Since the avalanche incidents last week in the Northern Alps and Pyrenees the weather has remained very cold with temperatures around -10C at 1700 meters altitude during the day. This has slowed down the natural stabilization of the snow pack. We were ski touring in the Chartreuse on Sunday which has excellent snow conditions. We measured around 2 meters of snow at 1750 meters. However we also noticed a thin layer of surface hoar crystals which would have been buried by Tuesday’s snowfall. This is a possible weak layer especially where there are accumulations of snow.
Ski Touring in the Chartreuse
Tuesday saw fresh snowfall, around 25cm in the Mont-Blanc massif, 15cm in the pre-Alps to the west trailing out to 5cm in the east of the Maurienne and Oisans. This was accompanied by cold weather and strong North to North-East winds. Some fresh slabs will have formed on sheltered slopes and there is the persistence of some larger old slabs from the previous snow fall. These old slabs are often hard to detect due to the fresh snow. Even a small slab could trigger weaker layers below. The risk is higher above 1800 meters altitude on shady aspects (North to North-East). Some of the older slabs require a significant load to be triggered so groups should space out in zones at risk.
After 10 days of artic conditions the weather is warming up today with the zero isotherm around 2000 meters at the warmest part of the day. This could provoke some purges on warmer slopes and will humidify the snow pack on Southern Aspects. There is a light North-East wind and conditions should remain calm and sunny until Sunday.
Snow cover is good, especially in the pre-Alps (Chartreuse and Belledonne). It is possible to ski to around 800-1000 meters. Powder can be found on East, North and West aspects with a breakable crust on South-East to South-West facing slopes. However at altitude the snow cover is erratic and the surface hard due to the strong winds.
Southern]http://pistehors.com/backcountry/wiki/Ski-Areas/Southern-Alps]Southern Alps[/url]
The recent snowfall has had trouble penetrating to the Southern Alps and conditions are well below average with skiing to around 1300 to 2400 meters depending on the slope aspect and latitude. Reports from resort say that there are lots of rocks off-piste.
After a cold but dry spell the weather is quite warm with the zero isotherm above 2000 meters and a breeze from the North-East. The dangers remain where there has been snowfall or snow has been moved around by strong winds. This is principally at altitude and close to North of the region in couloirs and bowls where there are also some unstable layers in the snow pack.
The last week saw some 20 to 30cm of fresh snow accompanied by strong North to North-East winds. This even left the sea-fronts looking wintry. This was followed by warmer, sunny weather. Today is slightly colder weather for Corsica on Friday with the chance of a dusting of snow coupled with a breeze from the North-West to North-East. Snow cover and quality is good but very variable. In some wind loaded South-West couloirs there is up to a meter of snow at 1600 meters altitude. These accumulations should also ring alarm bells and backcountry travelers should be aware of the danger of soft-slab avalanches on South facing and on other well shaded slopes. Some of these slabs will be hard to detect beneath fresh snow. With the cold weather the stability of the snow pack will not change much. North-East aspects have had a lot of snow stripped by strong winds. It is possible to ski down to 1000 meters in places.
Last weekend saw around 30cm of fresh snow in the Central Pyrénées accompanied by strong winds from the North-East, particularly in the Eastern part of the range. On Thursday there was a fatal avalanche at Barèges and a second avalanche in almost the same spot on Sunday injured a snowboarder. The cold weather has slowed down the stabilization of the snow pack.
The snow cover is excellent, it is possible to ski between 800 to 1000 meters in central areas to 1300 meters closer to the Mediterranean. The strong wind from the North-East has formed a number of slabs, even some distance away from ridgelines. These could be triggered by the passage of a single backcountry traveler. These are largely on sheltered South to West slopes although can be found on all aspects to the East of the mountains where the wind was much stronger.
The cold weather has lead to a very slow stabilization of the snow pack, particularly on East, North and West facing slopes. Today is sunny and slightly warmer with the zero isotherm at 1500 meters in the West, 1800 meters in the East with a light breeze from the South.
References
This information is a summary of current conditions and is provided for information only. It is based on direct observations and information from the following sources.
Météo France issues daily avalanche bulletins for the French Alps, Corsica and Andorra. You should ideally consult at least the previous 5 days bulletins prior to your trip in order to have an idea of recent conditions.
recorded in Camp2Camp and Bivouac have trip reports with observations of the snow conditions.
Weather information is complemented by the USAF Public Weather Charts
Henry’s Avalanche Talk publishes a daily translation of the Météo France bulletin for the Savoie area.