Ticino Sopraceneri
Untere Maggiatäler
Hard-to-read day. Moderate all day, with wind slab, persistent weak layers and wet snow across the two halves — the level holds; what changes is what sits under it.
Day Risk Profile
Problem type changes as the day progresses
Avalanche Problems
Wind slab + Persistent weak layers
2=
Field notes
Wind slab
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.
Persistent weak layers
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
In the Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary, the larger amounts of new snow from the last four days and the drifted snow are still prone to triggering in some cases. In addition, 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 embedded in the near-surface layers of the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary, especially on steep north-facing slopes. Avalanche observations from recent days confirm that these weak layers are prone to triggering.
A Layer of hard-compacted snow resulting from a melt-freeze process or wind.EAWS glossary has formed beneath the new snow. Below this, 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 sweep away 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 saturated for the first time.
Weather review for Thursday
During the night into Thursday, precipitation continued to fall, mainly in Ticino and Grisons. During the day, there were sunny spells between residual cloud and cumulus clouds. Valais, Ticino and southern Grisons saw the most sun.
Fresh snow
From Wednesday afternoon to Thursday afternoon with a snowfall level of 1700 to 2000 m:
- from Avers via Val Bregaglia to the Bernina region: 20 to 40 cm
- from the Aletsch region via Goms to the Rheinwald region and south of there: 10 to 20 cm
- elsewhere a widespread 5 to 10 cm
This means that over the four days from Sunday afternoon to Thursday afternoon, altitudes above approximately 2800 m saw the following snowfall:
- Lower Valais on the border with France, Aletsch region to Susten region, Main Alpine Ridge from Monte Rosa to the Bernina region and south of there: mostly 30 to 60 cm
- rest of Valais: 15 to 30 cm
- Less elsewhere
Temperature
At midday at 2000 m, between +2 °C in the northeast and +7 °C from the Visp valleys to western Ticino
Wind
Southwesterly
- During the night into Thursday, often moderate at high altitudes
- Easing during the day
Weather forecast to Friday
Skies will mostly be clear overnight to Friday. During the day, it will be quite sunny with cumulus clouds and isolated showers and thunderstorms as the day progresses.
Fresh snow
-
Temperature
At midday at 2000 m, around +6 °C
Wind
Mostly light from southerly directions, moderate at times in the Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary
Outlook to Sunday
The night into Saturday will be mostly clear. During the day, it will be quite sunny on the southern flank of the Alps, otherwise mostly sunny with cumulus clouds and isolated showers as the day progresses. During the night into Sunday, cloud cover will increase from the southwest. On the southern flank of the Alps, it will be very cloudy with showers as early as the late morning. On the central and eastern parts of the northern flank of the Alps and in northern Grisons, there will be a foehn wind and it will still be partly sunny at first. Cloud cover will increase here as well later on. The zero-degree level will be around 3000 m on both days.
The danger of dry avalanches will decrease. Caution is still required in particular on steep north- and east-facing slopes in regions with a lot of fresh snow at high altitudes. On Saturday, the danger of wet avalanches will change in the course of the day; on Sunday, it will increase even in the early morning, especially on the southern flank of the Alps. Otherwise it will increase as the day progresses. Isolated wet avalanches which sweep away 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.