Persistent weak layers
- Above 2,200 m
Weak old snowpack layers persist
Weak old snowpack layers persist
Marked weak layers in the old snowpack can still easily be triggered by one single winter sports enthusiast, especially above 2200m on steep, little-skied on slopes. The danger zones are not visible. Remote triggerings are possible. Older small snowdrift accumulations blanketed by fresh snow occur increasingly in ridgeline terrain and in wind-loaded gullies and bowls. Avalanches which release can fracture to deeper layers in the old snowpack and grow to medium size. Whumpf noises and fractures when treading on the surface are alarm signals. Activities in backcountry demand careful evaluation of the terrrain and assessment of the dangers. Restraint is advised. Due to daytime warming and solar radiation, isolated loose-snow avalanches can be expected in very steep terrain.
A small amount of fresh snow and fresh drifts blanket older, generally somewhat stabilized snowdrift accumulations. The often lie deposited on loosely-packed snow or surface hoar at higher altitudes and atop a weak old snowpack surface (particularly on steep shady slopes). On sunny slopes and generally at lower altitudes the snowpack surface generated a melt-freeze crust during the nighttime hours.
Weak high-pressure conditions will bring sunny mountain weather, intermittent cirrus clouds passing through Temperature at 2000m: -2 degrees; at 3000m: -8 degrees. Light southerly-to-easterly winds at high altitudes.
As a result of mild temperatures with only light winds, snowdrift accumulations increasingly stabilizing. However, weak layers persist in the snowpack, remain prone to triggering.
Bulletin data: Avalanche Warning Service Vorarlberg (CC BY 4.0)