Bernese Oberland
Gadmertal
Avalanche Problems
Wind slab
2-
Field notes
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.
Snowpack & Weather
Snowpack
The snow depths at intermediate and high altitudes are generally below average for the time of year. There is particularly little snow on the southern flank of the Alps. Only in parts of Lower Valais is snow depth roughly in line with the long-term average. On southern slopes and generally below 2400 m, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is mostly crusted.
Along the Main Alpine Ridge and south of there, fresh and drifted snow will be deposited at high altitudes on a thin but heavily faceted Snow deposited on the ground in a multiplicity of layers.EAWS glossary on Tuesday. Avalanches are particularly likely to be triggered in these regions.
North of the Main Alpine Ridge, there are pronounced 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, particularly on northern and eastern slopes above approximately 2400 m, but hardly any avalanches have been triggered there in recent days by human activity. At high altitudes the strong southerly wind may transport some of the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary, resulting in snowdrift accumulations locally prone to triggering.
Weather review for Monday
Conditions were mostly sunny in the mountains, with high broken cloud gathering in the south-west and south from midday.
Fresh snow
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Temperature
At midday at 2000 m, between +4°C in the north and +1°C in the south
Wind
In the Alpine valleys in the north and generally at high altitudes, moderate, at times strong from southerly directions
Weather forecast to Tuesday
Towards Tuesday morning, precipitation will set in on the Main Alpine Ridge and south of there. The snowfall level will be at around 1200 m. In other regions, it will be mostly cloudy but dry.
Fresh snow
The following amounts will fall above 1600 m by Tuesday afternoon:
- Main Alpine Ridge from the Grand St Bernard Pass to the Bernina and south of there: 5 to 15 cm, with up to 20 cm in western Ticino and the Simplon region
- elsewhere dry
Temperature
At midday at 2000 m, between +4°C in the north and -2°C in the south
Wind
In the Alpine valleys in the north and generally at high altitudes, at times strong from southerly directions
Outlook to Thursday
During the night to Wednesday and on Wednesday morning it will be cloudy on the southern flanks of the Alps and in Grisons. Some snow may fall above 1600 m. In other regions, Wednesday will be very sunny. On Thursday conditions will be very cloudy but dry on the southern flank of the Alps, with sunny conditions elsewhere. Winds will be mostly light on Wednesday, and occasionally moderate on Thursday, from the southwest.
Avalanche risk may continue to increase slightly during the night to Wednesday on the southern flank of the Alps, but elsewhere will barely change.