Wet snow avalanches also occur at altitude during daytime changes
The avalanche risk is already considerable below around 2500 metres in the morning and below around 3000 metres in the afternoon. Wet slab avalanches and loose snow avalanches are to be expected on slopes that have not yet been unloaded. This is in those aspects where there is still a lot of snow, i.e. also on the south side at high altitudes. Most avalanches occur naturally, but wet slab avalanches can also be triggered by winter sports. Remote triggering is possible in isolated cases. Avalanches can become large in some places as wet snow collects and tears through the persistent weak layer and can reach unusually long run-out lengths. Caution should also be exercised in the apery areas of trenches. There are isolated signs of sliding snow activity.
In a few places above 2400 m, weak layers can also be disturbed directly in the persistent weak layer, especially on west, north and east-facing slopes, and also on the south side in the high Alps. Snow slabs in the dry persistent weak layers remain predominantly medium sized.
Strong southerly foehn winds deposited small pillows of wind drifted snow in high gullies and bowls on Monday, which are locally covered with a few centimetres of new fallen snow and are difficult to recognise.
Snowpack
The snowpack cools down poorly overnight, only in some areas a thin melt-freeze crust forms, which soon softens. There is compact snow underneath, but softer layers are embedded, especially at higher altitudes, which allow breaks near the surface. On shady slopes from around 2400 metres, there are still weak layers of angular forms and deep rime in the old snowpack close to the ground. The snowpack becomes moist to wet up to high altitudes during daytime changes at the latest. Low and sunny slopes are covered in snow.
Tendency
Progressive soaking of the remaining snowpack.
EARLIER Danger level
2500m
Avalanche Problem
Wet snow
2500m
Persistent weak layer
2500m
LATER Danger level
2800m
Avalanche Problem
Wet snow
2800m
Persistent weak layer
2500m
Naturally triggered avalanches expected during course of day
Dangerous avalanche situation widespread during daytime. Main danger: wet snow.
Due to starkly reduced nocturnal outgoing radiation in many places, the snowpack is hardly freezing except in high alpine regions. Below about 2500m the snowpack is softened already in early morning and persons can trigger wet-snow slab avalanches. As a result of daytime warming and solar radiation, frequency of avalanche prone locations rapidly increases so that during afternoon, numerous naturally triggered wet-snow avalanches can be expected in all aspects below about 2600m, above that altitude on sunny slopes. Caution urged above all on steep shady slopes at 2200-2600m, where wet-snow avalanches can fracture in the weak old snow and grow to large size, in isolated cases also in freeriding terrain which has been heavily tracked and skied. Avalanches can plummet into steep gullies down to forested areas. Backcountry tours and ascents to refuges need to be launched early in the day and brought to a close early. In addition, winter sports enthusiasts can in isolated cases trigger avalanches in near-surface weak layers on high-altitude shady slopes. Such danger zones are impossible to recognize.
Snowpack
Following starkly reduced outgoing radiation, the snowpack is hardly freezing at night. At altitudes of 1800-2500m the ground level layer of rotten snow is thoroughly wet, even on north-facing slopes, and is prone to triggering. On high-altitude shady slopes there are unfavorable intermediate layers in the uppermost layer of the snowpack which in places can be triggered. A thick mid-section of compact layers blankets the deep hoar and faceted crystals at the base of the snowpack.
Tendency
On Wednesday night, reduced outgoing longwave radiation is again anticipated. Gradually, high-pressure front conditions with mild temperatures will prevail. The snowpack surface barely freezes and rapidly softens in the morning. Due to daytime warming and solar radiation, danger of wet-snow avalanches increases during daytime hours.
Danger level
Avalanche Problem
Wet snow
Wet-snow danger in very steep terrain where there is still lots of snow
Persons can trigger wet-snow avalanches in very steep terrain. Danger zones generally occur only in summit zones of the Bregenzerwald mountains. Avalanches generally remain medium-sized. On steep, smooth-ground slopes with lots of snow which have not yet discharged, glide-snow avalanches can trigger in all aspects.
Snowpack
Due to reduced nocturnal longwave outgoing radiation and ongoing mild temperatures, the snowpack does not freeze at night. At all altitudes the snowpack is thoroughly wet.
Tendency
On Wednesday night, reduced outgoing longwave radiation is again anticipated. Gradually, high-pressure front conditions with mild temperatures will prevail. The slopes are continually becoming bare of snow.
Danger level
Avalanche Problem
Wet snow
Persistent weak layer
2200m
Wet snow avalanches detach up to the summit areas
The avalanche risk is moderate. Wet loose snow and slab avalanches are already possible in the morning on slopes that have not yet been unloaded, with the danger increasing again slightly in the afternoon. This is in those aspects where there is still a lot of snow. Avalanches can occur naturally or be triggered by winter sports. They usually remain medium in size, but with the accumulation of wet snow and tearing through to weak layers close to the ground, large avalanches are conceivable in exceptional cases. Caution should also be exercised in the shallow outlet areas of trenches. Small gliding sluffs are occasionally recorded.
Trigger points for dry old snow avalanches are only present at a few high points in the extended northern sector.
Snowpack
The snowpack cools down poorly overnight, only in some areas a thin melt-freeze crust forms, which softens quickly. Underneath is compact snow, but on shady slopes from around 2200 metres there are still weak layers of deep rime in the old snowpack near the ground. The snowpack will become moist to wet up to high altitudes during the daytime changes at the latest. Low and sunny slopes are snowed out.
Tendency
Progressive soaking of the remaining snowpack.
Danger level
Avalanche Problem
Wet snow
Persistent weak layer
2200m
Watch out for wet snow problems - all day!
The avalanche risk is predominantly moderate at altitudes where there is still a sufficiently thick snowpack. Spontaneous or occasional wet snow avalanches triggered by people are possible at any time from undischarged steep terrain in all aspects up to higher altitudes. Only high alpine and on shady slopes could slab avalanches be triggered in very steep terrain by large additional loads.
Snowpack
The snow surface can hardly firmness overnight. The snowpack continues to break down, is wet up to high altitudes in the centre and otherwise damp and therefore unstable. Mild temperatures and occasional rain showers further destabilise the snowpack. Only high up and on shady slopes can there still be isolated weak layers in the old snowpack. Low and sunny slopes in the middle of the mountain are bare.
Tendency
Little change.
Danger level
2200m
Avalanche Problem
Wet snow
2200m
Persistent weak layer
1800m
Gliding snow
Rain thaw below 2200 m, possibility of triggering gliding avalanches.
The old snow cover is mostly well connected and generally stable.
Rainfall below 2200 reduces snowpack stability. Where rainwater reaches the thinned layers, natural wet snow avalanches may be triggered.
Gliding avalanches may be triggered.
Snowpack
dp.10: springtime scenario
In an old snow cover, the snow layers are mostly well connected. More or less deep below the surface, there are several weak layers of shreds and discontinuous grains, which are more frequent on slopes at the axis.
On a cloudy night, the surface of the snowpack will not freeze.
There will be some light precipitation on Tuesday evening, with rain softening the upper layers of the snowpack below an altitude of about 2200 m. Where the rain reaches the thinned layers, slightly deeper and larger wet snow avalanches may be triggered. A few centimetres of New fallen snow will fall above 2200 m.
Tendency
Thursday will be mostly sunny, with possible showers in the afternoon. Friday will be sunnier and drier. It will remain warm.
Danger level
Avalanche Problem
Wet snow
Persistent weak layer
2200m
Moderate avalanche danger, wet snow problem all day long!
The avalanche risk is moderate. In a few places, small to medium-sized, wet loose snow and slab avalanches can be triggered by themselves or by slight additional load throughout the day from terrain that has not yet been discharged. In a few extremely steep, shady areas above 2200 m, small to medium-sized dry slab avalanches can still be triggered.
Snowpack
During the night, the snowpack can hardly consolidate and remains isothermal and soft up to high altitudes. The soaking can reactivate old weak layers in the persistent weak layer, especially on the north side. In all aspects, the soaked snowpack can lose its stability or begin to glide on smooth ground. At low altitude and on the sunny slopes, the snow cover is developing rapidly.
Tendency
On Thursday and Friday there will be longer sunny spells overall, but the classic April weather will not be completely stable and there will be showers at times.
Danger level
Avalanche Problem
Wet snow
Wet-snow danger in very steep terrain where there is still lots of snow
Persons can trigger wet-snow avalanches in very steep terrain. Danger zones generally occur only in summit zones of the Bregenzerwald mountains. Avalanches generally remain medium-sized. On steep, smooth-ground slopes with lots of snow which have not yet discharged, glide-snow avalanches can trigger in all aspects.
Snowpack
Due to reduced nocturnal longwave outgoing radiation and ongoing mild temperatures, the snowpack does not freeze at night. At all altitudes the snowpack is thoroughly wet.
Tendency
On Wednesday night, reduced outgoing longwave radiation is again anticipated. Gradually, high-pressure front conditions with mild temperatures will prevail. The slopes are continually becoming bare of snow.
Danger level
1500m
Avalanche Problem
Wet snow
1500m
Wet snow
1500m
Progressive deaperisation
The avalanche risk is moderate above 1500 metres and low below that. Wet snow is problematic. Wet loose snow and slab avalanches are to be expected, especially at high altitudes where there is still a lot of snow. In extremely steep terrain in all aspects of the slope, they detach themselves; on very steep slopes, they can be triggered by individuals. On steep slopes with smooth ground, such as on meadow slopes, in patchy mountain forests or on smooth rock slabs, wet gliding avalanches occur. Avalanches reach medium size.
Snowpack
The snowpack is soaked up to high altitudes. At higher altitudes, there are a few centimetres of soft, moist snow on a largely stable and, on shady slopes in particular, still thick old snowpack. In places, layers of faceted crystals have been preserved deeper in the snowpack at high altitudes exposed to the north. On the south side, the ground is already bare again above the tree line.
Tendency
Little change.
Danger level
Avalanche Problem
Wet snow
Small wet-snow slides possible
Persons can trigger wet loose-snow avalanches in steep terrain where there is sufficient snow on the ground. Avalanches will be mostly small-sized.
Snowpack
The ground is largely bare of snow. Where there is a snowpack, it is thoroughly wet.
Tendency
Gradually, high-pressure front conditions with mild temperatures will prevail. The slopes are continually becoming bare of snow.
Danger level
Avalanche Problem
Wet snow
Small wet-snow slides possible
Persons can trigger wet loose-snow avalanches in steep terrain where there is sufficient snow on the ground. Avalanches will be mostly small-sized.
Snowpack
The ground is largely bare of snow. Where there is a snowpack, it is thoroughly wet.
Tendency
Gradually, high-pressure front conditions with mild temperatures will prevail. The slopes are continually becoming bare of snow.
Danger level
Avalanche Problem
Wet snow
Low avalanche danger, occasional small wet snow slides possible
The avalanche risk is low. Small wet snow slides can occur occasionally in all aspects, especially from multiple starting zones that have not yet been fully discharged. The risk of entrainment in the fall terrain outweighs the risk of burial.
Snowpack
The thin, mostly isothermal snow cover cannot consolidate overnight and continues to soak through during the day. There is only a little snow left and the sunny slopes are usually already snowed out.
Tendency
On Thursday and Friday there will be longer sunny spells overall, but the classic April weather will not be completely stable and there will be showers at times.
Danger level
Avalanche Problem
Wet snow
Small wet snow avalanches in snowy places
The avalanche risk is low. Small wet snow slides can spontaneously occur from slopes that have not yet been unloaded on those aspects where there is still snow. Wet snow slides triggered by winter sports increase the risk of entrainment in the fall terrain.
Snowpack
The outgoing longwave radiation at night is poor and the snow cover remains largely isothermal. Small pillows of wind drifted snow can still be found adjacent to ridgelines in places, but most of the terrain is already snowed out.
Tendency
Gradual reduction of the avalanche risk due to melting and raining away of the remaining snow.
Danger level
Avalanche Problem
Wet snow
Increasing snow cover also on the north side
The avalanche risk is low. Wet snow is problematic. In extremely steep terrain, loose snow avalanches can occasionally come loose. Wet gliding avalanches can occur on steep slopes with smooth ground that have not yet been discharged. Avalanche activity is limited to terrain on shady slopes where there is still snow. Wet avalanches usually remain small.
Snowpack
The remaining snowpack is completely soaked, the meltwater runoff hardly decreases even overnight. The southern sides are largely snowed out.
Tendency
The avalanche danger remains low.
Danger level
Avalanche Problem
Wet snow
Local wet snow problem!
The avalanche risk remains predominantly low. On higher steep slopes with a sufficiently thick snowpack, localised wet snow avalanches are possible during the day in all aspects, some of which can reach medium size.
Snowpack
The snow surface can hardly firmness overnight. The snowpack continues to break down, is wet up to high altitudes on the inside, otherwise damp and therefore unstable. Some sunshine and occasional rain showers further destabilise the snowpack. Low and sunny slopes in the middle of the snowpack are bare.
