Bergell, Poschiavo, Münstertal
Münstertal
Avalanche Problems
Persistent weak layers
2-
Field notes
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
The last few day’s new and drifted snow has stabilised well. However, this snow is lying on sometimes weakly bonded old snow. 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 deposited on the ground in a multiplicity of layers.EAWS glossary are located in particular on northern and sometimes on eastern slopes above around 2400 m. On the northern flank of the Alps, they are sometimes directly beneath the new and drifted snow layers and sometimes also in the middle of the snowpack. In inneralpine regions and in northern Grisons, they are sometimes also in the lower part of the snowpack.
The Snow deposited on the ground in a multiplicity of layers.EAWS glossary has been moistened by rain below 2400 m and is saturated up to around 2100 m. Isolated Avalanche of wet snow masses. Flowing more slowly than dry avalanches; usually for shorter runout distances, however with greater impact on obstacles due to higher snow density.EAWS glossary are possible with the sunshine and rising temperatures during the daytime. Isolated gliding avalanches are still possible.
Weather review for Tuesday
After a mostly clear night, conditions were mainly sunny in the mountains during the day.
Fresh snow
-
Temperature
At midday at 2000 m, between +8°C in the north and +5°C in the south.
Wind
Mostly light to moderate from southwesterly directions
Weather forecast to Wednesday
After a mostly clear night, conditions will be sunny and mild.
Fresh snow
-
Temperature
At midday at 2000 m, around +4°C
Wind
Light to moderate southwesterly
Outlook
After a sometimes cloudy night, there will be some sunny intervals on Thursday. Friday will be mainly sunny after a clear night. Temperatures will remain mild with a light to moderate southwesterly wind.
The danger of dry avalanches is decreasing, although only very slowly in areas with a 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 problem. The danger of wet avalanches follows a daily cycle and increases slightly over the course of the day. On steep grassy slopes, isolated glide-snow avalanches are possible.