Crown Locations

<< Avalanche Start Zones | Avalanche Avoidance | Slope Steepness >>

Potential crown fracture points occur at stress concentrators such as trees, taper points, and rocks. Thin snow can also lead to higher temperature differentials in the snow pack, particularly early season. This causes water vapour to be driven through the snow from warm to cold layers forming hoar or faceted crystals or gobelets (so called because they have the strength of champagne gobelets – strong in compression but weak in shear). These can form persistent weak layers in the snow pack that can be hard to identify by digging snow pits. The process is reversible but because it took a lot of energy to form the crystals (strong temperature gradient) taking that energy source away means it takes a long time to reverse the process.

We often ski between islands of safety. But some guides prefer to avoid features such as rock outcrops precisely because they may hide weak layers. This is where the guide’s detailed knowledge of weather conditions in the area over the season can be so valuable.

Categories: Snow Safety