Snow conditions 26.02.2024

General danger level - Monday, 26.2.2024
The danger is level 3 on the European five-level scale - CONSIDERABLE.
Main problem: wind slab, new snow, weak layers
Danger pattern: Cold weather, fresh snow not bonded with wind
Danger pattern: Rime-covered slopes

Risk assessment
Avalanche danger is in the high mountains above 1800 m CONSIDERABLE, level 3, lower down MODERATE, level 2. The snowpack is less stable mainly on steep slopes, where a bonded slab avalanche can be triggered by a small load. This threat is particularly present where new snow wind slabs have formed on a thin layer of graupel or rime. From today until Wednesday, 30-50 cm of snow will fall above 1700 m in the Julian Alps, elsewhere 10-30 cm. The new snow will be unstable mainly where it falls on graupel or rime. The danger level will remain unchanged.

Snow conditions
During abundant snowfall until Saturday morning, 50-100 cm of snow accumulated in the mountains of western and northern Slovenia above 1300 m, the most above 1600 m in the Western and Southern Julian Alps. During snowfall, a strong southwesterly wind blew, mainly building extensive slabs on northern and northeastern lee slopes. After the passage of the cold front on Friday late afternoon, the wind speed halved, and over the weekend only a moderate southwesterly wind blew. In showers and thunderstorms during the passage of the cold front on Friday late afternoon and Saturday night, graupel or rime fell in places. On Saturday and Sunday, it was mostly cloudy in the west with occasional short-term precipitation; up to 10 cm of snow fell in places. In the east, there was more sun and less precipitation. The snow from the last deterioration has bonded well to the base, but in places the great additional weight of wind-blown snow overloaded old weak layers in the snowpack, so dry bonded slab avalanches spontaneously released mainly from below ridges already during snowfall. The snowpack is slowly transforming and settling. Below about 2000 m, the snow from the last snowfall is already fairly well bonded and connected to the underlying layers. There, an avalanche can be triggered by a small load mainly on steeper slopes. Snow is moist below about 1400 m. Higher up, the snow remained dry and light except on the most sun-exposed slopes, where the snowpack surface has already melted. On Sunday night to Monday, a strengthened southwesterly wind began blowing in the high mountains, transporting dry snow and building small slabs; in places, slabs formed on a thin layer of graupel or rime, so an avalanche can be triggered there by a small load.

Forecast weather development
Today it will gradually cloud over from the west, in the afternoon light precipitation may already be possible in the Julian Alps. It will snow above 1400 m, possibly lower in the north. A moderate southwesterly wind will blow. The zero isotherm will be at about 1500 m, at 2000 m around -3 °C. Tomorrow it will be cloudy and foggy, above 1700 m it will snow all the time, lower it may rain. The zero isotherm will be at about 1700 m, at 2000 m around -1 °C. Precipitation will spread to the east in the afternoon. A weak to moderate southwesterly wind will blow.

Trend in snow conditions
Until Wednesday morning, 30-50 cm of snow will fall in the Julian Alps above 1600 m. Elsewhere, less new snow - 10 to 30 cm. The new snow will presumably bond well to the snow base, except where there is now graupel or rime on top of the snowpack. Areas of wind slab formed in recent days also remain less stable.

Next issue: Thursday, 29.2.2024

Source: ARSO