Avalanche bulletin and weather forecast Haute Savoie

This avalanche translation of the Meteo France avalanche bulletin is produced mainly through an automated translation tool. Please use it in conjunction with the French bulletin found at the above link.

N74191211
BULLETIN FOR ESTIMATE OF AVALANCHE RISK - HAUTE SAVOIE
Valid off marked trails and open
FOR THURSDAY 20 DECEMBER 2007
(Drafted Wednesday, December 19)

ESTIMATE OF RISK UNTIL THURSDAY EVENING:
All masses - Haute Savoie: Limited risk (level 2).

WEATHER OVERVIEW UNTIL THURSDAY EVENING:
Good weather, with a few softer gusty foehn in the Mont Blanc.

Isothermal 0 DG: 2200 m with inversion temperatures at low altitudes.
Isothermal -10 DG: 3900 m
Wind at 2000 m: Slow of Southeast gusty foehn at the foot of Mont Blanc.
Wind at 4000 m: Southeast 70 km / h.

SNOW CONDITIONS:
They are excellent for mid-December, with a base like at high altitude! We can ski from 800 meters in northern slopes, about 1000 m in the south. At altitude, we find significant variations in the thickness of  the snow due to winds that have been blowing hard in all different directions. Attention all the same with snow bridges that can still be fragile on the lower parts of the glaciers.

Quality of snow for Thursday:
On average, the mountain has predominately a good old powdery snow in particular at low altitude with ice surface, except in the southern slopes where snow is transformed croûtée in the morning then a little wet in the afternoon. At high altitudes in the Mont Blanc massif, as well as in some other areas of massive exposed to wind, snow, but not powdery or cardboard hard by the wind with a not very pleasant ski.

STABILITY OF SNOW COVER:
Some wind slabs aloft and a small activity avalancheuse due to melting.

After a week of good weather, the snow is now well stabilized as a whole with a few nuances.

At the risk of triggering a slab avalanche with the passage of a skier, it is well located to an average of mountain peaks, where the snow was blown. Possible slabs are few on average on the mountain. In the high mountains, in the Mont Blanc, the risk of wind slabs is probably more important, but perhaps slabs are more difficult to break.

With the rebound, there will be small avalanche activity on average on natural mountain slopes in the more or less south. Indeed, in a very steep slope after several hours of sunshine, a few wet snow avalanches could start spontaneously beating most often as the snow surface. The passage of a skier could facilitate the departure of this type of avalanche cutting a steep ski slope heavily exposed to the sun.
On the other hand, still in a very steep slope south-east to south-west, it is still possible, but quite rare for a spontaneous avalanche outweighs any snow to the ground if the ground is grassy or has rock slabs.

TREND SUBSEQUENT RISK:
Without major change by the end of the week, maybe slightly down this weekend.

Météo updates this newsletter everyday at 16h or earlier if conditions nivométéorologiques warrant.