The forecasters at Météo France recently conducted ski touring outings in the Northern and Southern Alps to analyze snow conditions and avalanche activity. Now there are daily bulletins for each mountain range but it is interesting to see some of the information that goes into those forecasts.
Northern Alps: Caution at Higher Elevations
Below 2000 meters they found conditions that are relatively stable, with superficial wet slides occurring on very steep slopes. However, above this altitude, the situation becomes more complex. A thin layer of fresh snow (5 to 10 cm) is cohesive under the influence of wind and mild temperatures. As a result, cracks quickly appear under skis near ridges, indicating the potential for small localized slabs.
The most concerning aspect is the snowpack structure. A survey conducted at 2550 m revealed about 1 m of snow in a wind-affected area, with a particularly fragile base: 50 cm of angular grains. A compression test showed a rupture on the 14th tap within these weak layers composed of faceted crystals and depth hoar, indicating a residual risk of deep fractures. This was on the Pointe de la Masse near les Menuires but these conditions resemble those observed further east, where stability is compromised by these fragile buried structures and has caused a number of recent incidents.
Southern Alps: More Stable Snowpack but Some Instabilities
In the Southern Alps, observations are more reassuring, despite some surface releases in the fresh snow, particularly in steep terrain. These slides remain of moderate size and do not pose significant danger.
A survey conducted at 2170 m under the north face of Grand Ferrand in the Devoluy range indicated a snow depth of 90 cm. The upper layer (40 cm) consists of fairly hard recent snow, with some instabilities that are difficult to trigger. At greater depths, the snowpack is marked by a crust several tens of centimeters thick, a result of late January rains. While small weak layers are present near the ground, their impact on overall stability remains limited thanks to this protective crust.
Conclusion
Ski conditions vary significantly between the Northern and Southern French Alps. While the Northern Alps require increased caution due to still-active weak layers at higher elevations, the Southern Alps benefit from better snowpack cohesion, although some localized instabilities persist. Careful terrain management and a precise analysis of local conditions remain essential for safe skiing.
