Avalanche Bulletin from Wednesday, 01/17/2018, at 7:30 AM
WHY? - Danger patterns (dp):
High danger where snowfall is heaviest. Treacherous backcountry situation!
Fresh snow and storm wind have increased avalanche danger in Tirol. In the western regions the danger level is high, without doubt during the night avalanches triggered naturally. Persistent snowfall and snow transport, plus more naturally triggered avalanches, can be expected during the day. Increasingly frequent on W/N/E facing slopes, the weak layers will fracture; fractures down to more deeply embedded layers are unlikely. Thus, the avalanches will mostly be medium sized, large-sized only in the regions where snowfall is heavy. In the regions west of the Wipp Valley and in the eastern sector of the Northern Alps, avalanche danger could also rise to level 4 today. In the remaining regions of Tirol, a critical (upper notch) level 3 prevails. On W/N/E facing slopes, the weight of one sole person is probably enough to trigger an avalanche. Even remote triggerings are possible from flat terrain. We advise the inexperienced to remain on secured ski runs. In southern East Tirol, conditions are better, but the fresh snowdrifts must be studiously avoided in steep terrain. On steep, grassy slopes the danger of gliding avalanches still threatens.
Over the last 24 hours there has been snowfall in the western and northern regions of Tirol (30-50 cm, from place to place up to 70 cm). In the other parts of North Tirol and in northern East Tirol there was 10-20 cm of fresh snow registered; in southern East Tirol only a small amount. Stormy winds accompanied the snowfall, and the winds will persist. Fresh snow and snowdrifts were frequently deposited on top of an unfavourable old snowpack surface, particularly on W/N/E facing slopes atop surface hoar or a layer of faceted crystals. The proneness to triggering is very high there! In some places, graupel is mixed into the falling snow. On E/S/W facing slopes this can create a weak layer in the snowpack. Rainfall at low altitudes has weakened and deteriorated the snowpack somewhat.
Alpine Weather Forecast (ZAMG-Weather Service Innsbruck)
Fog, in places heavy snowfall, strong winds dominate the scene today. Most snowfall is anticipated in Silvretta, Arlberg and Lechtal Alps. The fresh snow is being massively transported, so the ultimate snow depths will be highly irregular. In the Carnic Alps and Dolomites, mostly dry but also very windy. At 2000 m: -8 to -11 degrees; at 3000 m: -13 to -18 degrees. Stormy W/NW winds, reaching gale strength in gusts.
Treacherous situation in outlying terrain
[Author: Patrick Nairz]
[Translated by Jeffrey McCabe]