Vaud Alps
Jaun
Stable day. Low, with wet snow and gliding snow named together — one of them visible at the surface, the other buried.
Day Risk Profile
Avalanche Problems
Wet snow + Gliding snow
1
Field notes
Wet snow
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.
Gliding snow
Almost impossible to predict precisely, even when the warning signs are visible. A crack visible on the snowpack surface formed by snow-gliding on steep, and particularly grass-covered slopes. Areas below slopes with visible glide cracks should be avoided whenever possible due to threat of gliding sluffs or avalanches.EAWS glossary — gaps that open in the Snow deposited on the ground in a multiplicity of layers.EAWS glossary down to the ground — are often precursors to release, but they don't tell you when. A glide avalanche can release minutes after the cracks appear, or weeks later, or not at all. Some release without any visible warning. Avoid lingering anywhere near glide cracks: above them, alongside them, or below in the runout.
Snowpack & Weather
Snowpack
Moisture penetration into the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is well advanced. The most precarious areas are slopes where 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 layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary are becoming wet for the first time. At present, this mainly affects north-facing slopes between approximately 2200 and 2500 m, and east- and west-facing slopes between approximately 2500 and 2800 m. On south-facing slopes, the snowpack is thoroughly moist as far as into the Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary. In Grisons, the weak layers in the old snowpack are the least deeply buried, which means that 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 can also be triggered by human activity in some places.
Higher up, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is still dry. There are still 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 layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary, but no more dry avalanches have been reported in recent days.
Weather review for Wednesday
In the south, it was very cloudy and a few snowflakes fell locally above 2000 m. There was rain in the Sotto Ceneri. Otherwise, the night was mostly clear and the day sunny.
Fresh snow
-
Temperature
At midday at 2000 m, around +2 °C
Wind
- Often moderate from north to west during the night, mostly light during the day
- Bise wind along the Prealps
Weather forecast to Thursday
In the far south, the night into Thursday will be cloudy with some rain; it will become increasingly sunny during the day. In the north, it will be mostly sunny after a mostly clear night.
Fresh snow
-
Temperature
At midday at 2000 m, around +5 °C
Wind
Light to moderate northeasterly
Outlook to Saturday
The nights will be clear, and with the dry air, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary will freeze at high altitudes to become capable of bearing loads. The days will be sunny and mild; the zero-degree level will be around 3200 m. The winds will be mostly light.
The danger of dry avalanches will not change significantly. This means that in the early morning, touring conditions will be favourable over a wide area. Each day, the danger of wet avalanches will increase appreciably as the day progresses. Ski tours and hut ascents should be completed in good time.