Verwall Mountains West

Rapid increase in likelihood of wet-snow avalanches triggering

Rapid increase in likelihood of wet-snow avalanches triggering

Mostly favorable conditions prevail in the morning, low danger. Due to warmth and solar radiation, likelihood of wet-snow and glide-snow avalanches triggering naturally will rapidly increase over the course of the morning. During daytime hours, increasingly frequent wet-snow avalanches can be expected. If these sweep along the wet snowpack they can grow to large size. In addition, glide-snow avalanches can be expected, medium-to-large. Avoid zones below glide cracks. Beware huge cornices. Isolated danger zones for dry-snow avalanches can be triggered in the uppermost layers of the snowpack, esp. on steep shady slopes in high-alpine regions. All backcountry activities should be terminated early in the day.

Due to outgoing radiation a superficially burdenable melt-freeze crust can form at night, rapidly softening in the morning depending on aspect and altitude and steepness gradient. Beneath the fresh snow the snowpack is thoroughly moist down to the ground below 2600 m. Danger zones for dry-snow avalanches occur esp. on steep shady slopes at high and high-alpine altitudes.

Nocturnal hours: Outgoing longwave radiation is adequate, skies are clear to slightly cloudy, the air is dry. But temperatures are very high. Sunday daytime: The air will remain warm (zero-degree leval at 3600m), sunshine, diffuse light conditions, convective cloud build-up in afternoon. At 2000 m: at midday 10-13 degrees. Moderate westerly winds.

On Monday a cold front will move in, bringing showers which can become heavy later in the day. The air will still be warm, snowfall level descending only slowly to 2300 m. The SW winds will be brisk to strong. Wet-snow avalanche danger will rise temporarily. In high alpine regions, trigger-prone snowdrifts will accumulate.