| AVALANCHE DANGER |
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Suspect slopes: steep, large and homogeneous slopes, not skied before, exposed between NO, N and E, between 2400 and 2900 m |
Wednesday 2/22/2017
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The avalanche danger is 2-moderate on most of the region; 1-low in the southeast valley floor. The greatest danger is given by persistent weak layers and, minimally, by the wind-drifted snow.
Artificial avalanche release:
1 - persistent weak layers: one or more skiers may surcharge the inner weak layers and thus triggering slabs, even thick and extended (low probability of release, but, in case, with considerable consequences). The danger points are few, but hardly recognizable even by the expert. The suspects slopes, to be carefully evaluated, are the steep slopes, wide and homogeneous, colder aspects (NW, N and E) between 2400 and 2900 m, little skied earlier during winter.
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2 - wind-drifted snow: above 2600-2800 m there are new soft or hard accumulations, small sized (up to 20-30 cm of thickness), built up, and still in formation, by the moderate/strong winds from NW in act since the afternoon of Sunday, February 19 (prevailing aspects of the accumulations E, SE, S, easy to recognize).
Natural avalanche release: limited. Possible some snow avalanches and small slabs, even full-depth, on the steep slopes below 2700-2900 m, at the sunniest aspects.
Avalanche danger trend: gradually decreasing. |
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| AVALANCHE DANGER TREND |
Thursday 23: |
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Friday 24: |
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GENERAL CONDITION
updated to 2/21/2017 |
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The snow cover is poor in the middle mountain and really irregular at the highest altitudes, sometimes with eroded bumps and outcropping and hidden stones. The snow is very heterogeneous and the skiing quality is fairly good at all aspects and above 2200-2400 m, while at lower altitudes there is less snow, very traced and, at S aspect, also hardened by melt/freeze cycles.
The last days, with good sun and cold night, as well as those forecast during the current week, gradually contribute to improve the stability of the snowpack, especially on the sunny slopes where snow is slowly evolving toward spring conditions. In the morning on some steep southern slopes, up to 2800-3000 m, the crust is unbreakable, but during the hottest hours it becomes moist and it is already possible to ski on a great firn. Just changing a little bit the exposure and the slope angle the snow switches from spring to winter type. In fact, in the most shady and cold slopes (from NO to N and E) the low temperatures and the still poor sunlight fail to transform the snow surface which is still loose or wind-drifted. At the intermediate aspects, we also have thin crusts difficult to ski.
The inner layers are weak, formed by facets or depth hoar. The thickness of these layers varies from 10 to 60 cm and are located under 30-60 cm from the surface.
During the hottest hours of the weekend there were some natural releases of humid snow, especially on the steep slopes and from the rock walls. |
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| EUROPEAN AVALANCHE DANGER SCALE |
 Rising avalanche danger during the day |
|  | 5 | VERY HIGH |
|  | 4 | HIGH |
|  | 3 | CONSIDERABLE |
|  | 2 | MODERATE |
|  | 1 | LOW |
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| TYPICAL AVALANCHE PROBLEMS |
CRITICAL LOCATIONS |
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| NEW SNOW |
WIND-DRIFTED SNOW | PERSISTENT WEAK
LAYERS |
WET SNOW |
GLIDING SNOW |
IN BLACK: THE MORE CRITICAL ASPECTS AND ELEVATIONS |
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Snow and avalanche bulletin n° 90 issued on 2/21/2017 at 00:00 p.m.
Snow and avalanche bulletin n° 90 issued on 2/21/2017 at 00:00 p.m.
Valid outside the ski runs controlled and managed by the ski resorts. |
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For an accurate interpretation of the Bulletin, go here
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