Bernese Oberland
Engstligen
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.
Snowpack & Weather
Snowpack
North of a line from the Rhone to the Rhine and in the extreme west of Lower Valais, 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 mostly thickly covered and can only rarely be triggered by human activity.
South of a line from the Rhône to the Rhine, the 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 that have persisted since the beginning of January are still present. However, the number of avalanche-prone locations has decreased significantly. Reports of avalanches and alarm signs indicate that the situation in Grisons remains the most precarious.
With moistening of the Snow deposited on the ground in a multiplicity of layers.EAWS glossary on sunny slopes, some moist 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 have been triggered by human activity in the weakly bonded old snow in recent days. This is particularly the case around the treeline in Grisons.
Weather review for Sunday
The night to Sunday was overcast at times with isolated showers in the north. During the day, conditions were mosty cloudy with showers in the south. Otherwise conditions were mostly sunny at high altitudes, though Grisons was often cloudy.
Fresh snow
Above 1800 m, a few centimetres locally
Temperature
At midday at 2000 m, around 0 °C
Wind
Light to moderate from southerly directions
Weather forecast to Monday
The south will be very cloudy, with some precipitation. The snowfall level will be between 1600 and 1800 m. In the north, the night will be mostly clear, with cloudy intervals in Grisons. The daytime will be mostly sunny.
Fresh snow
On the central part of the southern flank of the Alps above 2200 m, 5 to 10 cm
Temperature
At midday at 2000 m, around +1 °C in the north and -2 °C in the south
Wind
Mostly light from southerly directions
Outlook to Wednesday
On Tuesday and Wednesday, mostly clear nights will be followed by sunny daytime conditions and light winds. The zero-degree level will be around 2000 m.
The danger of dry avalanches will continue to decrease, but only slowly in Grisons due to the weak Snow deposited on the ground in a multiplicity of layers.EAWS glossary structure. Each day, the danger of wet avalanches will increase somewhat as the day progresses.