February 2006

Weather > Snow Avalanche Conditions > February 2006

27th February 2006: 12:00 After a dull Friday that brought little fresh snow with it conditions were pretty much perfect at altitude above 1500m. The good weather also brought its share of avalanche incidents at les Arcs and Gourette in the Pyrenees. There was an avalanche on a north facing slope in the Haute-Maurienne and some cliff falls and a couple of dramatic rescues. A reminder to prospect your routes before setting out and to take care on the exposed, icy slopes that warmer weather brings.

There was good powder to be found on north sector slopes (but watch out for those slabs sitting on weak layers) and superbe spring snow on south facing slopes from mid-morning where the sun is out. We skied a "secret" route yesterday in the Chartreuse. Powder snow from 1700 meters right down to 950 although the valley is known as something of a deep freeze.

Conditions are looking fairly stable in the Haute-Savoie although there is a lack of snow at altitude and glacial routes should be treated with care. The main dangers are steep, convex slopes. The avy bulletin warns about old tracks which may form weak points in the snow pack. The situation is more worrying in the Savoie where the risk is High in the Haute-Maurienne and Considerable over much of the rest of the area. These kind of conditions call for excellent route finding skills off-piste. Test pits show the snow pack to be composed of a numer of layers interspersed with rain and freeze-thaw crusts. These can form sliding surfaces. Particular care should be taken close to the Italian border. The risk is also considerable in the Oisans (les Deux Alpes/la Grave etc.) where a strong east wind has formed new slabs on a weak base. The risk continues to be High or Considerable over the Southern Alps, scene of 7 of last week's avalanche deaths. The risk in these areas will persist at altitude for some time, pricipally from wind and soft slabs sitting on a very weak base.

24th February 2006: 21:00 The weather has taken a turn for the worse without really promising the snowfall we would like to see at the end of February. Thursday had a typical inversion layer and only skiers climbing above 2,000 m saw the sun. Today we climbed to a little Chartreuse peak called the Grand Som. No snow below 1050 meters and if you are heading on to south facing slopes don't expect to find skiable snow below 1500 meters. Slopes below 2000 meters seem pretty stable in the Northern Alps although you can kick of some sluffs of fresh snow above 1700m. We have also noticed some surface hoar forming around 1800m on all our outings this week, this confirms the return to cold weather but could be a potential weak layer for the future.

The principal danger remains in the Southern Alps. The body of another ski tourer was found today, 7 deaths in the last 5 days and a number of serious injuries. The avalanche risk is high over much of the area and looks set to persist. Further snow is expected over the next 24 hours.

22nd February 2006: 00:30 We were ski touring on a fairly low angled route in the Belledonne mountains yesterday. There is about 20cm of powder on a fairly well consolidated base above 1450 meters. We noticed a lot of cornices formed by the violent southerly winds over the weekend and some areas were slabby underfoot. The slope we climbed (north-east facing) had some thick crust in places with unconsolidated snow lower down. The powder on north-west slope that we skied seemed quite well bonded to the older snow which itself was fairly solid. Be careful skiing over any slabs formed on unconsolidated snow. Just a reminder that there have been six avalanche deaths over the last couple of days in the French Alps (see main news pages) and a number of very serious injuries across the Northern and Southern Alps including a piste patroller at Auron in the Maritime Alps.

19th February 2006: 19:30 The avalanche activity cut the Col de Montets between Chamonix and Switzerland on Friday and the Col du Lauteret between la Grave and Serre Chevalier is closed due to snowfall and strong winds.

In the Northern Alps Saturday was reasonably sunny with a refreeze down to 1000 meters. This stabilized the snowpack at mid-altitudes and the avalanche risk has descreased slightly. Sunday morning was fine but with a strong wind from the south. This gave way to snowfall above 1500 meters.

The best conditions are in the Savoie but this is also where the avalanche danger is greatest with many new slabs formed on various slope aspects under the action of the wind from the west and south and locally from the east and north-east. Even a small slab may trigger a larger avalanche. The risk is highest above 1800 meters altitude. There is also the risk of getting caught in a slide on a slope that has not yet purged.

The weather front that moved up from the south had already moved across the Southern Alps giving 20cm of fresh snow coupled with winds up to 150km/h. This has formed new accumulations and slabs the the risk of avalanche is high. There were some substantial natural avalanches on Sunday.

Conditions on the island of Corsica remain excellent despite the recent warm weather and rain. Around 15 - 30cm of fresh snow is expected tonight accompanied by a strong south-west wind. The snow is very icy and this will form a sliding surface for any new slabs, particuarly on north to north-east slopes. Natural avalanches are also to be expected.

The avalanche risk is also high in the Hautes-Pyrenees in particular above 2000m. The new snow is lying on a breakable ice crust and natural avalanches are likely on steep slopes with a high risk of slab avalanches on north to east slopes particuarly close to the frontier with Spain.

15th February 2006: 13:00 The PisteHors range gauge has recorded 43mm of rain between 14h30 yesterday and 11h00 this morning. That is the equivalent of 45cm of snow fall. However with the zero isotherm currently around 1800m you will have to climb pretty high to find it. The front was most active in the pre-Alps where it brought around 10cm of very wet and heavy snow at 1600 meters accompanied by moderate winds from the South-East veering South. Higher up in the Belledonne 40cm of snow fell at 2200 meters which should improve conditions. The picture was even better further north where temperatures are colder. 30cm fell in the Beaufortin area at 1700 meters and 50cm on the Bellecote above la Plagne at 3000 m.

The snow tended to die out towards the border with Italy and further south but it was accompanied by some very strong winds. In the Ecrins 40cm fell at 2900 but at la Grave and the Thabor there were winds of 100km/h plus with less than 10cm of fresh.

In the AiguillesRouge close to Mont-Blanc there was 35cm of fresh snow at 2500 meters but again with some very strong winds gusting to 80km/h.

The sun has now come out and the new snow rapidly purge from steep sunny slopes. Be very careful about the heavy new snow between 1600 and 2200 meters. This is sitting on an unstable base on north facing slopes and could cause wet snow slides on all aspects. Higher up new slabs will have formed on north sector slopes. In some places old hard slabs could be overloaded or form a sliding surface and there is still a layer of snow with little cohesion on shaded slopes. Caution!

15th February 2006: 12:00 After almost a month of stable weather in the Northern Alps things are set to change over the next 24 hours with a front moving in from the West. As usual this should give most snow in the pre-Alps: Aravis, Bauges, Chartreuse, Belledonne, Vercors and Devoluy. There will be snow from 1400 meters tonight but the SW wind will keep the temperatures mild. The snow level should rise to 1900-2000m over the course of Thurday with total snowfall about 50cm at altitude; however this will be accompanied by a strong Westerly wind so accumulations will be much deeper on north to south-east slopes. It is in this north to east sector where there are some remedial slabs and a lot of snow with little cohesion. In many places this is sitting on a relatively stable base but this will form a weak layer in the snow pack and the additional load will cause problems where the existing layers are poorly bonded. Expect the avalanche risk to rise to High above 2000-2200m before the weekend. The weather will cool Friday and this should stabilize the snow at lower altitudes.

12th February 2006: 09:00 The spring weather has continued over the weekend with excellent spring conditions on south facing slopes although the lack of recent snow means that skiable snow is only found at around 1500 meters except on sheltered paths. On shaded slopes snow extends down to 1000 meters. The overnight refreeze is good but watch out for wet snow slides in the afternoon. There is still some powder on all aspects above 2300 meters in the Northern Alps. The cold overnight temperatures continue to destructure snow on north facing slopes where there is a good layer of crystals with little cohesion but often on a solid base. Snow cover was thin at altitude with some routes unskiable due to the presence of rocks. Touring on Friday we found some thick slabs (around 30cm) on a number of aspects towards ridgelines so some care in route planning and group spacing is still required locally.

9th February 2006: 13:00 Last night's weather front brough just a few centimeters of snow to the northern alps, nothing to improve conditions that are suffering due to a prolonged sunny spell coupled with strong winds. We were touring in the Matheysin massive yesterday south-west of Grenoble. Continuous snow on western slopes begins around 1400 meters except for sheltered pockets and any areas exposed to the strong southerly winds of a couple of weeks ago was stripped bare of snow. It looked more like mid-March. As a consequence the avalanche risk is 2 (moderate) over all of the Northern Alps and there is certainly little risk in the morning where there has been a good overnight refreeze.

Snow conditions are slightly better in the Southern Alps, Massif Central and good to excellent in Corsica and the Pyrenees. It is noticable that the snow from the 26th of January pretty much stops on the northern edge of the Vercors. This snow is still causing some problems with slabs on north-west to east facing slopes. These are sitting on an unstable base of either facetted snow or depth hoar formed during the very cold weather early in January. Don't forget that the five recent avalanche deaths were in the Southern Alps and we had reports of skiers triggering avalanches off-piste in Auron and Valberg. As a consequence the avalanche risk is 3 (considerable). Tomorrow (Friday) promises to be a very sunny day in the south which could cause some instability on south-face slopes during the course of the day.

5th February 2006: 23:00 There has been a very strong inversion layer over our valley the last few days. The cloudbase was quite high today. At around 1500 meters it was very dense but the sun was out just a little higher up. Temperatures are colder which means the snow is refreezing better overnight and only just transforming during the day. A big change from Friday. There was a bit of fresh snow in the cloud - but only a couple of cm. The north to north-east wind is expected to strengthen during Monday which will move some snow around and form some new slabs.

3rd February 2006: 20:00 We headed for the Vercors today which has some of the conditions in the Alps at the moment. A little couloir called the Peyrouse above the ski resort of Gresse en Vercors. Although the weather has got a bit colder, zero isotherm around 2000 meters the overnight refreeze was not very deep below 1600 meters. We skied down around 11h00 and even this was a bit late on east facing slopes oriented around 25-35 degrees. As long as the good weather continues avoid these slopes off-piste from late in the morning and south sector slopes in the afternoon. The temperatures will drop over the weekend.

Last week's violent "foehn" southerly wind dumped some Saharan sand on the mountains and you may have noticed some dirty looking snow. There is some debate about whether this forms a sliding surface for slabs. In some "rutschblock" tests we did in 2004 this seemed to be the case. The strong wind has removed a lot of snow from windward slopes at altitude, the snow on north facing slopes has been compacted and any slabs are fairly thick - group spacing is important. However the colder weather will start to destructure the snow crystals in these slabs setting up the next avalanche cycle. Powder is in short supply. According to the Meteo France bulletin the greatest risk of snow slabs is between 1800 and 2200 meters particuarly on steep and convex slopes.

1st February 2006: 23:00 Some news from the Vallée Blanche guides. The route is skiable to Chamonix, watch out for branches on the Mottets path. Crevasses are open and should be treated with care in some places. There has been some serac fall before the Requin. The snow has been packed by the strong southerly wind in places and is hard to ski. It is reccomended to stick to the classic route in current conditions. This has been well skied. There is bare ice visible on the mer du Glace.

The warm weather has improved the stability of the snowpack, especially at lower altitudes but watch out for increasing avalanche activity increasing during the course of the day espeically but not only on south sector slopes. The zero isotherm in the Northern Alps is between 2500-2800 meters.

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