Kerrostapisto

Kerrostapisto is a Finnish term that literally translates to "layer splintering" or "layer detachment." It describes a phenomenon occurring in the upper layers of snowpack, particularly in mountainous or hilly regions. This can happen when a weak layer of snow, often resulting from a specific type of snowfall or temperature gradient, lies beneath a heavier, more cohesive layer of snow.

The formation of Kerrostapisto is influenced by various factors including temperature fluctuations, humidity, and the type of precipitation. For instance, a layer of surface hoar, which forms during clear, cold nights when moisture in the air freezes directly onto the snow surface, can create a very weak layer. If a subsequent snowfall adds significant weight on top of this hoar layer, the stress can exceed the weak layer's strength, leading to its collapse.

This detachment can result in the upper snow layers sliding off the weaker underlying layer. In a mountaineering or backcountry skiing context, Kerrostapisto is a significant indicator of potential avalanche danger. The presence and nature of these weak layers are critical considerations for avalanche safety assessments. Understanding the conditions that lead to Kerrostapisto is vital for anyone traveling in snow-covered terrain where avalanches are a risk.