Lower Valais
Montana
Avalanche Problems
Wind slab
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Field notes
Look for fresh snow deposits on Slope facing downwind/ wind sheltered aspect. Snow deposits can attain several times average snow depth.EAWS glossary, in Usually a steep, elongated, eroded trench; typically prone to snowdrift accumulation.EAWS glossary and Rounded or elongated concavity; typically tending to accumulate snowdrift.EAWS glossary, and behind ridgelines and abrupt changes in terrain — these are where the wind has loaded the snow into slabs that are easy to trigger. Recent avalanches, shooting cracks under your weight, and Distinctive noise (resembling a “whumpf” sound) occurring when a weak layer beneath a slab collapses. The air of the weak layer is forced outside the snowpack, with the resulting whumpf sound being heard. The sound usually indicates an unstable situation and can be accompanied by surface cracking. A whumpf is a clear avalanche alert.EAWS glossary sounds are clear confirmations of the problem. The safest move is to avoid wind-loaded terrain entirely. NB wind signs alone don't always mean an avalanche problem exists, and the age of drifted snow is hard to judge.
Snowpack & Weather
Snowpack
New snow and drift snow from Sunday is mostly well bonded with the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary. In the regions exposed to heavier precipitation, avalanches may be triggered in some places within the fresh and drift snow.
Isolated avalanches may also be triggered near to the ground in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary. This is particularly the case on northern slopes above approximately 2800 m and in the Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary in general.
Weather review for Saturday
Despite high cloud cover, it was still quite sunny in the late morning in the east, elsewhere mostly cloudy. In Ticino, there were small amounts of precipitation locally, falling as snow above approximately 2600 m.
Fresh snow
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Temperature
In the middle of the day at 2000 m at +8 °C in the north and +6 °C in the south
Wind
Moderate to strong from south to south-west
Weather forecast to Sunday
There will be widespread precipitation, which will intensify during the day. The amount of precipitation is still quite uncertain. The snowfall level will drop from 2600 m to around 1800 m in the north and around 2400 m in the south.
Fresh snow
From Saturday evening to Sunday afternoon, in the north above approximately 2600 m and in the south above approximately 3000 m:
- Main Alpine Ridge from the Lukmanier Pass to the Bernina Pass: 20 to 40 cm
- Otherwise a widespread 10 to 20 cm, in the extreme west of Lower Valais up to 30 cm
Temperature
At midday at 2000 m, around 0 °C in the north and +4 °C in the south
Wind
Moderate with a strong southwesterly wind at high altitudes, which will turn into a westerly wind as the day progresses
Outlook
Another 10 to 20 cm of snow will fall overnight to Monday. The snowfall level will drop to around 1400 m. During the day it will be partly cloudy towards the east, but sunny elsewhere. There will be a strong northerly wind in the south. The danger of dry avalanches will not change significantly. As a result of sunshine and warming temperatures during the day, glide snow avalanches and numerous loose snow avalanches are to be expected, particularly in the regions with a lot of new snow.
On Tuesday it will be sunny and very mild. The zero-degree level will rise to 3600 m. The avalanche danger will decrease.