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.

N74270211
BULLETIN FOR ESTIMATING THE RISK OF AVALANCHES
FOR HAUTE SAVOIE
Valid off marked and open trails
FOR THURSDAY 28 FEBRUARY 2008
(Drafted Wednesday, February 27)

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

WEATHER OVERVIEW UNTIL THURSDAY EVENING:
The next night, and Thursday, the sky will be shrouded by high clouds between 5000/3000 m, but the sun filter more or less Thursday through the cloud layer, in a fresh atmosphere.

Isothermal 0 2200 m.
Wind at 2000 m: Southwest 10/20 km / h.
Wind at 4000 m: West to northwest 40/60 km / h.

SNOW CONDITIONS:
The snow depths are low for the end of February, especially in the southern slopes and at low altitudes.
Snow resists better in the north. Glaciers are in relatively good condition but their loss in thickness is clearly visible on the ground.
It is fitting the skis from 1100 m in sectors cold due north.
In southern slopes, ... Between 1600 and 1900 m depending on the slope steepness.

Quality of snow Thursday:
Unless 2000/2200 m in all slopes, except for a thin crust subjected surface in the morning, wet snow will be much of the day.

A more 2000/2200 m north side, is a small layer of snow recently powder in the order of 10 cm on the surface of the mantle. In southern side between 2000 and 2700 m, this small layer of snow over recent hours humidifies itself.

STABILITY OF SNOW COVER:
ALWAYS NATURAL HAZARDS OF LOCALIZED HUMIDIFICATION DUE TO THE MOUNTAINS ON AVERAGE SLABS AND SOME OF SURFACE AT ALTITUDE.

Indeed, in some fields not purged steep mountains on average, bottom slabs of wet snow/heavy triggering is still naturally at any time of night/day, especially on grassy soil or rock slabs. This risk will be located below 2000/2200 m in the steep slopes to the north, 2500 m in the steep slopes to the south. These wet snow, bottom slab avalanches, heavy, not very fast, can still generate a large deposit down, especially if they are channeled in a corridor (... filing with large blocks very hard). In addition, small cast surface, mobilizing only small layer of snow deposited over 1800/2000 m, will trigger spontaneously in steep in the sun, including sometimes in high mountain slopes in the mixed (snow / rock ).

Above 2000/2500 m depending on the orientation, the snowpack will remain quite stable although some scattered patches remain superficial, especially in the cold slopes (small hard slabs, or friable powder depending on location).

TREND LATER RISK:
On Friday and Saturday, stationary risk (moderate rainfall with a maximum of snowfall to 1600 m).

Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant.