25/05/2021
Ski-touring & Freeride:
lots of ski tracks = safe slope ??
Many ski-mountaineers and freeriders think that a slope with lots of ski tracks is safe from avalanche danger.
The idea is that ski tracks break the continuity of the snow surface, preventing the formation of snow slabs. Snow slabs take place when the snowpack is rather compact, featuring a consistent cohesion (strong bonds among snow crystals).
That’s an oversimplification and is sometimes NOT true (as professional snowboarder Xavier De La Rue points out in his post), for a number of reasons.
If ski tracks dig just at the upper layer of the snowpack, the lower layers may be untouched and, if snow has cohesion, they can be triggered as a slab.
Or there might be the conditions for triggering an avalanche not of the slab type, for example a wet snow avalanche being triggered at a distance.
Or, simply put, the snow conditions may have changed from the ones which were found by the skiers making the first tracks.
The conclusion is: never trust a slope just because of the many ski tracks. Snow stability parameters have to be carefully assessed regardless of ski tracks and, if you do not have the expertise to do that, hire a guide...
