Northern San Juan
AvalancheColin Mitchell · Apr 8, 2021 · Northern San Juan
Weather
Cloudy and blustery. Periods of sun helped take the edge off, but overall a chilly day in the alpine.
Snowpack
We traveled West, South, and Northwest aspects near and above treeline. Supportable melt-freeze crusts were present on all but upper elevation northerly slopes (we topped out at 12,500'). As we moved above treeline, the sun and temperature effect waned, and we had a little cracking in the crust on the west-facing skin track near the end of the climb. We investigated and found about 15 cm of F-hard mixed forms under the upper crust, with a bullet-proof midpack under that. South-facing slopes at 12,500' were moist-to-wet melt forms and advanced rounding facets to the ground. The upper 50 cm or so had a centimeter or less of corn over a stout crust/slab of melt forms, with moist, 1f- hard rounding depth hoar under that. Water had penetrated to the ground, and drainage was well-established. Nearby northwest-facing slopes still held a cold, winter-like snowpack. The upper 20 cm or so was wind-packed facets. Below this was a strong mid-pack slab we could not penetrate with ski pole probing. It was clear that the recent warm up had little effect on these aspects in the alpine. We began to encounter a sun/temperature crust on these slopes as we dropped into near-treeline elevations. On our exit, we passed through the NW aspects in the below treeline band. As of 2 pm, the snowpack here was a few inches of corn over a supportable base.
Avalanche
No new activity observed today.