Bernese Oberland
Gadmertal
Day Risk Profile
Avalanche Problems
Wind slab + Persistent weak layers
2+
Field notes
Wind slab
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.
Persistent weak layers
Persistent Snowpack layer in which the crystals are poorly bonded and the layer has the potential to fail. Typical crystals in dry weak layers causing avalanches are : precipitation particles; surface hoar; faceted crystals; hollow crystals; graupel. Generally >1mm in size, loose grains with few bonds Wet weak layers can be formed by all snow crystal/grain types.EAWS glossary are very challenging to recognise. 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 and shooting cracks are typical when present, but you can have a serious weak layer with no warning signs at the surface. Knowledge of how the Snow deposited on the ground in a multiplicity of layers.EAWS glossary has evolved is essential. SLF's travel advice is direct: travel conservatively, avoid terrain where the consequences of being caught are large, and treat the history of weather and snow as more important than what you can see today. Read the full bulletin.
Snowpack & Weather
Snowpack
There are distinct Snowpack layer in which the crystals are poorly bonded and the layer has the potential to fail. Typical crystals in dry weak layers causing avalanches are : precipitation particles; surface hoar; faceted crystals; hollow crystals; graupel. Generally >1mm in size, loose grains with few bonds Wet weak layers can be formed by all snow crystal/grain types.EAWS glossary in the middle and lower part of the Snow deposited on the ground in a multiplicity of layers.EAWS glossary, particularly on wind-protected shady slopes. These are particularly common south of a line from the Rhône to the Rhine and on the southern flank of the Alps. In these weak layers, medium-sized and sometimes even large avalanches can still be triggered by human activity. The snowpack on northern and eastern slopes in Valais, as well as in northern Grisons, is particularly prone to triggering. Remote triggering is still possible in these areas in particular. The most recent avalanches triggered in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary were reported on the northern flank of the Alps at the weekend.
Weather review for Tuesday
It was cloudy on the southern flank of the Alps. Some snow fell at times above 1000 m. It was sunny in the other regions.
Fresh snow
A few centimetres in the southern Simplon region and in Valle Maggia
Temperature
At midday at 2000 m, between +1 °C in the north and -4 °C in the south
Wind
From the south:
- Moderate and occasionally strong on the northern Alpine ridge
- Elsewhere light to moderate
Weather forecast to Wednesday
Conditions will be sunny in the mountains.
Fresh snow
-
Temperature
At midday at 2000 m, between 0 °C in the north and -4 °C in the south
Wind
Mostly light southwesterly to westerly winds
Outlook to Friday
On Thursday it will be sunny in the east. Clouds will gather in the west and south. On Friday it will be cloudy in the west and south, with precipitation on the Main Alpine Ridge and to the south of it in the afternoon. The snowfall level will be at low altitude. There will be sunny intervals in the east.
The avalanche danger will continue to decrease slowly. Snowpack layer in which the crystals are poorly bonded and the layer has the potential to fail. Typical crystals in dry weak layers causing avalanches are : precipitation particles; surface hoar; faceted crystals; hollow crystals; graupel. Generally >1mm in size, loose grains with few bonds Wet weak layers can be formed by all snow crystal/grain types.EAWS glossary in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary will remain prone to triggering, especially in the inneralpine regions.