Colorado Avalanche Information Center

With Ann Mellick. Pit is an example of an emerging and evolving persistent weak layer. Some northeast aspects at all elevations are shallow. Where HS is around 120cm the lower half is 2mm facets mid pack and 3mm depth hoar. This location has a small, isolated slab on top. The slab is made up of multiple snow and wind events, now settled into the top 40cm. ECTP 21 @ 45 and CT 11 SC at 45 suggest that where this structure exists, stabilty is poor. So far this is still isolated as many of these shallow areas just dont have much of a slab on top.

Currently very stable due to multiple melt/freeze cycles. Chose pit location because pole probing sunk to the ground once through the surface crusts. Currently no avalanche hazard here but if the heat turns on soon and this structure goes isothermal, wet avalanches will be likely.

Pit dug adjacent to HS-N-R2,D2.5-O that occurred 4 days prior on Feb 24. Initial slide was a new snow wind slab that stepped down into weak faceted snow mid-pack and at the ground. SE-E aspects still have persistent weak layers that if given the right load will fail. This structure is becoming much more isolated however as the warm temps and stronger sun help with sintering. CT failures suggest once the strength of the slab is reduced failures are still possible.