Upper Valais
Leukerbad - Lötschental
Manageable day. Moderate all day, with wind slab and wet snow across the two halves — same number morning and afternoon, different problem behind it.
Day Risk Profile
Problem type changes as the day progresses
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.
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
New snow and drifted snow and in some cases near-surface layers in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary are prone to triggering at high altitudes, especially on steep north-facing slopes. The layers of new and drifted snow are thickest on the Main Alpine Ridge from the Saas Valley to the Bernina region and south of there. In other regions, fresh snowdrift accumulations are mostly small to medium-sized.
Below the new snow, the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary is moist up to high altitudes. As a consequence of solar radiation, loose snow avalanches are to be expected on very steep slopes, especially in the regions with a lot of fresh snow. Avalanche of wet snow masses. Flowing more slowly than dry avalanches; usually for shorter runout distances, however with greater impact on obstacles due to higher snow density.EAWS glossary, which can entrain the entire Snow deposited on the ground in a multiplicity of layers.EAWS glossary, are possible in isolated cases, especially as the day progresses. This applies particularly to north-facing slopes between 2200 and 2600 m, where the snowpack is becoming wet for the first time.
Weather review for Wednesday
After a mostly cloudy night, there was hardly any sunshine during the day. Snow fell above approximately 2000 to 2400 m, especially on the Main Alpine Ridge and south of there.
Fresh snow
From Tuesday afternoon to Wednesday afternoon above approximately 2600 m:
- Main Alpine Ridge from the Saas Valley to the Bernina region and south of there, from the Trient region to Great St. Bernard region and from the Aletsch to the Susten region: 20 to 40 cm
- Less elsewhere
Over the three days from Sunday to Wednesday afternoon, altitudes above approximately 2800 m thus saw the following snowfall:
- On the Main Alpine Ridge from the Monte Rosa to the Bernina region and south of there: mostly 30 to 50 cm
- In Lower Valais on the border with France, on the rest of the Main Alpine Ridge in Valais, on the Northern Alpine Ridge from Les Diablerets to the Susten region: mostly 15 to 30 cm
- Less elsewhere
Temperature
At midday at 2000 m, between +2 °C in the west and south and +4 °C in the east
Wind
Mostly moderate from southerly directions
Weather forecast to Thursday
Skies will only partially be clear overnight to Thursday. Some precipitation will continue to fall, especially in the south and east. During the day, it will be quite sunny with cumulus clouds and isolated showers and thunderstorms.
Fresh snow
During the night into Thursday, the following amounts of new snow will fall, with a snowfall level of approximately 2200 m:
- On the Main Alpine Ridge from the Rheinwald to the Bernina region: 10 to 20 cm
- Elsewhere a few centimetres. It will remain dry in the west.
Temperature
At midday at 2000 m, around +4 °C
Wind
From the south to southwest, mostly light, at times moderate in the Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary
Outlook to Saturday
The night into Friday will be mostly clear, and the night into Saturday partly clear. During the day on Friday and Saturday, it will be partly sunny on the southern flank of the Alps, and mostly sunny elsewhere. Winds will be mostly light southerlies on both days. The zero-degree level will be around 2800 m.
The danger of dry avalanches will decrease, but only slowly on steep west-, north- and east-facing slopes in regions with a lot of fresh snow at high altitudes. The danger of wet avalanches is once again becoming more closely linked to the time of day. Isolated wet avalanches which entrain the entire Snow deposited on the ground in a multiplicity of layers.EAWS glossary are possible, especially on north-facing slopes between 2200 and 2600 m.