a question about PWL

[Rossymcg]

Euro sides, we've had a hotter than normal summer and it's continued in to autumn.
My uneducated thinking, could the ground temps being warmer for later in to the autumn be the cause of a persistent weak layer once the snow covers and the temps do drop?

Sent from my SM-G780G using TGR Forums mobile app

[raisingarizona13]

That's a lot of stinking over-thinking. JK.

I think I see where you're going with that but personally I wouldn't think it makes that much of a difference. I could be wrong though.

[Rossymcg]

probably just over thinking it.

Sent from my SM-G780G using TGR Forums mobile app

[doebedoe]

Ground temps under snow don't vary much staying close to 0C. Faceting occurs because it's colder above the snow than below. So cold dry places like Colorado get lots of faceting. Places that see more melt/freeze or warmer temps get less.

[Rossymcg]

Ground temps under snow don't vary much staying close to 0C. Faceting occurs because it's colder above the snow than below. So cold dry places like Colorado get lots of faceting. Places that see more melt/freeze or warmer temps get less.

OK. so if the ground temp stayed circa 0* and a beast from the east rolled in on a thin pack it could create a nasty PWL

Sent from my SM-G780G using TGR Forums mobile app

[MagnificentUnicorn]

Basal facets aren’t always a problem, depends on the surface of the ground. Is it a smooth planar surface or is it rocky and irregular? Where I ski most of the time, far east sub range of the Cascades in WA, there’s always basal facets but it’s really not a problem because it’s on top of very irregular fractured basalt. It’s usually faceted snow higher up in the snow pack on top of a crust that I worry about. Usually wind/storm slab over surface hoar that forms during cold clear weather.


Sent from my iPhone using TGR Forums

[cultvo]

Here in Switzerland, the ground has indeed entered winter warmer than normal during some recent years, it's been a topic of conversation amongst the varied winter professionals. What I have seen is areas that usually have glide cracks have them worse, and much earlier in the season. In some cases a couple areas like these, which tend to slide to ground in the spring, have slid to ground in December. The areas that exhibit this problem tend to be on grassy slopes or slopes with a lot of short but thick vegetation. It has not been a widespread problem within the snowpack. The recent seasons we have had widespread PWL problems, it has been significant amounts of early season snow followed by an extended period of high and dry that has caused the problem.

[subtle plague]

Here in Switzerland, the ground has indeed entered winter warmer than normal during some recent years, it's been a topic of conversation amongst the varied winter professionals. What I have seen is areas that usually have glide cracks have them worse, and much earlier in the season. In some cases a couple areas like these, which tend to slide to ground in the spring, have slid to ground in December. The areas that exhibit this problem tend to be on grassy slopes or slopes with a lot of short but thick vegetation. It has not been a widespread problem within the snowpack. The recent seasons we have had widespread PWL problems, it has been significant amounts of early season snow followed by an extended period of high and dry that has caused the problem.

Just to add: snowcovers thst create an early season pwl are NOT very signifikant.

If it's more than 1m of compacted snow Cover ( like after 3 or 4 days after the dump) it's enough to prevent pwl build up.
But you need massive first snow falls to create that. Like 150cm to 200cm of snowfall in a short period. It happened a few years ago where everything was a Cluster fuck except southern Switzerland where they had a massive base from two early season dumps.