Snow conditions 8.12.2021

General avalanche danger level - Wednesday, 8 December 2021
Danger is level 3 on the European five-level scale - CONSIDERABLE.
Main problem: fresh snow, wind slab
Danger pattern: Cold weather, poorly bonded fresh snow with wind

Risk assessment
Avalanche danger above the treeline is CONSIDERABLE, level 3, lower down mostly MODERATE, level 2. Particularly dangerous are wind slab areas, which due to winds of variable direction are on all aspects. Wind slab is locally covered by snow, so the danger is hard to recognise. Especially where there is less fresh snow, a wind slab avalanche can be triggered by a minor load. Steep slopes where smaller dry snow avalanches can still be triggered are dangerous. This particularly applies to areas where snow fell onto a hard, crusted surface. Due to more abundant snowfall and wind, conditions will change rapidly today.

Snow conditions
On Monday and Tuesday, sunny, cold and locally windy weather prevailed in the mountains. The snowpack settled and metamorphosed only slowly, snow softened slightly on pronounced northerly slopes below about 1200 m a.s.l. and froze overnight. There is still plenty of dry and poorly metamorphosed snow, which in higher terrain was transported by wind. Initially northerly wind blew, then northwesterly, now a strengthening southwesterly wind is transporting larger quantities of snow again. On wind-exposed sites, fine snow is heavily drifted, new wind slabs have formed on all aspects. Snow cover reaches down to the valleys.

Forecast weather evolution
Today, clouding from the west in the morning and forenoon everywhere, in the afternoon snow will start in the western part of our mountains. Overnight to Thursday, snowfall will spread to the east too. On the Snežnik area, snow will temporarily turn to rain. Moderate southerly wind will blow, strengthening in the afternoon. Temperature at 1500 m around -2, at 2500 m around -4 °C. Overnight more abundant snowfall. Moderate wind, strong in high mountains from southerly directions, will blow. Tomorrow also mostly cloudy and foggy, towards evening clouds may break up. Occasionally light snowfall, snow showers possible. In the morning and forenoon weak wind from southerly to easterly directions, then weak to moderate wind from northerly directions. Temperature at 1500 m around -4, at 2500 m around -9 °C. On Friday dry, changing cloudiness. Initially probably more low and mid-level cloud, in the afternoon clouding in higher atmospheric layers. Wind weak to moderate, turning from easterly to southwesterly. Slightly colder. At 1500 m around -6, at 2500 m around -12 °C. Also at the end of the week, dry, cold and very windy weather is expected.

Tendency of snow conditions
Snow conditions will change rapidly today due to wind and later snowfall. In total, 20 to 50 cm of dry snow is forecast by Thursday morning. The most is expected in the area of the southern and western Julian Alps and the prealpine region of western Slovenia. During snowfall, strengthening southerly winds will transport snow and build new cornices, wind slabs and drifts on northern slopes. The danger of avalanche release will INCREASE, also in the subalpine zone CONSIDERABLE level 3. It will be particularly dangerous where fresh snow falls onto a hard and crusted surface. On Thursday daytime, another 5 to maximum 10 cm of snow may fall. Also in the coming days, snow will remain dry due to cold weather and metamorphose and settle only slowly. Primarily on wind-exposed sites, drifts will form. At the end of the week, strengthening northerly winds will blow, extensive areas of wind-blown snow are expected. Conditions will remain demanding.

Next issue: Friday, 10 December 2021

Source: ARSO