Snowdrifts and weak layers in old snow on shady slopes, slight daytime cycle of wet-snow avalanche activity
Fresh snow and snowdrift accumulations on shady wind-protected slopes often lie deposited atop surface hoar. Winter sports enthusiasts can trigger avalanches, particularly by large additional loading on very steep shady backcountry slopes. These avalanche prone locations occur most of all in spots where the snow is shallow and in transitions from shallow to deep snow. If avalnaches fracture down to deeper-down layers of the snowpack, they can in isolated cases grow to large size. During the course of the day, natural triggerings of small-sized wet-snow and glide-snow avalanches are possible, particularly on steep sunny slopes.
Snowpack
Above about 1500m there has been about 10cm of fresh fallen snow, in Verwall and in Sllvretta somewhat less, below that altitude there was rainfall. The fresh snow lies deposited on sunny slopes atop a barely frozen, generally softened up surface, on shady slopes frequently atop surface hoar or a hard rain crust. The mid-level part of the snowpack consists widespread of well settled, compact layers which on shady higher-altitude slopes cover a poorly-structured old snowpack fundament.
Tendency
Avalanche danger will increase far-reachingly starting at noon on Saturday, due to fresh snowfall and wind.
Danger level
1900m
Avalanche Problem
Persistent weak layer
1900m
Wet snow
1900m
Weak layers persist deep in the snowpack
The problem is the weak layers in the snowpack, which are deeper in the snowpack. If the load exceeds the load-bearing capacity of the deeper Weak layers, a deep and large avalanche can be triggered. There are many such weak layers, especially on axis above the forest. Small wet snow avalanches are possible during the day on sunny slopes.
Snowpack
dp.1: deep persistent weak layer
The snow has settled and, especially on the Sunny slopes, has already transformed quite well. Layers of snow have bonded together and the surface is crusty in many places. Several weak layers of faceted snow crystals and coarse grains are found deep below the surface in the old snow cover.
Tendency
It will clear up on Tuesday. Faster in the high alpine regions than in the mid mountains. There will be no major warming. The danger of avalanches will remain similar.
Danger level
1800m
Avalanche Problem
Persistent weak layer
1800m
Weak persistent layer is a persistent weak layer
The avalanche risk is moderate above 1800 metres and low below. There is still a persistent weak layer problem in the extended northern sector. Medium-sized slab avalanches can still be triggered by people in steep gullies and bowls. The avalanche prone locations are usually difficult to recognise and are often located in transition areas from little to much snow.
The probability of triggering wet snow avalanches increases slightly during the daytime changes from very steep east- to south- to west-facing slopes.
In steep terrain, there is a risk of falling on the hard snow surface.
Snowpack
Outgoing longwave radiation is somewhat reduced from the second half of the night. As a result, the snow surface can often only consolidate weakly and soften increasingly on the sunny slopes depending on the incoming radiation. On shady slopes, there are still areas with a soft (faceted) snow surface at higher altitudes, where the firmness of the layer changes depending on the altitude and exposure. Below this there is an increasingly sufficiently settled and compact snowpack, the transition to the foundation consisting of deep rime (floating snow) is still poor. Medium (sunny slopes) and low altitudes are largely free of snow.
Tendency
Quite sunny and dry on Friday and Saturday. With a wind shift to the south-west, it will be partly foehn. Little change in avalanche danger.
Danger level
2000m
Avalanche Problem
Wind slab
2000m
Wet snow
Snowdrifts on shady slopes, slight daytime cycle of wet-snow avalanche activity
Fresh snow and snowdrifts lie deposited atop surface hoar on a wind-protected, high-altitude shady slopes. Winter sports enthusiasts can trigger generally small-sized avalanches. Apart from being buried in snow masses, the risks of being swept along and forced to take a fall require special caution. During the course of the day, natural triggerings of small-sized wet-snow and glide-snow avalanches are possible, particularly on steep sunny slopes.
Snowpack
Above about 1500m there has been about 10-15cm of fresh snow regionally, below that altitude there was rainfall. The fresh-fallen snow lies deposited on sunny slopes atop a barely frozen, generally softened up surface, on shady slopes frequently atop surface hoar or a hard rain crust. The mid-level part of the snowpack consists widespread of well settled, compact layers which on shady higher-altitude slopes cover a poorly-structured old snowpack fundament. No triggerings in this weak layer of the snowpack were further registered at the Avalanche Warning Service headquarters last week.
Tendency
Avalanche danger will increase widespread starting at noon on Saturday, due to fresh snowfall and wind.
Danger level
2000m
Avalanche Problem
Persistent weak layer
2000m
Few avalanche prone locations with high consequences
The avalanche risk is moderate above around 2000 metres and low below. In a few places, especially in the aspects from west to north to east, medium, occasionally still large, dry slab avalanches can be triggered by individuals. Danger areas are difficult to recognise. Take particular care at the transitions from little to more snow.
Occasional wet snow avalanches triggered by people on the sunny slopes with soaking of the snowpack are possible. The likelihood of gliding avalanches is slightly increased.
Snowpack
Only a few centimetres of new fallen snow fell, below around 1700 m it rained lightly. In shady high altitudes, soft, faceted snow can often still be found on the surface. In most cases, however, the surface is at least just crust can form. Below this lies a well-set sequence of compact drift snow layers, in which a crust is embedded in combination with faceted crystals. The connection at the transition to the old snow foundation, which consists mainly of deep rime, is still poor. Deep and sunny middle layers are largely snowed out.
Tendency
No significant change in avalanche danger despite strong foehn on Saturday.
Danger level
1800m
Avalanche Problem
Persistent weak layer
1800m
Be aware of the persistent weak layer problem!
The avalanche risk is predominantly moderate above 1800 metres. There are still avalanche prone locations on shady slopes in steep terrain. Here and at the transition from little to more snow, isolated slab avalanches can be triggered by mostly large additional loads. Individual spontaneous wet snow avalanches are possible from unloaded steep slopes.
Snowpack
Rain showers and some new fallen snow above around 1200 metres until the afternoon. The new fallen snow will fall on a barely stabilized, partly crusted, otherwise often up to high altitudes moist or wet old snowpack. The snow base, fundament remains high and weakened on the shady slopes due to the kinetic metamorphism. At low altitude or sunny slopes, the snow cover remains bare or slightly "sugared".
Tendency
Little change.
Danger level
2000m
Avalanche Problem
Persistent weak layer
2000m
Wet snow
Persistent weak layer problem: Be careful at transitions from a little to a lot of snow.
The avalanche risk is low. Persistent weak layers are the main problem. The few avalanche prone locations are mainly in the northern aspects of the high altitudes on very steep slopes and at the entrance to gullies and bowls. Slab avalanches can be triggered with a large additional load and can reach medium size.
With the sunlight, individual, smaller loose snow avalanches also release themselves from the rocky steep terrain. At medium altitudes, individual small to medium-sized gliding avalanches are possible on slopes with a smooth surface.
Snowpack
In shady high altitudes, layers of faceted crystals can be found deep under a compact snowpack and in some places close to the surface under a thin melt-freeze crust. In the Allgäu in particular, there are a few centimetres of mostly slightly damp new fallen snow on the melt-freeze crust. Where the snow is still dry, it can be transported by the wind. Otherwise, the new fallen snow is well bonded to the old snow surface. It loses its bond with the sunlight. At medium altitudes, the snowpack is wet towards the ground. There is hardly any snow at low altitudes.
Tendency
Changeable weather can lead to a slight increase in avalanche danger.
Danger level
Avalanche Problem
Wet snow
On the south side, the ground is increasingly pitting up to the summits.
The avalanche risk is low. Wet snow is the main problem. In particular, small loose snow avalanches can detach themselves from the rocky steep terrain in the sunlight. Smaller gliding avalanches are possible on individual, very steep slopes with smooth ground.
On very steep north-facing slopes at higher altitudes, small slab avalanches can also be triggered with a large additional load. This is particularly the case at transitions from a little to a lot of snow.
Snowpack
The night is generally clear. Early in the morning, the snow surface is still frozen hard. It softens relatively quickly with the sunlight. The surface snow loses firmness. Occasionally, weak layers of faceted crystals can be found deep under a compact snowpack on the shady slopes of higher summits and areas adjacent to the summit. The snowpack is otherwise moist to wet. There is hardly any snow at low altitudes.
Tendency
The avalanche danger remains low.
Danger level
Isolated wet snow avalanches!
The avalanche risk is predominantly low. Sporadic spontaneous wet snow avalanches are possible from unloaded steep slopes. There are still isolated avalanche prone locations on shady slopes in steep terrain where slab avalanches can be triggered by large additional loads.
Snowpack
Rain showers and some new fallen snow above around 1200 metres until the afternoon. The new fallen snow will fall on a barely stabilized, partly crusted, otherwise often up to high altitudes moist or wet old snowpack. The snow base, fundament remains high and weakened on the shady slopes due to the kinetic metamorphism. At low altitude or sunny slopes, the snow cover remains bare or slightly "sugared".
Tendency
Little change.
Danger level
Low avalanche danger
The avalanche risk is low. Wet snow slides can occasionally be triggered by people on steep slopes. Small slab avalanches are still possible in persistent weak layers on shady slopes. In general, the risk of falling and injury clearly outweighs the risk of burial. Be careful in partly icy, steep gullies.
Snowpack
The second half of the night is usually clear, so a melt-freeze crust forms, which softens again during the day with the sunlight and the rise in temperature. On shady slopes, the melt-freeze crust can last longer. In gullies and bowls, the wind slab is well stabilised, but in some narrow places it is icy. Faceted crystals are partially weakening the snow base, fundament at higher elevations in the northern sector. There is only a little snow below 1400 metres and below 1600 metres on sunny slopes.
Tendency
The avalanche danger remains low. Saturday will be foehn and quite sunny. However, the south wind will be strong to stormy at higher altitudes. More clouds will gather on Sunday and it will start to cool down. The coming week will then bring changeable and much cooler weather.
Danger level
1800m
Avalanche Problem
Persistent weak layer
1800m
Latent persistent weak layer problem, slightly increasing wet snow problem
The avalanche risk is low. Nevertheless, there is still a persistent weak layer problem in the extended northern sector. Occasionally, mainly in very steep gullies and bowls, slab avalanches can be triggered by people. The avalanche prone locations are usually difficult to recognise and are often located in transition areas from a little to a lot of snow.
On sunny slopes, incoming radiation increases the probability of triggering small wet snow avalanches.
In steep terrain, there is a risk of falling on the hard snow surface.
Snowpack
With outgoing longwave radiation, a melt-freeze crust can form, which softens on the sunny slopes during the day with increasing moisture penetration. On shady slopes at higher altitudes, there are still isolated areas with a soft (faceted) snow surface, where the firmness of the layer changes depending on altitude and exposure. Below this there is an increasingly sufficiently settled and compact snowpack, the transition to the foundation consisting of deep rime (floating snow) is still poor. Medium and low altitudes are often free of snow.
Tendency
Quite sunny and dry on Friday and Saturday. With a wind shift to the south-west, it will be partly foehn. Little change in the avalanche danger.
Danger level
1800m
Avalanche Problem
Persistent weak layer
1800m
Note the persistent weak layer
The avalanche risk is low. Medium-sized slab avalanches can still be triggered in a few hard-to-recognise places, especially in the extended northern sector above 1800 m, but usually only with a large additional load. This is in particular at the transitions from little to more snow.
On the sunny slopes, isolated wet snow avalanches are possible as the snowpack softens. These usually remain small.
Snowpack
Only a few centimetres of new fallen snow fell, below around 1700 m it rained lightly. In shady high altitudes, soft, faceted snow can often still be found on the surface. In most cases, however, the surface is at least just crust can form. Below this lies a well-set sequence of compact drift snow layers, in which a crust is embedded in combination with faceted crystals. The connection at the transition to the old snow foundation, which consists mainly of deep rime, is still poor. Deep and sunny middle layers are largely snowed out.
Tendency
No significant change in avalanche danger despite strong foehn on Saturday.
Danger level
Low risk of isolated wet snow avalanches
The avalanche risk is low. Occasional small wet snow avalanches are possible on the few sunny slopes that have not yet been discharged.
In addition, small snow slabs can still be triggered in exceptional cases in the entrance areas of steep gullies on shady slopes with large additional loads. The risk of being swept away and falling on icy surfaces generally outweighs the risk of burial.
Snowpack
Low and sunny mid-altitude areas are snowed out. Where present, the snowpack is moist to wet and well-settled right up to the summit areas. The snowpack radiates overnight and in some areas the surface becomes icy. In the higher, on shady slopes, there are still weak layers of large faceted crystals in the lower part of the snowpack, especially near the ground.
Tendency
No significant change in avalanche danger despite strong foehn on Saturday.
