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.
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OFF OF OPEN AND MARKED RUNS)
PREPARED ON THURSDAY 20 MARCH
FOR FRIDAY 21 MARCH
NOTICE OF HIGH RISK OF AVALANCHES FOR HAUTE SAVOIE
ESTIMATE OF RISK UNTIL FRIDAY EVENING:
All massive Haute-Savoie:
More low as about 1700 m, limited risk (level 2) are evolving rapidly in marked risk (level 3)
More high as 1700 m, marked risk (level 3) evolves likely (level 4).
WEATHER OVERVIEW UNTIL FRIDAY EVENING:
Big bad, heavy snowfalls accompanied by a lot of wind. Quantities of fresh snow expected Friday night: 20/25 cm at 1000 1500 2000 m.
But with wind, snow will be irregular at altitude.
Isothermal 0 600 1200 m.
Wind at 2000 m: Southwest 70, then west 50 km/h.
Wind at 4000 m: West to northwest, 110 km/h.
SNOW CONDITIONS:
The snow goes well improve Friday with snowfall expected, especially at low altitudes. This snow is directly on the floor below 1200 m in the north, 1500 m in the south.
Quality of snow for Friday: The layer of fresh snow at any little thick early morning rise rapidly over the hours. The powdery snow will be housed in places but blown and shaped by the wind going up in altitude. In the afternoon, the snow surface will be heaviest below 1500 m, and even a bit wet below 1200 m.
STABILITY OF SNOW COVER: Avalanche risk becoming important
The snow conditions will deteriorate sharply Friday. Over the hours, unstable slab formations, or by wind and more localized in the areas of accumulations, or by the structure of the snowfall itself which will slab well fragile and brittle at the end morning. These brittle slabs will be present in many places, and well below peaks. Some of these slabs could be triggered naturally, a fortiori the passage of a single person's departure will encourage this type of avalanche. Given the quantities of snow anywhere, these avalanches could be quite big in the afternoon, especially in the amount aloft.
During the snowfall, it will be expected to drain in the steep slopes, in the form of an avalanche of powdery snow, especially in the afternoon with larger avalanches.
TREND LATER RISK:
Saturday and Sunday, the risk of avalanches will depend on the snow that will fall, it might be down slightly, but the risk of triggering an unstable slab will be important and a great Caution is advised.
Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant nivométéorologiques.
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