 End

Pit #2 - ESE aspect, 4520ft, 36 deg slope

• Pit Depth 70cm
• 2 weak layers approximately 40 and 50cm down. 1/10 MF Ice crust 70cm down 
• This path avalanched on 1/26
• ECTP23 down 40 cm faceted grains, PSTX - no result