Northern San Juan
SnowpackRebecca Hodgetts Chris Bilbrey · Feb 28, 2024 · Northern San Juan
Weather
Beautiful sunny day with generally light wind. Temperatures moderated quickly following last night's frigid temperatures (Eagle weather station warmed from -4 F to 22 F).
Snowpack
The last storm delivered a right-side-up storm slab that showed generally good bonding to old snow surfaces - weak facets, hard wind layer, and firm crusts. We saw evidence of drifting at all elevations from strong winds that accompanied snowfall. South to west-facing alpine slopes looked wind-battered, scoured, and only isolated areas held fresh snow. Northerly and easterly-facing slopes were a mix of wind-pressed wavy surfaces adjacent to smooth, phat looking places. No cracking or collapsing along our travels, even when jumping on small test slopes or drifted pockets near and below treeline. We dug two snowpits, one on a north-facing below treeline slope at 10,800 feet, and the second on an east-facing slope at treeline around 12,000 feet. In our below treeline location, we tried to pick a wind-sheltered area, but the wind had affected most areas of the slope. Height of snow was 140 cm with around 10 cm of new snow. Snowpack tests at this location did not produce any notable failures - ECTX. Higher up, we dug on an east-facing slope adjacent to a very recent rider-triggered slide. At this location, we found around 35 cm of new snow sitting on top of a 1F to P hard wind-layer that formed in the week preceding the last storm. Below that was a 1F- layer of faceted grains. Snowpack tests produced sudden planar failures with 4 taps in Compression Tests, and Extended Column Tests produced a propagating result with 11 taps. Both failed at the same faceted interface around 40 to 45 cm deep. Descending an east-northeast-facing slope, ski pressure did not contribute to downhill snow movement, even where we could feel the crust below. There was a stark difference between full-sun and partially-shaded areas of the slope. We suspect a fresh crust will develop on all sunny slopes once they are shrouded in shade later today.