Day Risk Profile

Moderate

Considerable

Later

Avalanche Problems

Dry avalanches, whole day

Persistent weak layers 2=

N, NE, NW

above 2600m

In some places dry avalanches can be released in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary. In isolated cases avalanches are large. These Locations delineated by aspect or altitude where avalanches can trigger and people or objects are at risk.EAWS glossary are barely recognisable, even to the trained eye. Caution is to be exercised in areas where the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is rather shallow in little used backcountry terrain.

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.

Source: SLF Avalanche Bulletin Interpretation Guide

Wet-snow avalanches, as the day progresses

Wet snow 3

N, E, S, W

below 2400m

As the day progresses as a consequence of warming during the day and solar radiation there will be an increase in the danger of wet avalanches. Caution is to be exercised in particular on steep north facing slopes below approximately 2400 m, as well as on steep east, south and west facing slopes between approximately 2500 and 3000 m. Wet avalanches can be released in the weakly bonded old snow by people. Isolated 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 penetration of the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary can indicate the danger. Avalanches can reach large size. Backcountry tours and ascents to alpine cabins should be started early and concluded timely.

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.

Source: SLF Avalanche Bulletin Interpretation Guide

Snowpack & Weather

Snowpack

With the mild weather, moistening of the Snow deposited on the ground in a multiplicity of layers.EAWS glossary is at an advanced stage. 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 2700 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 in layers closer to the surface.

Weather review for Thursday

Overnight to Thursday, skies were only occasionally clear. During the day, conditions were mostly sunny in the high mountains and towards the south and increasingly sunny elsewhere.

Fresh snow

Temperature

At midday at 2000 m, between +8 °C in the west and south and +3 °C in the east

Wind

Overnight to Thursday, moderate westerly at times at high altitudes
Mostly light during the day

Weather forecast to Friday

Skies will be clear overnight to Friday, and during the day conditions will be mostly sunny with high cloud developing as the day progresses and some cumulus clouds in the afternoon.

Fresh snow

Temperature

At midday at 2000 m, around +6 °C

Wind

Light from northerly directions

Outlook to Sunday

The night to Saturday will mostly be clear. During the day, conditions will be mostly sunny with cumulus clouds in the afternoon and scattered showers. The zero-degree level will remain at around 3000 m. Skies will only occasionally be clear overnight to Sunday. During the day, there will be only occasional sunshine, with increasing showers in the north. The snowfall level will be around 2300 m.

The danger of dry avalanches will not change significantly. The avalanche situation will generally be favourable in the morning, but 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.

Source

SLF

Issued

16 Apr 15:00 UTC

Valid until

17 Apr 15:00 UTC

Next update

17 Apr 15:00 UTC