AvalancheClarity

Mont-Blanc

Danger level 2 Moderate
Bulletin date: Saturday, April 25, 2026 at 04:00 PM
Valid until:

Ski resorts in this massif: Chamonix (Brévent-Flégère), Chamonix (Grands Montets / Argentière), Chamonix (Le Tour-Balme), Vallorcine, Les Houches, Megève, Saint-Gervais-les-Bains, Saint-Nicolas-de-Véroce, Combloux, Les Contamines-Montjoie

This is an AI-generated translation and summary. It may contain errors. Always read the full official Météo-France avalanche bulletin before any mountain activity.

Source: Météo-France

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Avalanche risk assessment bulletin

(valid outside of marked and open slopes)

MASSIF: Mont-Blanc

written on Saturday, 25 April 2026 at 4 p.m.

Pour consulter la vigilance en cours, veuillez vous rendre sur le site https://vigilance.meteofrance.fr/fr

Risk assessment for Sunday, 26 April 2026

Spring conditions


            Risque détaillé
NESW

Risk indices: 5 very high - 4 high - 3 considerable - 2 moderate - 1 low -- In black: the most dangerous slopes

Low risk index evolving to moderate.

Naturally triggered avalanches: wet snow avalanche

Skier-triggered releases: small wet snow slides under skis

Stability of the snow cover until Sunday, 26 April evening

Typical avalanche situation:Wet snowWet snowPersistent weak layerPersistent weak layer

Naturally triggered avalanches: 
* rare wet snow avalanches, more numerous as warming and solar radiation increase. Below 3000 m on north aspects and 4200 m on south aspects. Size 1 to 2 (small to medium). In the 2300/3000 m range, on east, west and north aspects, small point-releases can trigger a larger slab in a cascade. Rare size 3 (large). Due to an old persistent weak layer currently becoming wet. 
* a few glide slabs on grassy areas or rock slabs, at any time of day or night. Below 2500 m. Size 2 (medium). 

Skier-triggered releases: 
* wet snow avalanches below 4200 m on south aspects and 3000 m on north aspects. Easy to trigger in the sun. Point-release under the skis. Size 1 to 2. Caused by warming and solar radiation. 

Snow quality

    Snow conditions: 
For the season, snow conditions are below average below 3000 m 
Skiing is possible above 2000 m on south aspects and 1600 m on north aspects. 

Snow quality this Sunday morning: 
* below 2000 m, firn snow with good overnight refreezing.
* below 3000 m on north aspects and 4000 m on south aspects, spring snow with good overnight refreezing. 
* above 3000 m on north aspects and 4000 m on south aspects, snow still cold with many places where ice is exposed. 
  

Weather overview for Sunday, 26 April

nightmorningafternoonevening
Sunny. Cumulus clouds over the terrain in the afternoon. Maximum 12°C at 2000 m.
Rain-Snow----
Iso 0°C3100 m3300 m3200 m3200 m
Wind 2000 m 5 km/h 10 km/h 5 km/h 10 km/h
Wind 4000 m 20 km/h 20 km/h 20 km/h 10 km/h

Off-piste snow depth

Sat. 25 April N S 220 cm 2500 m 110 cm 2000 m 0 cm 1500 m 140 cm 2500 m 40 cm 2000 m 0 cm 1500 m Continuous snow cover altitudes: North face : 1600 m South face : 1900 m

Precipitation at 1800 m

Cumulated quantities in 24 hours Fresh snow at 1800m Fresh snow Min Fresh snow Max Rain 5 10 Snow (cm) / Rain (mm) 0 0 0 Wed. 22 at 6h 0 0 0 Thu. 23 at 6h 0 0 0 Fri. 24 at 6h 0 0 0 Sat. 25 at 6h 0 0 0 Sun. 26 at 6h 0 0 0 Mon. 27 at 6h

Outlook for Monday, 27 April

Risk index moderate

Monday: dry weather and rare cumulus in the afternoon. 0°C isotherm around 3000 m. ⇒ continued wetting of the snow cover

Snow-weather conditions for the last 7 days

Last 7 days

Sun. 19/04Mon. 20/04Tue. 21/04Wed. 22/04Thu. 23/04Fri. 24/04Sat. 25/04
03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h
Weather
Wind
(km/h)
at 4000m
35354040506060505050506070604030304030201020202030404040
Wind
(km/h)
at 2000m
1015201515152015101520101010555101010551055101510
Iso 0°CRain-snow limit
Altitude (m)
3200
2400
1600
800
0
Sun. 19/04Mon. 20/04Tue. 21/04Wed. 22/04Thu. 23/04Fri. 24/04Sat. 25/04
Fresh
snow (6h)
0 cm
Avalanche
Risk
Snow cover North and South at  1500m···   2000m- - -   2500m
Total snow
depth (cm)
320
240
160
80
0
1010105150140140130130120110260250250240240230220
Sun. 19/04Mon. 20/04Tue. 21/04Wed. 22/04Thu. 23/04Fri. 24/04Sat. 25/04
Snow limit - North face   Snow limit - South face
Snow
limit (m)
2400
2100
1800
1500
1200
900
600
300
0
1600160015001500150015001600 1700180018001800180018001900
Sun. 19/04Mon. 20/04Tue. 21/04Wed. 22/04Thu. 23/04Fri. 24/04Sat. 25/04
Iso 0°C RSL Weather
at
1800m
Wind at
2000m
Wind at
4000m
Sun. 19/0403h2 800-
10
35
09h2 800-
15
35
15h2 7002 400
20
40
21h2 600-
15
40
Mon. 20/0403h2 700-
15
50
09h2 600-
15
60
15h2 600-
20
60
21h2 700-
15
50
Tue. 21/0403h2 700-
10
50
09h2 700-
15
50
15h2 600-
20
50
21h2 600-
10
60
Wed. 22/0403h2 600-
10
70
09h2 600-
10
60
15h2 700-
5
40
21h2 700-
5
30
Thu. 23/0403h2 700-
5
30
09h2 900-
10
40
15h3 000-
10
30
21h3 000-
10
20
Fri. 24/0403h3 000-
5
10
09h3 200-
5
20
15h3 200-
10
20
21h3 200-
5
20
Sat. 25/0403h2 900-
5
30
09h2 800-
10
40
15h2 900-
15
40
21h3 000-
10
40
Avalanche
risk
Snow limit Snow depth at
2000m
Fresh snow at
1800m
Sun. 19/04N : 1 600 m
S : 1 700 m
N : 150 cm
S : 80 cm
0 cm
Mon. 20/04N : 1 600 m
S : 1 800 m
N : 140 cm
S : 70 cm
0 cm
Tue. 21/04N : 1 500 m
S : 1 800 m
N : 140 cm
S : 70 cm
0 cm
Wed. 22/04N : 1 500 m
S : 1 800 m
N : 130 cm
S : 60 cm
0 cm
Thu. 23/04N : 1 500 m
S : 1 800 m
N : 130 cm
S : 60 cm
0 cm
Fri. 24/04N : 1 500 m
S : 1 800 m
N : 120 cm
S : 50 cm
0 cm
Sat. 25/04N : 1 600 m
S : 1 900 m
N : 110 cm
S : 40 cm

La documentation utile à la bonne lecture de ce BRA est disponible sur le guide avalanche 2025

Rédigé par Météo-France avec la contribution des observateurs du réseau nivo-météorologique. Partenariat : ANMSM (Maires de Stations de Montagne), DSF (Domaines Skiables de France), ADSP (Directeurs de Pistes et de la Sécurité des Stations de Sports d'Hiver) et autres acteurs de la montagne.

French Translation & Notes
Conditions printanières
Spring conditions
*Printanières* is the adjective for spring (*printemps*). In avalanche terms, this indicates a diurnal cycle of freezing and thawing.
Départs spontanés :
Natural releases:
*Départs spontanés* literally means "spontaneous starts," referring to natural avalanches that occur without human triggers.
rares avalanches de neige humide, plus nombreuses au fil du réchauffement et du rayonnement solaire.
rare wet snow avalanches, more numerous as warming and solar radiation increase.
*Neige humide* (wet snow) is the main hazard. *Au fil du* means "over the course of" or "as... progresses." *Rayonnement solaire* (solar radiation) is a primary driver of instability in spring.
En dessous de 3000 m en nord et 4200 m en sud.
Below 3000 m on north aspects and 4200 m on south aspects.
Note the significant difference in altitude between aspects; the sun's influence is much higher on southern slopes.
Taille 1 à 2 (petite à moyenne).
Size 1 to 2 (small to medium).
Standard European avalanche sizing (D1-D5).
Dans la tranche 2300/3000 m, dans les versants est, ouest et nord, de petits départs ponctuels peuvent déclencher, en cascade, une plaque de plus grande ampleur.
In the 2300/3000 m band, on east, west and north slopes, small point releases can trigger, in a cascade, a larger-scale slab.
*Tranche* refers to an elevation slice/band. *Ponctuels* refers to point-release avalanches (loose snow). *En cascade* describes a smaller slide triggering a larger one.
Rare taille 3 (grande).
Rare size 3 (large).
A Size 3 avalanche is large enough to bury a car or destroy a small building.
Dû à une vielle sous-couche fragile persistante en cours d'humidification.
Due to an old persistent weak layer currently undergoing wetting.
*Sous-couche fragile persistante* is the technical term for a Persistent Weak Layer (PWL). *En cours d'humidification* means water is percolating into it, making it unstable.
quelques plaques de fond dans les zones herbeuses ou les dalles rocheuses, à toute heure du jour ou de la nuit.
a few glide-snow avalanches in grassy areas or rock slabs, at any time of day or night.
*Plaques de fond* are glide-snow avalanches that release at the ground level. Unlike wet snow slides, these are not strictly tied to daytime heat.
En dessous 2500 m.
Below 2500 m.
Specific elevation limit for glide-snow activity.
Taille 2 (moyenne).
Size 2 (medium).
Size 2 is large enough to bury or injure a person.
Déclenchements provoqués :
Triggered releases:
Refers to avalanches caused by a person (skier, hiker, etc.).
avalanches de neige humide sous 4200 m en sud et 3000 m en nord.
wet snow avalanches below 4200 m in the south and 3000 m in the north.
The danger zone matches the natural release elevations.
Facile à déclencher au soleil.
Easy to trigger in the sun.
*Au soleil* emphasizes that solar warming is the primary trigger mechanism reducing snow cohesion.
Départ ponctuel sous les skis.
Point release under the skis.
Suggests that the primary human-triggered hazard is loose wet snow sluffs rather than hard slabs.
Taille 1 à 2.
Size 1 to 2.
Small to medium human-triggered slides.
Causé par le réchauffement et le rayonnement solaire.
Caused by warming and solar radiation.
Reiteration of the primary drivers of the wet snow avalanche problem.
ensoleillé.
sunny.
The fundamental weather condition driving the spring cycle.
Cumulus au-dessus du relief l’après-midi.
Cumulus clouds over the terrain in the afternoon.
*Relief* refers to the mountains/terrain. Convective clouds are common as the day warms up.
Au maximum 12°C à 2000 m.
Maximum 12°C at 2000 m.
A very high temperature for this altitude, explaining the rapid melting and wetting of the snowpack.
Enneigement :
Snowpack / Snow coverage:
*Enneigement* refers to the general state and quantity of snow on the ground.
Pour la saison, l’enneigement est déficitaire sous 3000 m
For the season, the snowpack is below average below 3000 m
*Déficitaire* means there is less snow than the historical average for this time of year.
On peut chausser les skis au-dessus de 2000 m en sud et 1600 m en nord.
Skiing is possible above 2000 m on south aspects and 1600 m on north aspects.
*Chausser les skis* literally means "to put on the skis," indicating the snow line for practical travel.
Qualité de la neige ce dimanche matin :
Snow quality this Sunday morning:
Spring bulletins often specify the time, as quality changes drastically between morning and afternoon.
sous 2000 m, neige de névé avec un bon regel nocturne.
below 2000 m, firn/neve snow with a good overnight freeze.
*Névé* refers to dense, old snow. *Regel nocturne* (overnight freeze) is crucial for safety; it creates a supportive crust.
sous 3000 m en nord et 4000 m en sud, neige de printemps avec un bon regel nocturne.
below 3000 m on north aspects and 4000 m on south aspects, spring snow with a good overnight freeze.
*Neige de printemps* (corn snow) is snow that thaws by day and freezes by night.
au-dessus de 3000 m en nord et 4000 m en sud, neige encore froide avec de nombreux endroits où la glace ressort.
above 3000 m on north aspects and 4000 m on south aspects, snow is still cold with many areas where ice is exposed.
*La glace ressort* literally "ice comes back out," meaning the wind or melting has exposed old ice layers, indicating slick conditions.
French Term English Term Definition Source
Départ spontané Naturally triggered avalanches Avalanche not caused by external forces, e.g. snowfall or loss in firmness due to weather conditions. European Avalanche Warning Services
déclenchable Skier-triggered releases An avalanche caused by the weight of a person (skier, snowboarder, hiker) or by explosives. The additional load collapses a weak layer, causing the slab above to fracture and slide. AvalancheClarity Static Glossary
Neige ancienne (Sous-couche fragile persistante) Persistent Weak Layer The persistent weak layers problem is related to the presence of persistent weak layers in the old snowpack. These weak layers typically include buried surface hoar, depth hoar or faceted crystals. Weak layers can persist for weeks to months; possibly most of the winter season. European Avalanche Warning Services
Avalanche de neige mouillèe Wet snow avalanches Avalanche of wet snow masses. European Avalanche Warning Services
Enneigement Snow conditions The depth and distribution of snow on the ground across a mountain range. Varies with elevation, aspect, and snowfall history. AvalancheClarity Static Glossary
ensoleillement solar radiation Light and heat energy from the sun. Much of this is in the Ultraviolet part of the electromagnetic spectrum. Avalanche Center (US)
marqué considerable Snowpack is moderately to poorly bonded on many steep slopes. Triggering is possible even from low additional loads, particularly on indicated steep slopes. In certain situations, some large natural avalanches are possible. European Avalanche Warning Services
reptation Glide Slabs A cohesive slab of snow, often consisting of the entire snowpack, that lacks significant support or friction from the bed surface. Avalanche Canada
Regel Refreezing Overnight freezing of the snow surface forming a hard crust. Refreezing temporarily stabilises the snowpack but strength decreases with daytime warming. AvalancheClarity Static Glossary
Manteau neigeux Snow cover Snow deposited on the ground in a multiplicity of layers. European Avalanche Warning Services
Hauteur de neige Snow depth Thickness of the snowpack measured vertically. European Avalanche Warning Services
Couches fragiles Weak layer Snowpack layer in which the crystals are poorly bonded and the layer has the potential to fail. European Avalanche Warning Services
Stabilité Stability The strength of a snowpack to withstand internal and external disturbances.Stability is determined by firmness vs. stress inside a snow layer. European Avalanche Warning Services
très fort very high Snowpack is generally unstable. Many large natural avalanches are expected, even on moderately steep terrain. Extremely dangerous conditions — avoid all avalanche terrain. European Avalanche Warning Services
Neige humide Wet snow The wet snow problem is related to the weakening of the snowpack due to the presence of liquid water. Water infiltrates the snowpack due to high radiation impact (sunshine) which leads to melt or rain (advecting energy into the snowpack leading to melt as well). European Avalanche Warning Services
limité moderate Snowpack is moderately well bonded on some steep slopes, otherwise generally well bonded. Triggering is possible with high additional loads, particularly on indicated steep slopes. Large natural avalanches unlikely. European Avalanche Warning Services
Exposé Exposed Exposure to wind, sun, avalanches or other general danger. European Avalanche Warning Services
Exposition Aspects Direction in which a slope faces as indicated by compass direction of the fall line; i.e. a north slope faces in a northerly direction. European Avalanche Warning Services
moyen medium IACS/UNESCO
Névé Firn Snow accumulated in recent years, mostly atop glaciers, intensely metamorphosed and denser because of melting and refreezing, as well as from pressures of overlying snow masses. European Avalanche Warning Services
Risque Risk Likelihood of occurrence combines mathematical probability, risk exposure and possible damages. European Avalanche Warning Services
faible low Snowpack is generally well bonded and stable. Triggering is generally possible only from high additional loads in a few isolated steep extreme terrain features. Only small natural avalanches possible. European Avalanche Warning Services
sèche dry IACS/UNESCO
1 2 3 4 5

Bulletin d'estimation du risque d'avalanche

(valable en dehors des pistes balisées et ouvertes)

MASSIF : Mont-Blanc

rédigé le samedi 25 avril 2026 à 16 h.

Pour consulter la vigilance en cours, veuillez vous rendre sur le site https://vigilance.meteofrance.fr/fr

Estimation des risques pour le dimanche 26 avril 2026

Conditions printanières


            Risque détaillé
NESO

Indices de risque : 5 très fort - 4 fort - 3 marqué - 2 limité - 1 faible -- En noir : les pentes les plus dangereuses

Indice de risque faible évoluant en limité.

Départs spontanés : avalanche de neige humide

Déclenchements skieurs : petits départs en neige humide sous les skis

Stabilité du manteau neigeux jusqu'au dimanche 26 avril au soir

Situation avalancheuse typique :Neige humideNeige humideCouche fragile persistanteCouche fragile persistante

Départs spontanés : 
* rares avalanches de neige humide, plus nombreuses au fil du réchauffement et du rayonnement solaire. En dessous de 3000 m en nord et 4200 m en sud. Taille 1 à 2 (petite à moyenne). Dans la tranche 2300/3000 m, dans les versants est, ouest et nord, de petits départs ponctuels peuvent déclencher, en cascade, une plaque de plus grande ampleur. Rare taille 3 (grande). Dû à une vielle sous-couche fragile persistante en cours d'humidification. 
* quelques plaques de fond dans les zones herbeuses ou les dalles rocheuses, à toute heure du jour ou de la nuit. En dessous 2500 m. Taille 2 (moyenne). 

Déclenchements provoqués : 
* avalanches de neige humide sous 4200 m en sud et 3000 m en nord. Facile à déclencher au soleil. Départ ponctuel sous les skis. Taille 1 à 2. Causé par le réchauffement et le rayonnement solaire. 

Qualité de la neige

    Enneigement : 
Pour la saison, l’enneigement est déficitaire sous 3000 m 
On peut chausser les skis au-dessus de 2000 m en sud et 1600 m en nord. 

Qualité de la neige ce dimanche matin : 
* sous 2000 m, neige de névé avec un bon regel nocturne.
* sous 3000 m en nord et 4000 m en sud, neige de printemps avec un bon regel nocturne. 
* au-dessus de 3000 m en nord et 4000 m en sud, neige encore froide avec de nombreux endroits où la glace ressort. 
  

Aperçu météo pour le dimanche 26 avril

nuitmatinaprès-midisoir
ensoleillé. Cumulus au-dessus du relief l’après-midi. Au maximum 12°C à 2000 m.
Pluie-Neige----
Iso 0°C3100 m3300 m3200 m3200 m
Vent 2000 m 5 km/h 10 km/h 5 km/h 10 km/h
Vent 4000 m 20 km/h 20 km/h 20 km/h 10 km/h

Epaisseur de neige hors-piste

sam. 25 avril N S 220 cm 2500 m 110 cm 2000 m 0 cm 1500 m 140 cm 2500 m 40 cm 2000 m 0 cm 1500 m Altitudes d'enneigement continu : Versant NORD : 1600 m Versant SUD : 1900 m

Précipitations à 1800 m

Quantités cumulées en 24 heures Neige fraîche à 1800m Neige fraîche Min Neige fraîche Max Pluie 5 10 Neige (cm) / Pluie (mm) 0 0 0 mer. 22 à 6h 0 0 0 jeu. 23 à 6h 0 0 0 ven. 24 à 6h 0 0 0 sam. 25 à 6h 0 0 0 dim. 26 à 6h 0 0 0 lun. 27 à 6h

Tendance du lundi 27 avril

Indice de risque limité

Lundi : temps sec et rares cumulus l’après-midi. Isotherme 0°C vers 3000 m. ⇒ poursuite de l’humidification du manteau neigeux

Conditions nivo-météo des 7 derniers jours

Les 7 derniers jours

dim. 19/04lun. 20/04mar. 21/04mer. 22/04jeu. 23/04ven. 24/04sam. 25/04
03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h03h09h15h21h
Météo
Vent
(km/h)
à 4000m
35354040506060505050506070604030304030201020202030404040
Vent
(km/h)
à 2000m
1015201515152015101520101010555101010551055101510
Iso 0°CLimite pluie-neige
Altitude en m
3200
2400
1600
800
0
dim. 19/04lun. 20/04mar. 21/04mer. 22/04jeu. 23/04ven. 24/04sam. 25/04
Neige
fraîche (6h)
0 cm
Risque
d'Avalanche
Enneigement versant Nord et Sud à  1500m···   2000m- - -   2500m
Hauteur totale
de neige (cm)
320
240
160
80
0
1010105150140140130130120110260250250240240230220
dim. 19/04lun. 20/04mar. 21/04mer. 22/04jeu. 23/04ven. 24/04sam. 25/04
Limite de l'enneigement - Versant Nord   Limite de l'enneigement - Versant Sud
Limite
d'enneigement (m)
2400
2100
1800
1500
1200
900
600
300
0
1600160015001500150015001600 1700180018001800180018001900
dim. 19/04lun. 20/04mar. 21/04mer. 22/04jeu. 23/04ven. 24/04sam. 25/04
Iso 0°C LPN Météo
à
1800m
Vent à
2000m
Vent à
4000m
dim. 19/0403h2 800-
10
35
09h2 800-
15
35
15h2 7002 400
20
40
21h2 600-
15
40
lun. 20/0403h2 700-
15
50
09h2 600-
15
60
15h2 600-
20
60
21h2 700-
15
50
mar. 21/0403h2 700-
10
50
09h2 700-
15
50
15h2 600-
20
50
21h2 600-
10
60
mer. 22/0403h2 600-
10
70
09h2 600-
10
60
15h2 700-
5
40
21h2 700-
5
30
jeu. 23/0403h2 700-
5
30
09h2 900-
10
40
15h3 000-
10
30
21h3 000-
10
20
ven. 24/0403h3 000-
5
10
09h3 200-
5
20
15h3 200-
10
20
21h3 200-
5
20
sam. 25/0403h2 900-
5
30
09h2 800-
10
40
15h2 900-
15
40
21h3 000-
10
40
Risque
avalanche
Limite enneigement Enneigement à
2000m
Neige fraîche à
1800m
dim. 19/04N : 1 600 m
S : 1 700 m
N : 150 cm
S : 80 cm
0 cm
lun. 20/04N : 1 600 m
S : 1 800 m
N : 140 cm
S : 70 cm
0 cm
mar. 21/04N : 1 500 m
S : 1 800 m
N : 140 cm
S : 70 cm
0 cm
mer. 22/04N : 1 500 m
S : 1 800 m
N : 130 cm
S : 60 cm
0 cm
jeu. 23/04N : 1 500 m
S : 1 800 m
N : 130 cm
S : 60 cm
0 cm
ven. 24/04N : 1 500 m
S : 1 800 m
N : 120 cm
S : 50 cm
0 cm
sam. 25/04N : 1 600 m
S : 1 900 m
N : 110 cm
S : 40 cm

La documentation utile à la bonne lecture de ce BRA est disponible sur le guide avalanche 2025

Rédigé par Météo-France avec la contribution des observateurs du réseau nivo-météorologique. Partenariat : ANMSM (Maires de Stations de Montagne), DSF (Domaines Skiables de France), ADSP (Directeurs de Pistes et de la Sécurité des Stations de Sports d'Hiver) et autres acteurs de la montagne.