Lohkolumivyöryt

Lohkolumivyöryt, known in English as slab avalanches, are a type of snow avalanche characterized by the release of a large, cohesive block of snow. This block then fractures into smaller pieces as it descends the slope. They are a significant hazard in mountainous regions, particularly during winter and spring.

The formation of a lohkolumivyöry typically involves a weak layer of snow buried beneath a stronger, denser slab of snow. This weak layer can be formed by various factors, such as surface hoar, faceted snow crystals, or a thin ice crust. When sufficient stress is applied to the slab, it can break away from the underlying weak layer, initiating the avalanche. This stress can be natural, such as a heavy snowfall or wind loading, or human-induced, such as the weight of a skier or snowboarder.

The slab then detaches from the slope and begins to slide downhill. As it accelerates, internal stresses cause the slab to break into numerous smaller fragments, creating a distinct granular flow. The size and speed of a lohkolumivyöry can vary greatly, depending on the size of the slab, the steepness of the slope, and the characteristics of the snowpack. These avalanches can travel long distances and possess immense destructive power, capable of burying trees, buildings, and individuals.

Identifying potential avalanche terrain is crucial for safety. This includes slopes that have recently received significant snowfall or wind loading, areas with visible signs of instability such as cracking or "whoomphing" sounds, and slopes exceeding 30 degrees in inclination. Backcountry travelers should always check avalanche forecasts, carry essential safety equipment, and have proper training before venturing into avalanche-prone areas.