Southern San Juan
SnowpackChris Bilbrey · Jan 9, 2020 · Southern San Juan
Weather
Cloudy skies to start the day with obscured peaks around 11 am. Light snow showers gave way S2 around Noon then steady S5 for a couple hours. By 3:30 pm, we measured 7" of new snow on a north aspect at 10,800 feet. Winds were steady near and above treeline providing a good period of wind-loading along exposed ridges.
Snowpack
We found generally safe avalanche conditions on all aspects near and below treeline. The old snow surface ranges from a breakable melt-freeze crust to weak cohesionless facets to firm wind-effect. New snow was not slabby and produced only minor sluffing on steeper test slopes. We only observed isolated surface cracking in deeper drifts. Recently formed hard slabs were stubborn to ski pressure and while jumping on test slopes with sharp changes in slope steepness. However, long-column test still produced propagating test results. This demonstrates the character of a hard slab and being able to support a lot of weight before failing erratically. The old snow surface in the alpine was a mix bag of smooth wind-board to wavy sastrugi. These different surface textures may have an impact on storm snow bonding. Places where the old snow surface is smooth might be more reactive to rider triggering than slopes with significant surface roughness - as depth of the new slab increase.