PLEASE NOTE: this forecast is translated from the french using computer translation - some of the language used may be odd or misleading.
At this moment it is the nearest thing there is to an english avalanche forecast for the Chamonix area, and is provided by the excellent Pistehors.
Checking the original french forecast is recommended.
valid outside of marked and open ski runs
FOR WEDNESDAY JANUARY 3, 2007
(written on Tuesday January 2)
ESTIMATION OF THE AVALANCHE RISK TO WEDNESDAY EVENING:
All mountain ranges of Haute-Savoie:
higher than 2000/2200 m: HIGH RISK
low than 2000/2200 m: MODERATE RISK
WEATHER OUTLOOK TO WEDNESDAY EVENING:
Still some showers of snow in the night of Tuesday to Wednesday, then return to a dry weather for the day of Wednesday. Appearance of beautiful breaks.
Isotherm 0 DG: 1000 m the morning then 2200 m the afternoon.
Isotherm -10 DG: 2500 m then 3500 meters
Wind to 2000 m: north 20/30 km/h.
Wind to 4000 m: north 90 km/h.
snow cover improves even if there remains still deficient at low altitude.
Thicknesses of total snow this Wednesday morning:
To 1000 m: 15 to 30 cm.
To 1500 m: 30 to 40 cm.
To 2000 m: 60 cm with 1,20 meters These values are averages, there are also snow-drifts by places and of the zones stripped bare by the wind, in particular close to the peaks. The practice of the ski touring or rackets is comfortable starting from 1200 m on average, but attention up to 1800 m the stones are not far…
Quality of snow this Wednesday: one skis in general on 20 to 40 cm of powder. It is weighed down a little in the southern slopes of mid-mountain the afternoon. The winds of north in west strongly worked snow, of the snow-drifts appeared and it surface is very often hard pack close to the peaks.
STABILITY OF THE SNOW COVER: risk fragile slabs
Higher than 2000 to 2200 m, the snow cover is piègeux. One meets important irregularities from one slope to another, even within the same slope. The zones the least directly exposed to the winds preserved not badly depth hoar (snow with caster sugar texture “”). New snow adheres to it badly and the passage of only one skier or hiker can be enough to start an avalanche carrying all the layer of recent snow, even in the beautiful medium of a slope. These avalanches can leave in the form of soft slabs, very difficult to detect because made up of powder snow… a great prudence is thus recommended in out-track. In addition, below the peaks and close to the changes of incline, some windslab were formed, especially in north-eastern slopes in south-east. As each first day of good weather after a fall of snow, a great prudence is essential in out-track.
Low than 2000 to 2200 m, the rain made disappear the depth hoar and the conditions are thus announced piégeuses. Not very bulky slabs can be started by the passage of a skier, but they are definitely rarer and mainly localised close to the irregularities of northern ground in slopes south-east.
As for the spontaneous starting risk of avalanche, one can expect some rare cast, more or less bulky according to altitude, and mainly the afternoon on the steep slopes directed in south-west.
TENDENCY FOR THURSDAY:
Risk in light fall.
Weather-France updates this bulletin each day towards 16h or earlier if the nivometeorologic conditions require it.