On south-facing slopes, the snowpackSnow deposited on the ground in a multiplicity of layers.EAWS glossary is water-saturated 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. Moistening of the snowpack is progressing on northwest- to northeast-facing slopes between 2000 and 2500 m. It is especially on these aspectsDirection 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 slab avalanchesThe 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 as near-ground weak layersSnowpack 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 become moist for the first time. Weak layers in the old snowpackSnow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary are most pronounced in the inneralpine regions of Valais and Grisons and it is especially here that wet slab avalanches triggered by human activity are also to be expected.

In addition, isolated avalanches may still be triggered at higher altitudes in the dry old snowpackSnow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary or in the fresh and drifted snow from the beginning of the week.

There were clear spells overnight to Wednesday. If was often cloudy in the Prealps and in the south during the day but very sunny elsewhere.

Fresh snow

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Temperature

At midday at 2000 m, between +8 °C in the west and +5 °C in the east

Wind

Mostly light from southerly directions

There will be clear spells overnight to Thursday. Low cloud means that there will only be sunny intervals during the day in the north and east, while it will be mostly sunny elsewhere in the mountains.

Fresh snow

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Temperature

At midday at 2000 m, between +4 °C in the north and +6 °C in the south

Wind

Light from northerly directions

On Friday, after a mostly clear night, it will be quite sunny during the day despite passing high clouds. On Saturday, after a clear night, it will be mostly sunny during the day on Saturday. The zero-degree level will be around 3000 m on both days and winds will be light.

The danger of dry avalanches will continue to decrease. Conditions will be very favourable in the morning. Each day, the danger of wet avalanches will increase as the day progresses. Off-piste skiing and hut ascents should be completed in good time.