Variable snowpack structure.
1) Higher elevation with northerly aspects there are reactive basal facets above a crust with a slab that varies between 50-60 cm.
2) At places characterized as "surface hoar gardens (steep meadows)", between 7-7600 feet with northerly aspects, buried at 26-30 cms there is a layer of large (2.5-3 mm) surface hoar crystal. This weak layer is reactive to stability testing. Yesterday it dramatically telegraphed us not to approach steep terrain, with a full large slopewise collapse after my third ski turn. Remote propagation continued to the adjacent slopes. The slope was only 28 degrees in steepness.
3) No evidence of buried basal facets or surface hoar at slopes with Easterly or south aspects below 7800 feet.
Bluebird day, relatively cold with calm to light winds. Radiation cooling at shady aspects was significant.
Good visibility. No avalanche releases.
Problem | Location | Distribution | Sensitivity | Size | Comments |
---|---|---|---|---|---|
Persistent Slab |
|
Layer Depth/Date: 26-30ncm Comments: Buried surface hoar, 2.5-3mm |
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Persistent Slab |
|
Layer Depth/Date: 50-60 cm Comments: Basal facets above melt-freeze crust |
Did not approach steep terrain. Shallow snowpack continues to be a significant hazard.