Snow conditions 24. 3. 2025

General danger level - Monday, 24. 3. 2025
Danger is level 3 on the European five-level scale - CONSIDERABLE.
Main problem: weak layers, wind slab, wet snow
Danger pattern: Cooling after warm weather / warming after cold
Danger pattern: Rain

Risk assessment
Danger is CONSIDERABLE, level 3 in the high mountains. In the high mountains, a lot of new snow has fallen in places. In sunny weather, new snow on sun-exposed slopes will quickly crust up to the highest peaks, during which small avalanches of wet non-cohesive snow will release. Sun-exposed slopes in this part of the year also include east and west slopes! On shady slopes, new snow has buried old weak layers, which can fail under high load and cause the release of a dry cohesive slab avalanche. The snowpack is unstable also in wind slabs built by the south wind. The strengthening northeast wind will build new wind slabs on Wednesday and Thursday, where a dry cohesive slab avalanche can be triggered even with small load.

Snow conditions
From Friday to Monday, there were precipitations in the mountains. The snow line fluctuated between 1600 and 2000 m, during heavy precipitations on Saturday midday and with showers today, Monday early morning, it dropped slightly below 1600 m. Above 2000 m in the Western and Southern Julian Alps, around 50-70 cm of new snow fell. Elsewhere in the Julian Alps, less new snow, up to 40 cm, in the Karawanks and Kamnik-Savinja Alps up to 30 cm. It snowed with strong south wind. Snow fell on sun-exposed slopes onto a hard base, crust. On shady slopes onto a soft base, under which there were already weak layers of faceted grains before the precipitations. There, shallow and deep dry cohesive slab avalanches released spontaneously during snowfall. Weak layers remain buried under new snow and can represent a weak point under high load.

Forecast weather development
Today it clears after morning precipitations. During the day, variable high cloudiness will form, summits will occasionally be in clouds. In the afternoon, individual short showers possible. During the day, weak wind will blow again, moderate in the high mountains from southwest. Temperature at 1500 m around 4, at 2000 m around 0 °C. Tomorrow initially partly clear. During the day, increasing variable cloudiness, summits often in clouds. From midday, local showers will start, more frequent in the afternoon, possibly with thunder. Weak southwest wind blowing. Temperature at 1500 m around 4, at 2500 m around 0 °C. On Wednesday mostly cloudy with occasional light precipitations. Moderate northeast wind will start blowing, strengthening in the night to Thursday. On Thursday dry but windy, temperature similar to Wednesday. Cloudiness forecast still very uncertain.

Tendency of snow conditions
Today, Monday, and tomorrow, Tuesday, new snow on sun-exposed slopes will settle and transform quickly. Overnight, a crust will form on the surface. Even in the high mountains, small avalanches of wet non-cohesive snow are spontaneously releasing on sun-exposed slopes. There will be more of these avalanches during the day today, the cycle will repeat tomorrow, Tuesday. On Wednesday there will be fewer, as there will be less sun and northeast wind will start blowing. Among sun-exposed slopes in this part of the year, besides south, also east and west slopes. On shady slopes, snow will slowly consolidate but remain light. Buried weak layers will persist at least a few more days. The northeast wind on Wednesday and more so on Thursday will transport non-cohesive snow from shady slopes and deposit it on sun-exposed lee slopes. There, the wind slab will probably not bond well with the base, so the probability of triggering a dry cohesive slab avalanche will increase.

Next issue: Thursday, 27. 3. 2025

Source: ARSO