Lower Valais
Génépi
Hard-to-read day. Deteriorating within moderate, with persistent weak layers and wet snow in play — you will see part of it, not all.
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
2
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
With the mild weather, moisture penetration into the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is well advanced. On south-facing slopes, the snowpack is moist 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. Initial moistening of 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 is now reaching around 2200 to 2400 m on north-facing slopes, and 2800 m on west- and east-facing slopes, and 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. The 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 in Grisons in particular are the least deeply buried, and it is here that wet slab avalanches are most likely also to be triggered by human activity. 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 continue to be a possible indication of a weak snowpack.
At higher altitudes, where the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is still dry, avalanches can in some places also still be triggered 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 occasionally in layers closer to the surface.
Weather review for Friday
Thursday night was mostly clear. During the day it was mostly sunny with high cloud and cumulus clouds developing in the afternoon.
Fresh snow
-
Temperature
At midday at 2000 m around +8 °C
Wind
Mostly light
Weather forecast to Saturday
Friday night into Saturday will be clear. During the day, it will be mostly sunny with some cumulus clouds in the afternoon.
Fresh snow
-
Temperature
At midday at 2000 m, around +6 °C
Wind
Mainly light
Outlook to Monday
The night into Sunday will be mostly cloudy. During the day, it will be mostly heavily cloudy in the north with showers and thunderstorms on the northern flank of the Alps. The snowfall level will drop from 2200 to 1800 m. In Valais, Ticino and the Engadine, it will be partly sunny. The westerly wind will pick up. Overnight to Monday, it will be mostly clear in Valais, Ticino and the Engadine, while elsewhere it will be mostly cloudy. During the day, there will be variable cloud cover with showers along the central and eastern northern flank of the Alps. Elsewhere, it will be quite sunny.
The danger of dry avalanches will not change significantly. The danger of wet avalanches will increase, particularly in Valais, Ticino and Grisons as the day progresses. Tours and hut approaches should be completed in good time. In the other regions, isolated wet avalanches are possible at any time.