Snow conditions 29. 4. 2024

General danger level - Monday, 29. 4. 2024
Danger is level 3 on the European five-level scale - CONSIDERABLE.
Main problem: wet snow
Danger pattern: Cooling after warm weather / warming after frost

Risk assessment
Avalanche danger is CONSIDERABLE, level 3. In the morning, the snow cover on top is frozen and somewhat more stable, during the day however it softens and moistens. Wet snow avalanches can release spontaneously or while skiing.

Snow conditions
During the spring thaw, the snow cover has been rapidly transforming and settling higher up every day. In many places, the surface layer became so unstable by midday that even larger wet snow avalanches released spontaneously. The night to Monday was clear, dry and calm, so a crust formed on the snow cover surface even in mid-mountains. The main threat currently is spontaneous release of wet snow avalanches due to daytime thaw. These avalanches can release even on aspects of the highest summits, more on steep shady slopes. The surface slab of heavily moistened upper layers can also be triggered while skiing.

Expected weather development
Monday and Tuesday sunny and warm, zero isotherm at approx. 3200 m. Monday weak southerly wind, Tuesday easterly wind. Wednesday morning clouding from the west, initially weak southerly, afternoon southeasterly moderate in high mountains. Slightly cooler, zero isotherm at 2700 m. Afternoon light rain starts, light snow above 2500 m. Up to Thursday morning max. 10 cm snow. Thursday morning precipitation intensifies, rain all day, possibly thunderstorms. Snow above 2500 m. Precipitation amount forecast still quite uncertain, in Western and Southern Julian Alps 10-50 cm snow possible, less elsewhere.

Trend in snow conditions
Monday and Tuesday similar snow conditions. After night-time freezing, the snow cover surface softens in the morning and moistens further during the day. Thereby it destabilises and can slide as a wet snow slab spontaneously or under skier influence. Release more likely where snow is wetter (shady slopes) and where it slides more easily on hard base (steep terrain). Slight cooling and cloudy weather on Wednesday will reduce the probability of such avalanches in high mountains, new snowfall mainly on Thursday daytime will cause increased avalanche danger especially near high mountain ridges. There, wind-loaded new snow deposits will form in leeward positions where slab avalanches can be triggered.

Next issue: Thursday, 2. 5. 2024

Source: ARSO