warming - cooling and stability

[damian 0]

The rapid warming of the snowpack (and rain) caused significantly reduced stability during and immediately following the warming. This has been well reported.

 

Will the subsequent drop in temperatures cause the previously warmed snowpack to end up more stable than it was before the warming? Will trouble layers have healed?

 

eg, using Yuzawa as a case study (forgive obvious lackings in my data and some generalisations):

 

- During first two weeks of January: the buried Jan 1 suncrust was reported as being evident in snow profiles.

- 14 Jan, temps at +11C in town.

- Jan 15, resort temps at +4C. Rain

- Remained mild until Jan 16

- Cooled off to -5C at the resort top

 

Will the quick warming and subsequent quick cooling have cured the sun crust weakness? Will the original snow pack be left in a more stable state? The reading I have done suggests that it may. Has this been the case in reality?

[montoya 0]

To make your scenario more interesting, major cracks have occurred well before Jan 1 at Kagura. How they affected the snowpack through this cycle is a concern. Stuff like this:

[damian 0]

ahh, I didn't know about the cracks. They are like glide slides? Perhaps that could add too the compressive(?) support lower down in the slope. I think what I am vaguely guessing at is that if the cracks appeared but no failure in sheer took place then perhaps the pack is historically stable in it entire depth. This is why the rapid warming lead to cautions of failure in the pack at the base, sliding off the grass like in spring. For cracks like that to form there must be an enormous amount of stress in the snow and it could be encouraging that it has survived the stress and re-hardened after the warm up. Lets hope it stays cold for the remainder of winter.

 

These pictures coming from the massive falls in Japan are quite striking. In parts, that looks like a glacier is under it! Take a 15m rope, some of those cracks look narrow and deep enough to annoy if you fell in one.

 

Spring will be interesting, when all this stuff starts to melt.

[montoya 0]

Yes, the look like glide cracks. I think they tend to occur when a thick snow pack develops quickly over wet or unfrozen ground, which describes this season neatly. Sometimes they fully release and go all the way to the ground. Sometimes it looks like it has gone away, when actually new snow and wind has just faintly concealed them. In your scenario I'd think about how much the sun affects it, with meltwater percolating through the snowpack and affecting the ground surface hold. Almost all that I have seen there have been on south-slopes.