Lower Thaynes Canyon Avy Observations

I made an attempt to ski the spruces in upper Thaynes Canyon this morning, but was turned back by the avalanche danger in the terrain traps in lower Thaynes. The drive up the unplowed road was pretty fun.

For those who are not familar with the drainage, down low in the canyon, the trail goes up a narrow gully with steep walls on at least one side. This is pretty low elevation (i.e. not much new snow from most storms) and wind sheltered, so normally they are fairly harmless. I've seen roller balls and point releashes on warmer days, but that's it.

I wish I had photos, because the terrain traps were far more impressive today. Everything that rolled over to 40 degrees or more had slid naturally in 4" to 6" soft slabs in the new snow. The point of the failure was not very visible as the new snow was sliding on the still soft, but more cohesive new snow. You could see these crowns every where, very impressive, everything had slid naturally. None of these slides managed to cross the very narrow gully - they were only running on the steeper areas. If this had been the only avy condition that I saw, I would have continued up and enjoyed blissful thigh deep powder.

The more interesting and intimidating avy condition on terrain just under 40 degrees that was beneath the the slopes that had slid near the gully bottom. These were still at least 35 degrees in angle. The snow that had slid accumulated in these slopes and had created some big, cohesive, really unstable soft slabs. I played around with some of these in a same location were the terrain trap was small any there was only about 8 vertical feet of these big slabs. Some of these slabs already had cracks in them. If was able to trigger failure in these slabs by skiing into them any watching a 8 foot wide slab break out 3 to 4 feet above me (the slab had no where to go, it moved about 6" down). These were ultra sensitive, kind of like Will when he wears that pink t-shirt. Depending on how much snow had slid down from above, they ranged in depth from 1 to 3 feet.

Since the terrain trap was going to get larger if I went up higher, with larger zones that would have slid to create larger slabs threatening the gully, I aborted. I can only imagine how dangerous similar slabs would have been in larger high evevation terrain. There would have been more snow, more wind, and major consequences. Ski cutting would not have been an option since that could break out from above, and it's pretty hard to carry enough momentum in waste deep powder. This is the sort of condition that occurs frequently in the apron of Wolverine Cirque. The upper chutes can be safe, having already slid, but there can be a large slab lurking below in the bowl. Upper Thaynes would have been really nice though.