Chamonix weather forecast snow report from Henry's Avalanche Talk

Snowpack Report

What an amazing couple of weeks. Rarely have I seen so much snow and such a stable snowpack at the same time.

The snows that are coming now (end of week of March 24) are supposed to be fairly light, in terms of accumulations and in consistency, throughout the Northern French Alps and surrounding areas.

Current Stability

There have been quite a few accidental slab releases over the last few days (Météo France has reported several each day) most without consequence probably because the slabs have not been all that big and/or the people were able to ride out or weren’t taken too far. I have seen and heard of a few slabs triggered at distances of 10 metres or so on slopes facing North East to East – which makes sense since the winds have been mostly coming out of the West & North West and this will continue through the weekend. The winds aren’t supposed to be as strong for this weekend and that is a relief!

Tip of the week:

Watch out for slab instability (& releases) as a direct result of very recent wind loading on slopes and in general areas that were/are protected from wind in recent storms (these are very often East’ish’ slopes, but not always!!). Some of the very recent slab releases have had fractures at the top (or crown walls) of up to 70 cm. So, despite the exceptional stability of all this new snow, I’m still being very careful as I enter into steep areas of nice smooth fresh white snow.

‘Ride Hard Ride Safe’!

Henry

Slabs Triggered from a distance

there were quite a few slabs triggered from a 10 metre distance observed by colleagues and me today. Also, natural, artificial & other accidental in Savoie & Haute Savoie mainly small for the moment. This slope under the Mt Blanc chair in Val d'Isère is facing North East. The wind has been mostly coming out of the North West (although is supposed to change to South briefly tomorrow then back to North West through West for Thursday on through the weekend). This slab, a direct result of very recent wind loading, exemplifies what is in store for the next few days (and so does the distance triggering). Only I think the instability will grow with the continued wind loading and new snow accumulations. The avalanche activity has been relatively calm over the last 10 days or so, but I think the instability could pick up with all this new snow and wind over the next few days. The slab in this photo and the way it was triggered is telling us something.

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.

N74250311
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OUT OF OPEN AND MARKED RUNS)
PREPARED ON TUESDAY 25 MARCH
FOR WEDNESDAY 26 MARCH

ESTIMATE OF RISK UNTIL WEDNESDAY EVENING:
All massive Haute-Savoie:
Higher than 2000 m: marked risk (level 3)
Lower than 2000 mm limited risk (level 2)

WEATHER OVERVIEW UNTIL WEDNESDAY EVENING:
Cloudy night from Tuesday to Wednesday and Wednesday early morning and then pretty nice periods of sunshine in a sweet atmosphere.
Temperatures planned to 1500 m 2 to -8 (shadow).

Isothermal 0 1500 m.
Wind around 2000 m: low.
Wind around 4000 m: Northwest 100 km / h decreasing 50 mph and turning west Wednesday afternoon.

SNOW CONDITIONS:
They become very good for a late March, circa 1000 m there are 20 to 55 cm, circa 1500 m to 80 cm of snow total 1m35. It is white until at very low altitude.
This is an opportunity to make departures skis or snowshoes to toe when 1000/1200 m, paying attention to the rocks and other obstacles barely hidden.

Quality of snow for Wednesday: often still of good powder, but that will grow fast enough under the influence of the sun. Around the mid-mountain peaks, snow is blown and wavy, or a thin layer of powdery snow covering very hard, even icy. Large mountain slopes exposed to the northwest are also in compacted snow.

STABILITY OF SNOW COVER:
Some localized accumulations fragile and departures heating.
For two weeks, the episodes have succeeded disturbed, the most important being that of Friday, March 21 accompanied by stormy winds from the west to southwest. This Tuesday morning, the snow was 20/30 cm since 1000 m (lower layers in the MT-Blanc), the wind was blowing northwest storm last night.
The snowpack is still moderately to weakly bonded, we should avoid steep slopes near the passes and peaks and slopes failures as the risk remains important to break a slab to a depth sometimes close to 1m. Wednesday under the influence of the sun (caution north), those risks will gradually decline or even disappear in mid mountain. At the opposite, in the corridors and walls, the heat will result in purges (in the morning between east and south), which may give some fairly large avalanches (as in Aravis). Although thus take into account the risks for a hike even on a plateau but with steep slopes nearby. Beware also cornices, some are already fractured into 2000/2500 m.

TREND LATER RISK:
A new layer of snow is expected overnight Wednesday to Thursday (20 cm to 2000 m).
The risks are expected to remain stationary.

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

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.

N74240311
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OFF OF OPEN AND MARKED RUNS)
PREPARED ON MONDAY 24 MARCH
FOR TUESDAY 25 MARCH
ESTIMATE OF RISK UNTIL TUESDAY EVENING:
All massive Haute-Savoie:
Below 1800 m: marked risk (level 3)
Above 1800 m: marked risk (level 3) operating locally in high risk (level 4).

WEATHER OVERVIEW UNTIL TUESDAY EVENING:
Snow windy during the night. Tuesday, still snowfall gradually weakening in the morning, sunny in the afternoon. Quantities of fresh snow expected since Monday afternoon: 20/25 cm at 1000 m, locally 30/40 cm above 2000 m.
Isothermal 0 DG: 800 m.
Wind at 2000 m: West 50 and 30 km/h.
Wind at 4000 m: Northwest 110 km/h.

SNOW CONDITIONS:
With winter moved over the past few days, snow has improved markedly. At 1000 m on Monday, measuring between 20 and 40 cm, and 1500 m in the north a little more than 1 m of snow.
Quality of snow for Tuesday: there will be a good layer of snow, light and powdery, and worked blown by the wind in exposed areas. At low altitude, the layer of snow based on a sub-layer crust.  With warm in the afternoon, the snow will increase to below 1800 m and humidify itself in a little sun at low altitude.

STABILITY OF SNOW COVER:
Fragile slabs and few natural avalanches quite large.

The heavy snow last Friday were packed and stabilized as a whole. Instability comes essentially from the fresh snow surface and blown the night based on a cold and snow lightly.

The risk of an avalanche of hard or brittle slabs will be marked Tuesday, particularly in areas where the accumulation of snow blown by the night will be filed, thus shifted away from the peaks or the big breaks slopes but also possible but a more localized in the morning. Tuesday afternoon, with light, the risk of brittle slab could rise another notch and the same well below peaks. The mere passage of a skier in this case could trigger the slab. The slabs themselves may not be thick but the resulting avalanche that could take in a large volume slope towards the thickness of snow and cold anywhere.

As to the risk of avalanches, it will gradually increase with the snowfall by Tuesday noon in a few steep slopes before faltering in the afternoon. Again, these avalanches dusters could be locally heavy enough for the thickness of snow anywhere especially in the case of departure-2000 m.

TREND LATER RISK: Risk down slightly for Wednesday
Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant nivométéorologiques.

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.

N74220311
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OFF MARKED AND OPEN RUNS)
PREPARED ON SATURDAY MARCH 22
FOR SUNDAY MARCH 23
ESTIMATE OF RISK UNTIL SUNDAY EVENING:
Massif du Mont Blanc: marked risk (level 3), Approaching a high risk (level 4) during the day.
Massive Aravis and Chablais:
A more 1800/2000 m: marked risk (level 3), close to a high risk (level 4) during the day.
Unless 1800/2000 m: limited risk (level 2), close to a marked risk (level 3) during the day.

WEATHER OVERVIEW UNTIL SUNDAY EVENING:
Even some low snowfall this Saturday afternoon taking a character giboulées (5 / 10 cm of snow) and then lull during night and part of Sunday morning under a sky divided between some light passages cloudy . Return to strength of clouds and snow giboulées Sunday mid-day and afternoon (10/20 inches of snow and cold light).
Temperatures 1500 m: -4 to -7 degrees.
Isothermal 0 DG: plain in the morning, then to 900 m Sunday afternoon.
Isothermal -10 DG: 2000 to 2200 m.
Wind at 2000 m: Southwest tonight then north Sunday, 20/30 km / h.
Wind at 4000 m: north-west then north, 20/30 km / h.

SNOW CONDITIONS:
They are excellent in view of the beautiful and abundant snowfall fresh recent 36 hours. Indeed, the thickness of the snowpack is now higher than normal for this time of year, including in the valley bottoms to 1000 m.
At 1000 m, measuring 30/50 cm of snow on the ground according to the valleys and much more in altitude ...
Quality of snow this Sunday: powder on a good thickness. It increases slightly below 1600 m, particularly in the eastern and southern slopes and on replats, but remains cold and light a little higher on average mountain. Nearly peaks and high altitude, there are important irregularities thick snow because of stormy winds on Friday. Expect big snowdrifts everywhere and even snow often worked closely compacted ridges and in areas recently windy, covered with a small layer of snow on little windy.

STABILITY OF SNOW COVER:
Fragile slabs and large avalanches always possible in large steep.
The accumulations of snow reached 40 to 60 cm at 2000 m, 70/80 cm locally in the Mont Blanc massif. Of the ridges and exposed areas, the winds of Southwest blew between 70 and 100 km / h Friday during the snowfall.
Risk of naturallly starting avalanches: the very thick of snow will gradually cup to less than 1600 m, taking a bit of cohesion, but above it is not yet stabilized Sunday. We must expect some purges in steep areas, particularly in east to south with the possible thinning of the morning. A start between 2000 and 2500 m could form a big avalanche of powder with aerosol and spread fairly low altitude.
The risk of an avalanche under the weight of a skier (s): friable many slabs whose surface is powdery snow, were formed recently. Suddenly, in a steep, the transition from one off-piste skier will sometimes be enough to trigger an avalanche mobilizing these accumulations of snow unstable and fragile. The risk is highest in the Mont Blanc massif, and above 1800 m in the Aravis / Chablais. Much distrust becomes the slopes in Northwest, North and East, especially between 2000 and 2600 metres where the snowpack already showed some weaknesses before the snowfall. In these circumstances, we can choose to focus on hiking routes little stiff, avoiding areas and large convex slopes above sea level, or even to walk down.
TREND LATER RISK:
Risk stationary or slightly decreasing.
Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant nivométéorologiques.

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.

N74210311
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OFF MARKED AND OPEN RUNS)
PREPARED ON FRIDAY 21 MARCH
FOR SATURDAY MARCH 22

ESTIMATE OF RISK UNTIL SATURDAY EVENING:

Massif du Mont Blanc: high risk (level 4)
Massive Aravis and Chablais:
Higher than 1800 m: high risk (level 4)
Lower than 1800 m: marked risk (level 3)

WEATHER OVERVIEW UNTIL SATURDAY EVENING:
The snowfall continues into the night of Friday to Saturday, about 10/15 cm. Saturday, a little clearing is possible in the morning, but still a lot of clouds. Snow in the afternoon, an additional 10 cm at 2000 m. Temperatures 1500 m: -2 to -4 DG.
Isothermal 0 DG: 900 m.
Wind at 2000 m: Southwest 20/30 km/h.
Wind at 4000 m: West 40 km/h.

SNOW CONDITIONS:
Beautiful increase in progress. This snow is based directly on the ground below 1200 m in the north, 1500 m in the South.
Quality of snow on Saturday: powder with a good thickness. It increases slightly below 1500 m but remained cold and light in the middle mountain slopes sheltered from the wind. Major irregularities in altitude because of stormy winds this Friday: large snowdrifts across snow and even worked closely compact peaks and windy areas.

STABILITY OF SNOW COVER: fragile slabs and large avalanches possible

The accumulations of snow reached 30 to 50 cm at 2000 m, 70 cm locally in the Mont Blanc. The wind of Southwest blew between 70 and 100 km / h Friday during the snowfall.

Likelihood of spontaneous departure avalanche: the very thick of fresh snow had not had time to stabilize. It is expected purges in the steep, especially with east to south under the light of the morning. A start between 2000 and 2500 m could form a big avalanche of powder with aerosol and spread fairly low.

The risk of an avalanche: friable many slabs were formed, sometimes covered in the powdery fell with less wind during the night. The passage of a single off-piste skier can be enough to trigger an avalanche in these accumulations unstable and fragile. The risk is highest in the Mont Blanc and Aravis / Chablais above 1800 meters. Much suspicion is the slopes in Northwest, North and East, especially between 2000 and 2600 meters where the snowpack already showed some weaknesses before the snowfall. In these circumstances, we can choose to focus on hiking routes little stiff, avoiding areas and large convex slopes above sea level.

TREND FOR SUNDAY: Stationary risk globally, fewer departures spontaneous but fragile slabs.
Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant nivométéorologiques.

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.

N74200311
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.

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.

N74190311
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OFF OF OPEN AND MARKED RUNS)
PREPARED ON WEDNESDAY 19 MARCH
FOR THURSDAY 20 MARCH
ESTIMATE OF RISK UNTIL THURSDAY EVENING:

All massive Haute-Savoie: limited risk (level 2).

WEATHER OVERVIEW UNTIL THURSDAY EVENING:
Wednesday night cloudy with a few snow showers. Thursday: quite sunny with a sun increasingly warped.

Isothermal 0 800 1000 m.
Wind at 2000 m: North-east, 40 decreasing in the afternoon.
Wind at 4000 m: North 70 km/h.

SNOW CONDITIONS:
Snow is correct for a mid-March over 1700m, weak at low altitude. It is fitting the skis to 1300 m in northern cold in the valleys. In South direction, it's best to climb to 1800 m in the absence of sub-layer to a lower altitude.

Quality of snow Thursday: Lowest approximately 1800 m, snow will be hard crust or with a thin layer of powder on the surface, then it will become progressively wetter in the sunny slopes. At higher elevations, snow will remain colder, either hard or crusty on southern slope until about 2500 m, a powdery more or less packed, or a hard snow by the wind.

STABILITY OF SNOW COVER:
Few slabs, but can be voluminous.

The snowfall from last weekend is now rather well consolidated. However, a few slabs still persist in some places. These slabs tend to be thick and not very easy to trigger.

The main risk will therefore trigger a slab avalanche with the passage of a person and especially with the passage of a group of people, mainly in northern slopes above 2000 meters. These slabs will be sparse but could be quite bulky.

As for spontaneous avalanches, they will be rare. This mostly isolated departures of wet snow avalanches in steep mountain slopes average, especially on sunny slopes.

TREND LATER RISK:
Friday, the risk will increase strongly.
Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant nivométéorologiques.

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.

N74180311
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OFF OF OPEN AND MARKED RUNS)
PREPARED ON TUESDAY 18 MARCH
FOR WEDNESDAY 19 MARCH

ESTIMATE OF RISK UNTIL WEDNESDAY EVENING:
All massive Haute-Savoie:
Higher than 2000/2200 m: marked risk (level 3)
Lower than 2000/2200 m: limited risk (level 2)

WEATHER OVERVIEW UNTIL WEDNESDAY EVENING:
Sunny in the morning, in charge of cumulus by passages in the afternoon.
Temperatures: -9 then -5 DG to 2000 m, -18 to the Aiguille du Midi.
Isothermal 0 1200 m.
Wind at 2000 m: North 20 km / h.
Wind at 4000 m: Northwest 30/50 km / h.

SNOW CONDITIONS:
Correct above 1500 m, low at low altitude. It is fitting the skis to 1300 m in northern cold in the valleys. In South direction, it's best to climb to 1800 m in the absence of sub-layer to a lower altitude.
Quality of snow on Wednesday:
Full north, the snow remains fairly mild cold and above 2000 m. The sunny slopes, and those who have seen the fog had already risen up to 2400 m. In the high mountains, the powdery snow keep better but it was still worked in areas prone to wind West. Glaciers are better plugged it remains fragile bridges in the lower elevations.

STABILITY OF SNOW COVER: Slabs especially at altitude

Between Sunday and Monday, 20 to 30 cm of snow fell at 1500 m, 40 to 60 cm above 2500 m, accompanied by westerly winds.

More low as 2000/2200 m, the recent snow is in the process of settling, or even already suppressed in the hills taking a little sun. Some small flows occur in the snow surface orientation South East to South-West at the discretion of the sunshine. The slabs are scarce and small, confined to locations cold and shaded. The risk of triggering a slab is mainly confined to areas behind the usual ridges or under dished.

More than 2000/2200 m high, it remains brittle slabs more and thicker. Some have already served only on Tuesday, particularly in Northwest to 2400 m with breaks neighboring 30/50 cm. It should therefore exercise caution, especially in guidance Northwest, North and East where the winds brought accumulations fragile likely to break the passage of a single hiker. Distrust in steep and sub slope failures, especially in areas with low skiées since the snowfall last Wednesday.

TREND FOR THURSDAY: continuation of the settlement, risk down slightly.
Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant nivométéorologiques.

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.

N74180311
SNOW AND AVALANCHE BULLETIN FOR HAUTE SAVOIE
(VALID OFF OF OPEN AND MARKED RUNS)
PREPARED ON TUESDAY 18 MARCH
FOR WEDNESDAY 19 MARCH

ESTIMATE OF RISK UNTIL WEDNESDAY EVENING:
All massive Haute-Savoie:
Higher than 2000/2200 m: marked risk (level 3)
Lower than 2000/2200 m: limited risk (level 2)

WEATHER OVERVIEW UNTIL WEDNESDAY EVENING:
Sunny in the morning, in charge of cumulus by passages in the afternoon.
Temperatures: -9 then -5 DG to 2000 m, -18 to the Aiguille du Midi.
Isothermal 0 1200 m.
Wind at 2000 m: North 20 km / h.
Wind at 4000 m: Northwest 30/50 km / h.

SNOW CONDITIONS:
Correct above 1500 m, low at low altitude. It is fitting the skis to 1300 m in northern cold in the valleys. In South direction, it's best to climb to 1800 m in the absence of sub-layer to a lower altitude.
Quality of snow on Wednesday:
Full north, the snow remains fairly mild cold and above 2000 m. The sunny slopes, and those who have seen the fog had already risen up to 2400 m. In the high mountains, the powdery snow keep better but it was still worked in areas prone to wind West. Glaciers are better plugged it remains fragile bridges in the lower elevations.

STABILITY OF SNOW COVER: Slabs especially at altitude

Between Sunday and Monday, 20 to 30 cm of snow fell at 1500 m, 40 to 60 cm above 2500 m, accompanied by westerly winds.

More low as 2000/2200 m, the recent snow is in the process of settling, or even already suppressed in the hills taking a little sun. Some small flows occur in the snow surface orientation South East to South-West at the discretion of the sunshine. The slabs are scarce and small, confined to locations cold and shaded. The risk of triggering a slab is mainly confined to areas behind the usual ridges or under dished.

More than 2000/2200 m high, it remains brittle slabs more and thicker. Some have already served only on Tuesday, particularly in Northwest to 2400 m with breaks neighboring 30/50 cm. It should therefore exercise caution, especially in guidance Northwest, North and East where the winds brought accumulations fragile likely to break the passage of a single hiker. Distrust in steep and sub slope failures, especially in areas with low skiées since the snowfall last Wednesday.

TREND FOR THURSDAY: continuation of the settlement, risk down slightly.
Meteo-France updates this newsletter everyday at 16h or sooner if conditions warrant nivométéorologiques.