Schartwand/Tennengebirge Werfenweng
Some facts and some personal view about our accident on Schartwand/Tennengebirge last Sunday:
We had level 3 in our avalanche bulletin for „Region Salzburg-Nordalpen“, which was mainly reasoned by a marked snow drift problem.
Around 15 – 20 cm new snow, which was transported by strong N/W winds „in steep ridgeline terrain, steep transitions distant from ridgelines, and in gullies“ so it was written. And further „the snow base is cold, soft and loosely-bonded, it covers the surface hoar. Drifts on cold, soft snow base easy to trigger as slab avalanche.“ According to this situation our plan was to operate really carefully and defensively.
On tour we noticed that most of the new snow was drifted in lower regions around the forest line. Around the summits and ridgelines was very little snow left and partly (especially on western exposed terrain) no snow at all. So our subjective impression was, that the situation for this tour is on the lower side of our avalanche bulletin.
The descent slope from Schartwand was S/E exposed and therefore according to avalanche bulletin predestinated for snowdrift deposit. It would have been possible to recognize this problem, but we went a different track uphill and didn't pass our descent line directly. From above down it was not easy to recognize, because the upper 50 m of the descent were completely blown out and hard frozen. Just the lower part was loaded with drifted snow then.
From my point of view our mistake was not to invest enough time to check our later skiing line from down below before we started ascending towards Schartwand. Obviously we were too inattentive because of our previous impressions of the day!
The slab width was around 150 m by only 10 – 20 cm fracture depth, which indicates some clearly defined bed surface below the winddrifted snow.
My personal suspicion is, that it could have been a „buried surface hoar“ (caused maybe by a so called „Nigg-Effect“) or a „warm on cold“ effect.
lp. Tom
P.S.:
Now also official report on http://www.lawine.salzburg.at/ereignisse/index2.php?id=124 is online!
Zadnja sprememba: 26.02.2023 ob 12:02