Snow conditions 25.12.2020

The danger is level 3 on the European five-level scale - CONSIDERABLE.

Main problem: wind-blown snow, new snow, weak layers



Risk assessment

Avalanche danger is currently above about 1800 m CONSIDERABLE, level 3, lower down MODERATE, level 2. In the high mountains, a considerable amount of new snow has fallen on a hard snow base, so spontaneous dry snow slab avalanches are also expected. During snowfall yesterday, a moderate to strong southwesterly wind was blowing, today a northeasterly wind has started. In the high mountains, slabs have formed on many slopes, where a slab avalanche can be triggered even by minor loading. Lower down, snowfall has started today on a wet snow base. The new snow has bonded better to the base, so the danger is lower in the mid-mountains.



Snow conditions

Yesterday, with moderate to strong southwesterly wind, snow was falling only in the high mountains above about 2000 m sea level, lower down it was raining heavily in places. With the passage of the front overnight today, the snow line dropped to some alpine valleys by morning. So far, a total of 30 to 55 cm has fallen in the high mountains, 10 to 25 cm in the mid-mountains. In the high mountains, snow fell on a hard base, so the new snow has bonded poorly. During snowfall in the high mountains, a moderate to strong southwesterly wind blew, building new deposits and cornices on northeast slopes. Today, a northeasterly wind has started, so snow deposits are also beginning to form on southwest slopes. In the mid-mountains, wetter snow is falling on a soaked snow base, so it has bonded better there. Temperature is slowly dropping, so drier snow is falling.



Forecast weather development

Today it will be cloudy and foggy with snowfall, which will slowly weaken in the afternoon. An additional 10 to 25 cm of snow will fall. A moderate to strong northeasterly wind will blow. It will cool down. At midday, temperature at 1500 m will be around -2, at 2500 m -9 °C. On Saturday during the day, it will partially clear. A moderate to strong northeasterly wind will blow. It will be cold, temperature at 1500 m around -7, at 2500 m -12 °C. On Sunday, mostly clear, more clouds only in the Snežnik area. A weak to moderate southeasterly wind will blow. Temperature at 1500 m around -7, at 2500 m around -8 °C. On Monday during the day, heavy snowfall will resume. The snow line will rise above 1000 m in the south. We expect around 50 cm of new snow especially in the Julian Alps. Accompanying this will be a strong to very strong wind from southern directions. The weather will remain unstable with occasional snowfalls throughout the rest of the week.



Trend in snow conditions

Avalanche release danger will remain CONSIDERABLE, level 3 in the high mountains also for the weekend end due to additional snowfall and strengthened northeasterly, lower down MODERATE, level 2. Especially southwest slopes will be dangerous, where new snow deposits will form. Due to the wind, the snow surface will be heavily redistributed in many places. A crust will form, on exposed spots the wind will blow snow down to the hard base. Transformation and stabilization of the snow cover will be slow due to cold weather. On Monday, weather and avalanche conditions will be distinctly unfavorable. Avalanche release danger will most likely INCREASE further.



Next issue: Monday, 28. 12. 2020



Source: ARSO