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Avalanche danger forecast for
Friday 3/16/2018


 

AVALANCHE DANGER   New slabs at N-E-SE exposures.
Friday 3/16/2018
  

1800 m

  
The avalanche danger level is 3-considerable throughout the region.
The main avalanche problems are wind drifted snow and fresh snow. Spontaneous avalanche activity more intense during the hottest hours of the day.

Triggered avalanches.
- new wind accumulations of small to medium size, generally soft and sensitive to the passage of the individual skier above 2300-2600 m in the western sectors bordering with France and in the sectors to the north on the border with Switzerland. They are located on the eastern and southern slopes under the ridges, near the hills and on slope changes. At the highest altitudes and mainly in the ridge area, they are also present at the northern exposures and in the sectors bordering Piedmont;
- old wind accumulations above 2500 m on steep slopes at all exposures (especially north and south-east). They are thick from 50 cm to 1 m, they can be triggered with heavy overload near the ridges and on the slope changes and at the entrance of the gullies.They are more widespread in the west of the region, they decrease moving to the east where they are present mainly at high altitudes.
Aggravating factor: the fresh snow covered the old slabs, for which a conservative attitude is recommended in off-piste activities.

Spontaneous avalanche activity:
- sluffs and small and medium loose-snow avalanches of fresh snow and slabs above the forest limit at all exposures. Possible also some bottom slabs from very steep grassy/rocky slopes, in the hottest hours of the day.
- Above 2500 m, especially in the west of the region, there is a lot of recent snow with weak cohesion: the additional overload by fresh snow and wind drifted snow transported by the SO moderate wind, could facilitate dry snow natural avalanches of medium size.

AVALANCHE DANGER TREND  Saturday 17:    Sunday 18:  
Constant with new snowfall and decreasing temperatures.

GENERAL CONDITION
updated to 3/15/2018
 
Fresh snow : 5-15 cm on Thursday morning, continues in the afternoon with weak snowfall, locally moderate in the upper valley and on the border with Piedmont.

The spontaneous avalanche activity was important on Tuesday and Wednesday.Many natural loose snow avalanches and slabs at all expositions above 2200 m. Some large slab avalanches of dry snow that in the descent have hooked wet/very wet snow at lower altitudes. Several surface slabs triggered with weak overload on the north and southeast slopes at 2500 m. The sliding planes are: recent snow with weak cohesion, surface hoar and levels of freze-melt crusts with faceted crystals.

Snowpack stability
Excellent refreeze in the morning. Maximum temperatures rising during the day.
The sun humidifies the snow up to 2500-2800 m depending on the exposures: the snowpack in the day becomes wet or wet up to 30 cm deep.
 The March sun is strong, touches all the slopes warming them strongly, even the northern ones remained long cold, so the stability changes quickly. To make the picture worse the type of snow that characterizes the most superficial layers: several layers of overlapped wind drifted snow (at high altitude) or loose snow on weak layers at N or on melt and freeze crusts. It is therefore an unconsolidated snow on preferential sliding or breaking surfaces. Moreover above 2500 m the wind from SO, O and NO has loaded the slopes at all the exposures, in particular the N, E and S. So above the 2500 m there are soft slabs that will be partly masked by the fresh snow of Thursday and new accumulations for moderate SO and NW winds.

Snowcover:
- 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 2000-2200 m in humidification below 2500 m. In high mountains, different areas with snow re-worked by the wind. The fresh snow is not always sufficient to cover the old traces, on the southern slopes laying on a melt and freeze crust up to 2500 m.
Weather forecast

SNOW AND WEATHER CONDITIONS OF THE 7 LAST DAYS  
Monte Bianco Gran San Bernardo Gran Paradiso Monte Rosa

EUROPEAN AVALANCHE DANGER SCALE Rising avalanche danger during the day
 
5
VERY HIGH
 
4
HIGH
 
3
CONSIDERABLE
 
2
MODERATE
 
1
LOW

TYPICAL AVALANCHE PROBLEMS   CRITICAL LOCATIONS
NEW SNOW
WIND-DRIFTED SNOW
PERSISTENT WEAK
LAYERS
WET SNOW
GLIDING SNOW
IN BLACK: THE MORE CRITICAL ASPECTS AND ELEVATIONS
Snow and avalanche bulletin n° 105 issued on 3/15/2018 at 00:00 p.m.
Valid outside the ski runs controlled and managed by the ski resorts.
For an accurate interpretation of the Bulletin, go here