Rieserferner Mountains

Wind slabs and weakly bonded old snow are to be critically assessed.

Wind slabs and weakly bonded old snow are to be critically assessed.

The wind slabs of the last few days are prone to triggering. Avalanches can in some places be released, even by a single winter sport participant and reach large size in isolated cases. The avalanche prone locations are to be found in particular on wind-protected west, north and east facing slopes at high altitudes and in high Alpine regions. Caution is to be exercised on steep, little used shady slopes. In regions neighbouring those that are subject to danger level 2 (moderate) the avalanche prone locations are more rare and the danger is lower. In the regions with a lot of snow gliding avalanches and moist snow slides are possible. Backcountry touring and other off-piste activities call for extensive experience in the assessment of avalanche danger and restraint. In the evening as a consequence of new snow and wind there will be an increase in the avalanche danger.

The fresh and older wind slabs are lying on top of a weakly bonded old snowpack on west, north and east facing slopes. On Saturday further wind slabs formed as well. In some cases the various wind slabs have bonded still only poorly with each other and the old snowpack. The old snowpack consists of faceted crystals, especially on wind-protected shady slopes. Whumpfing sounds and the formation of shooting cracks when stepping on the snowpack serve as an alarm indicating the danger. Stability tests and field observations confirm this situation.

Increase in avalanche danger as a consequence of new snow and strong wind. The snowpack will become increasingly prone to triggering. In the regions exposed to heavier precipitation the avalanche danger will increase to level 4 (high).