Slab avalanches in the snowdrifts can fracture down to deeper weak snowpack layers
Avalanche danger above the treeline is considerable, below that altitude danger is low. Snowdrift accumulations are the main problem. Slab avalanches of medium size can in some places b e triggered even by minimum additional loading, i.e. the weight of one person. In some places above 2200m they can fracture down to deeper weak layers in the old snow and thereby grow to large size. Danger zones can be difficult to recognize due to diffuse light conditions. They occur also distant from ridgelines and on slopes in NW/N/SE aspects. On the Main Alpine Ridge, danger. zones occur in all aspects. In some places, the snowdrifts have been blanketed over, making them difficult to recognize.
Snowpack
The fresh fallen snow has been heftily transported. Inside the fresh snow, short-lived weak layers are forming near the surface. At high altitudes the fresh snow is falling atop a generatlly wind-compressed snowpack surface where the bonding is good. IAbove 2000m the fresh snow and drifts have often been deposited atop faceted crystals near crusts, in some places surface hoar has been blanketed on shady, wind-protected slopes above the treeline. Deeper down inside the old snowpack fundament there are soft layers lodged between hard layers at high altitudes. At low and intermediate altitudes the old snowpack beneath the fresh fallen snow is melt-freeze encrusted. The entire snowpack can start to glide over steep rock plates or grassy slopes.
Tendency
On Sunday, fresh snowfall and winds will lead to increasing avalanche danger levels.
Danger level
treeline
Avalanche Problem
Wind slab
Treeline
New snow
Snowpack
Tendency
Danger level
treeline
Avalanche Problem
Wind slab
Treeline
Persistent weak layer
2200m
Fresh snowdrifts are the main danger
Avalanche danger above the treeline is considerable, below that altitude danger is low. Snowdrift accumulations above the treeline can be easily triggered even by one single winter sports enthusiast and grow to medium size. Slab avalanches can often fracture down to more deeply embedded layers inside the snowpack and grow to large size. Danger zones occur particularly behind protruberances in the landscape, in gullies and blows and on wind-loaded slopes. These have been covered by fresh snow in many places, making them difficult to recognize. Whumpf noises and glide-cracks when the snowpack is stepped on are signals of danger. At low and intermediate altitudes on steep grass-covered slopes, small glide-snow avalanches are possible.
Snowpack
Since yesterday there has been 40-45cm of fresh snow registered in the barrier cloud regions, elsewhere 25-30cm. Due to strong-to-storm strength W/NW winds there has been wide-reaching transport. During the daytime due to brisk-to-strong NW winds, and tomorrow W/SW winds, additional trigger-sensitive snowdrift accumulations have been generated and will continue to be. The drifts lie deposited atop a weak old snowpack on high-altitude shady slopes, on sunny slopes often atop a thin melt-freeze crust. Weak layers can occur on high altitude slopes where the old snowpack was previously loose and also inside the snowdrifts themselves. During the daytime, in addition, graupel showers will pass through. At low altitudes the fresh snow and drifts lie deposited atop a moistened old snowpack surface with better consolidation.
Tendency
Following a brief improvement in weather conditions on Saturday, renewed preciptiation will set in during Saturday night, accompanied by strong-to-storm strength W/NW winds. Avalanche danger levels are expected to increase significantly over widespread areass.
Avalanche danger levels above the treeline are moderate, below that altitude danger is low. Snowdrifts are the major problem. Slab. avalanches of medium size can be triggered even by minimum additional loading, particularly near to ridgelines on N/E/SW facing slopes. Danger zones are difficult to recognize due to diffuse light conditions.
Snowpack
The fresh fallen snow has been heftily transported. Inside the fresh snow, short-lived weak layers are forming near the surface. At low and intermediate altitudes the old snowpack is generally well consolidated. Above 2000m the fresh snow and drifts are often faceted near crusts. In some places on shady wind-protected slopes above the treeline, surface hoar has formed. The entire snowpack can glide over steep rock plates or grassy slopes.
Tendency
On Sunday, fresh snowfall and winds will lead to increasing avalanche danger levels.
