Red Mountain

Our goals today were to head to a location where we had heard reports of direct feedback from buried persistent weak layers, and to confirm our suspicions that recent avalanches failed on these layers. 

We had 1 audible collapse during the tour, and could see signs of old shooting cracks caused by other skiers. 

Our suspicions were correct, and the very large avalanche on Red Mountain broke in facets buried 2/10. 

Persistent Slab: We found old echelon cracks on northerly terrain between 9000' and 10000'. We had one audible collapse during the tour. Wind Slab: We had no direct signs of instability in recently drifted snow.

The structure in the Red Mountain area is poor. Around 70-100cm of recent snow is sitting on weak facets on northerly terrain around 9000'. Some notes:

• Generally, the 2/10 interface in this area does not have a melt-freeze crust capping the facets.
• Below 2/10 a variety of large (2-3mm) facets, decomposing crusts, and chained depth hoar exist
• Facets at the 2/10 interface are generally Fist+ or 4 Finger. The overlying slab is right side up, and Fist to 1 Finger at the base
• Around 9000', we had numerous ECTN differences within the storm snow, but did not initiate failure on the 2/10. We dug off the flanks of an old avalanche, and the weak layer may have already been impacted, collapsed, or influenced by the adjacent avalanche.

We also took a quick look at a very large avalanche on a northeast facing slope at 10800'. This avalanche broke in facets buried 2/10 and is a persistent slab. The crown was generally around 70cm, and it ran ~2500'. We found variability in the bed surface. In places, this avalanche appeared to have broken down to the 1/1 interface, to facets below 1/1, or all the way to the ground. 30cm of recently drifted snow had reloaded the start zone.