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Avalanche danger forecast for
Friday 3/23/2018

AVALANCHE DANGER   wind slabs especially along the north-westerly borders and persistent weak layers difficult to recognize
Friday 3/23/2018

2000 m
The avalanche danger level is 3-considerable along the north-westerly borders with France and Switzerland, 2-moderate elsewhere. The avalanche problems are the wind-drifted snow and the persistent weak layers.

Artificial avalanche release:
- new windloads at the S and E aspects, above 2000 m, more widespread along the borders with France and Switzerland, where the wind activity is greater. They are slightly compacted and even medium sized. A single skier can trigger one of these slabs on the very steep slopes, mainly at entrance of gullies and close to ridges;
- persistent weak layers, able to generate slab avalanches even with a remote overload. Medium size with thickness between 30-60 cm. They are more common all over the region, mainly at the N and SE aspects, above 2300-2600 m. Low probability of a skier to intercept them, but the problem is difficult to identify. Tip: pay more attention along the backcountry tours not yet run across before during the winter season, even in flat or even not steep areas.

Natural avalanche release:slight rise in temperatures even at high altitudes, but not significant.
Some small / medium-sized loose or slow-release avalanches from rock bars and very steep, sunnier open slopes, especially below 2800-3000 m, mostly with the arrival of the sun. Below 2500 m few glide-snow avalanches from the very steep grassy/rocky slopes are possible.
Small / medium-sized surface slabs in leeward slope, where wind activity was more intense.

AVALANCHE DANGER TREND  Saturday 24:    Sunday 25:  

updated to 3/21/2018
  Today first day of springtime...not for the snowpack!
New snow and weather
Cold temperatures and moderate/strong wind keep the snowpack cold. Excellent night refreezing from the valley floor. Only on the sunniest slopes and in the most sheltered valleys the sun influences the snowpack, humidifying the surface layers during the hottest hours of the day below 2300-2900 m depending on the areas and the aspects. But at high altitudes and in shaded exposures, the cold will keep it still weak and dry.
Last night, a few cm of new snow were measured in the Gressoney Valley.
The wind is more intense along the northern borders of the region, moderate or strong from N. Accumulations have formed in the leeward areas and will continue to increase in the next few days. At high altitude (> 3300-3500) the wind is stronger and it has eroded the snowpack, discovering ridges and bumps. New cornices, both north and south, quite large.

Surveyed avalanche activity in the last 24h
Some natural releases reported, both loose snow type of small size from the very steep sunny slopes and rocky bars, even at high altitudes, and slab type, small to medium size.
Artificial release: last Monday reported a remote distance triggered avalanche of medium size, SE aspects, 2900 m (Cogne area). Still some reports of settling noises (whooms).

Snowpack stability
Along the ridge on the border with Switzerland, the wind is creating accumulations on the southern and eastern aspects, on steep slopes they will rest on crusts. Below 2500-2700 m the accumulations that are forming are localized and small/medium sized. The bond with the old snowpack surface is not optimal, especially on the slope changes and at the entrance of the gullies. At higher altitudes the accumulations are more widespread and larger. In both cases they are from soft to fairly compact, not yet hard. Above 3300-3500 m the wind action is very intense, ridges and bumps are completely eroded.
The problem remains the presence of persistent weak layers, very subtle and difficult to identify. At a depth varying from 30-60 cm, you can find facets under a crust or layers of surface hoar that, if stressed, can originate the release of slabs at distance.
The cold temperatures recorded above 2500-2600 m do not help to improve the situation, so the problem remains until there will be a significant rise in temperatures.
Below 2200 m of altitude, the basal layers of the snowpack are often damp/wet (typically spring crystals) close to the ground.

Snow cover:
- from absent to discrete up to 1500 m;
- excellent from 1900 m to 2800 m;
- good above 2800 m, but less homogeneous, with partly eroded ridges, north walls exposed to ice and bumps and filled gullies.
In the lateral valleys you can put on your skis right from the bottom of the valley.

Skiing conditions
Generally powdery snow, nice to ski above 2100-2300 m mostly on the northern slopes, in humidification below 2300-2500 m depending on the areas. In high mountains, different areas with snow drifted by the wind. On the south slopes thin melt and freeze crust up to 3100 m.
Weather forecast

EUROPEAN AVALANCHE DANGER SCALE Rising avalanche danger during the day

Snow and avalanche bulletin n° 112 issued on 3/22/2018 at 00:00 p.m.
Valid outside the ski runs controlled and managed by the ski resorts.
For an accurate interpretation of the Bulletin, a specific guide is available at AINEVA