Ticino Sopraceneri
Bleniotal
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
Between Wednesday and Saturday, snowfall accompanied by moderate to strong winds was widespread at high altitudes, with the largest amounts falling in the Bernese and Valais Alps and in the Bernina region. Around half a metre of snow fell above 2800 m in these regions. In Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary along the main Alpine ridge from the Monte Rosa region to the Bernina region, the fresh snow was deposited on a thin but already continuous Snow deposited on the ground in a multiplicity of layers.EAWS glossary. Faceted 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 present near the ground in these regions. Elsewhere, weak layers are to be expected mainly within the various layers of fresh snow and wind-drifted snow.
As the snowfall level rises to around 2600 m during the night to Sunday, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary will become moist or wet over widespread areas, including at high altitudes.
Outlook
Monday
On Monday, it will be partly cloudy in the north and mostly sunny elsewhere. The zero-degree level will rise to above 3000 m during the day. The wind will be mostly moderate from westerly directions.
The danger of dry avalanches will decrease. Particularly on steep north-facing slopes in Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary, avalanches can still be triggered by people. As a result of solar radiation, moist loose snow slides and avalanches are to be expected on steep slopes in high alpine regions.
Tuesday
On Tuesday, it will be mostly sunny and mild. The zero-degree level will rise to 4000 m. The wind will be light to moderate from westerly directions.
The danger of dry avalanches will decrease further. As temperatures rise, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary will become moist up to Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary altitudes. Small and medium-sized wet loose snow avalanches are possible. In addition to the danger of being buried, particular attention should be paid to the danger of being swept along and falling.