Storm Snow Instability

We traveled into the Throne on a snow-covered road, but unfortunately, by the time we came out at the end of the day, it was a couple of miles of off-and-on mud. I can't really see how the road will last beyond the end of the snowstorm for snowmobiling. By the time we turned off the road for the final ascent to the sled boundary, there was a foot of new snow, and by the top of the Throne, over two feet of new snow equal to 2.5" SWE. 

There was a thick, supportable crust below the new snow, and our primary concern was instability within the new snow and on wind-loaded slopes. A skier triggered a small avalanche on a steep north-facing pitch, but it did not run far. We saw limited cracking on a layer within the new snow generally 4" to 1 foot deep, and got an ECTP11 on this layer in one of our pits on the east-facing pitch near the standard ski track. Our other pits, one lower on the east face and to the north of the saddle at the top of the Throne, resulted in ECTNs between 5 and 15 on this layer within the new snow. While there was some limited wind transport of the new snow, we did not find any slopes that I would define as wind-loaded to test instability. My educated assumption is that you could trigger a large avalanche on a wind-loaded slope right now. 

While we traveled in and skied avalanche terrain, we stuck to the lower-angle end of the spectrum and selected simple slopes with fewer terrain traps. 

The new snow will provide fresh ammunition for wet, loose avalanches as the temperatures warm this week.