This is my last weekly report for the season. I'll be away in the mountains of another place for the next 2 months.
Besides summarising, I won't repeat anything that is already available in the above sources of info. Please read them, especially the JAN avalanche bulletin. Seriously, if you are not reading the avalanche bulletin, then don't bother reading this either.
The last week:
A week ago today we had a snowpack which was mostly well settled. There were sun crusts about to get buried by a storm over the past weekend. Old buried layers had a chance of remaining weak, and they did. Deeper forgotten crusts activated as well. Firstly, on Sunday Natural storm slab avalanches were wide and large - numerous were big enough to bury a car- and they occurred on multiple aspects. Some more impressive crown walls were left on aspects with a sun crust. One avalanche on a SE aspect released naturally at 2000m on a weak layer formed before January 28th. You read that. The bed surface was under the thick obvious dust layer put down on Jan 28th. The deep overlying slab was well over 200cm and hard, containing multiple sun crusts. Thank you to a professional Member of the Japan Avalanche Network for going to look at it. On Monday we had warm sunny weather and it seemed in the space of a week people had forgotten the warm sunny unstable day a week ago, and terrain that requires good confidence in the snowpack was being hammered along Happo, despite large very recent natural avalanches everywhere around them. That is their choice I guess. During the week we had yet another warm spike with almost rain at valley bottom, and moistened snow to treeline. Then a cooling trend, stabilized recent snow under a slowly building layer of storm snow from Wed-Thur, which was being hit by sun and producing small natural loose avalanches. The sun is strong at this late stage in the [winter] season. We are on the same latitude as northern Morocco. Respect the sun from now.
Today is Thursday the 19th Feb. The snowpack is mostly well settled after the storm earlier in the week. There is a soft layer of storm snow available for wind transport. A short-lived winter pattern storm has just arrived and that will create a deeper possibly denser storm slab. And perhaps new windslab at ridge crests above treeline. New storm snow will sit on sun crusts on E, SE, S and SW and W aspects.
The next few days:
Storm tapering off on Friday, clear and warm on Saturday. Here we go again, when will luck run out? Sunday is the first solid looking rain event for the season, possibly reaching above treeline. Bad news, but later than normal this season, so we have been lucky. Hope for very heavy rain below treeline to load, weaken, and possibly release, deep slabs on old weak layers associated with sun crusts. They are down there. Then hope for a hard freeze which may bridge the deeper pack. The longer forecast looks like snow from Wednesday or so, possibly quite a bit. Snow on rain crusts, welcome to March in Hakuba.
Have fun. Think about the things you don't know. See you late April in Tateyama.