Goldberg Group Central

Trigger-sensitive snowdrift accumulations in high alpine regions

Trigger-sensitive snowdrift accumulations in high alpine regions

Avalanche danger increases with ascending altitude: above 1500 m danger is MODERATE, above 2400 m danger is CONSIDERABLE. Up to 2400 m the main danger is from small-to-medium glide snow avalanches, triggerable at any time of day or night. The snowpack is thoroughly wet, even superficial wet-snow avalanches are possible. As of 2400m, fresh and (in high alpine regions) also older snowdrift accumulations require attentiveness. They occur on NW/N/E facing slopes both near to and distant from ridgelines, behind abrupt drops in the terrain and in wind-loaded gullies and bowls. A small-to-medium sized slab avalanche can be triggered by large additional loading (by minimum additional loading in extremely steep terrain).

On Thursday it was very warm, rainfall extended up to 2800m. A thin ice crust formed. The snowpack (insofar as there is one) is 0-degree isotherm. Above 2000 m there was a few cm of fresh cold snow registered. Bonding to the base deteriorates with ascending altitude. Southerly foehn wind on Friday transported some of the fresh fallen snow, later westerly winds. Potential fracture points in the melt-freeze crusts of the old snowpack and in high alpine regions in the blanketed fresh snow.

On Saturday, variable visibility, repeated bouts of snow showers and rain. Snowfall level will lie between 1400 and 1800 m. Winds will be blowing at 30-50 km/hr in exposed zones, up to 70 km/hr in the Northern Alps at high altitudes. At 2000m: -3 to 0 degrees; at 3000m: -9 degrees.

Little change expected. Depending on altitude, snowdrifts and wet-snow problem requires attentiveness. Poor visibility makes on-site assessment more difficult.