Bergell, Poschiavo, Münstertal
Münstertal
Hard-to-read day. Deteriorating: moderate this morning, considerable by afternoon, with persistent weak layers and wet snow in play — only half of it will be visible.
Day Risk Profile
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.
Wet snow
3
Field notes
Rolling snowballs, deep penetration when you step or ski, and small natural slides are clear signals that the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is losing strength. After a clear, cold night the surface often freezes into a strong supporting Layer of hard-compacted snow resulting from a melt-freeze process or wind.EAWS glossary, and conditions are favourable in the early morning. After a warm, overcast night, the problem may be present from the start of the day. Plan early returns and watch the runout zones below you.
Snowpack & Weather
Snowpack
On south-facing slopes, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is water-saturated up to around 3000 m, on east- and west-facing slopes up to 2500 to 2700 m, and on north-facing slopes up to around 2000 m. Moistening of the snowpack is progressing on northwest- to northeast-facing slopes between 2000 and 2500 m. It is especially on these Direction in which a slope faces as indicated by compass direction of the fall line; i.e. a north slope faces in a northerly direction.EAWS glossary and at these altitudes that large and occasionally even very large wet The abrupt release of a slab of snow on a mountain slope. After crack initiation and crack propagation in a weak layer the released slab comprises 3 elements: The weak layer, the gliding horizon and the slab. If the slope angle is steep enough, the slab will glide down. If the slope is not steep enough, the slab will settle down on the failed weak layer. Possibly a whumpf sound will follow due to air pressed out of the weak layer. The fracture line will be sharp edged.EAWS glossary may be triggered naturally as near-ground 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 become moist for the first time. Weak layers in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary are most pronounced in the inneralpine regions of Valais and Grisons and it is especially here that wet slab avalanches triggered by human activity are also to be expected.
In addition, isolated avalanches may still be triggered at higher altitudes in the dry Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary or in the fresh and drifted snow from the beginning of the week.
Weather review for Wednesday
There were clear spells overnight to Wednesday. If was often cloudy in the Prealps and in the south during the day but very sunny elsewhere.
Fresh snow
-
Temperature
At midday at 2000 m, between +8 °C in the west and +5 °C in the east
Wind
Mostly light from southerly directions
Weather forecast to Thursday
There will be clear spells overnight to Thursday. Low cloud means that there will only be sunny intervals during the day in the north and east, while it will be mostly sunny elsewhere in the mountains.
Fresh snow
-
Temperature
At midday at 2000 m, between +4 °C in the north and +6 °C in the south
Wind
Light from northerly directions
Outlook to Saturday
On Friday, after a mostly clear night, it will be quite sunny during the day despite passing high clouds. On Saturday, after a clear night, it will be mostly sunny during the day on Saturday. The zero-degree level will be around 3000 m on both days and winds will be light.
The danger of dry avalanches will continue to decrease. Conditions will be very favourable in the morning. Each day, the danger of wet avalanches will increase as the day progresses. Off-piste skiing and hut ascents should be completed in good time.