Bregenzerwald Mountains

Still weak layers in old snowpack on high-altitude shady slopes

Still weak layers in old snowpack on high-altitude shady slopes

Weak layers in the old snow can be triggered in some places even by one sole skier, avalanches released can attain medium size. Danger zones occur esp. in steep shady terrain. Frequency of danger zones has significantly decreased. Avalanches can also fracture down to weaker layers more deeply embedded in the snowpack and grow to large size. Transitions from shallow to deep snow, e.g. at entries into gullies and bowls, also require high caution. Fresh, small drifts in high-altitude exposed zones should be avoided, esp. in shady terrain. A cautious route selection is recommended. Due to higher temperatures and solar radiation, moist loose-snow and glide-snow avalanches are possible during the day on very steep sunny slopes.

Temperatures have risen noticeably at high altitude, the proneness to triggering has diminished. In the upper part of the snowpack are expansively metamorphosed (faceted) crystals. These are most triggerable in transition from shallow to deep snow. These zones are not visible to the naked eye. On very steep sunny slopes there is a thin melt-freeze crust on the surface. Elsewhere the snowpack is often powdery. At intermediate altitudes there is surface hoar. Due to solar radiation and daytime warming the snowpack softens on sunny slopes.

Nocturnal hours: cloudless nighttime skies and dry air will bring high outgoing longwave radiation. Monday: sunny weather, mostly cloudless skies. Dry air masses guarantee outstanding visibility. Temperatures will rise. At 2000 m: -1 to +4 degrees. Zero-degree level will rise to nearly 3000 m. Light NE winds.

Tuesday and Wednesday will be sunny, zero-degree level will abide at about 3000 m. Through Wednesday the winds will be light. On Thursday, intensifying W/NW winds. Danger of dry-snow avalanches will diminish. As temperatures rise and solar radiation intensifies, wet-snow and glide-snow avalanche danger will increase during the course of the day.