Nock Mountains

Blanketed loose snow is potential fracture point for slab avalanches

Blanketed loose snow is potential fracture point for slab avalanches

Danger of avalanches is a function of the amounts of fresh snow and wind impact. Above 2000 m: CONSIDERABLE, below that altitude down to the treeline MODERATE. The frequency of danger zones increases with ascending altitude. Avalanche prone locations (due to snowdrifts) are found in gullies and steep bowls and on steep ridgeline slopes in NE/E/S aspects. An avalanche can be triggered even by minimum additional loading and grow to medium size or larger. In the regions of the Main Tauern Ridge where snowfall has been heaviest, naturally triggered Size-3 avalanches can trigger naturally at high altitudes.

There has been 20-40 cm of fresh snow registered on top of a frequently melt-freeze encrusted, sometimes iced-over snowpack surface, in the Main Tauern Ridge zones up to 50 cm. Bonding is largely favorable due to mild temperatures, but W/N winds have deposited cold, bonded snow on top of it, often interspersed with graupel. In this loose layer fractures could propagate in the snowdrifts. Beneath the melt-freeze crusts (now covered) there is soft, faceted snow which can also serve as a fracture point.

On Thursday, light snowfall (strong in some places, max. 15 cm). Visibility initially impaired. The W/NW winds blowing at 30-40 km/hr. Wintery cold temperatures. At 2000 m: -11 degrees; at 3000 m: -18 degrees. On Friday, sunny from the start, flawless visibility. Winds no longer disturbing. Cold! At 2000 m: -8 degrees; at 3000 m: -12 degrees.

The snowdrift problem remains upright at high altitudes, due to the persistently low temperatures. Sunny weather on Friday should not deceive: dangers lurk!