Central Grisons and Anterior Rhine
Albulatal
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
In Lower Valais, northern Valais and the Bernese Oberland, there is as much snow at high altitudes as usual for this time of year, but less in the other regions. There is particularly little snow on the southern flank of the Alps and at intermediate altitudes on the eastern part of the northern flank of the Alps. At 2000 m, there is 30 to 50 cm of snow on the northern flank of the Alps, 10 to 30 cm in southern Lower Valais, northern Upper Valais, the Gotthard region and northern and central Grisons, and less than 10 cm elsewhere.
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 eastern slopes above approximately 2400 m. Particularly in southern Valais and in some parts of the inneralpine regions of Grisons, human activity can cause these layers to fracture and trigger avalanches.
Below approximately 2400 m, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is moist under the mostly brittle Layer of hard-compacted snow resulting from a melt-freeze process; increases firmness.EAWS glossary; below approximately 2100 m, it is saturated. Isolated wet and gliding avalanches are possible with the sunshine and rising temperatures during the daytime.
Weather review for Friday
It was mostly sunny in the mountains.
Fresh snow
-
Temperature
At midday at 2000 m, between around +6 °C in the west and +4 °C in the east
Wind
Light to moderate from the west, decreasing during the course of the day
Weather forecast to Saturday
It will be sunny and mild with light winds in the mountains.
Fresh snow
-
Temperature
At midday at 2000 m, around +5 °C
Wind
There will be mostly light southwesterly winds.
Outlook
On Sunday and Monday it will be mostly sunny in the mountains. Clouds will set in from the southwest on Monday afternoon. The southwesterly wind will remain light on Sunday, but will freshen appreciably on Monday. It will remain mild.
The danger of dry avalanches will continue to slowly decrease. In regions with 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 in particular, persons can still trigger avalanches in places.
The danger of wet and gliding avalanches will increase slightly during the day with the sunshine and rising temperatures.