Snow conditions 15. 3. 2023

General avalanche danger level - Friday, 15. 3. 2024
Danger is level 2 on the European five-level scale - MODERATE.
Main problem: windpacked snow, wet snow
Danger pattern: Spring situation

Risk assessment
Avalanche danger is MODERATE, level 2. The snowpack is mostly stable. Stability deteriorates during the day in sunny weather on all pronounced sun-exposed slopes, where a wet snow avalanche can be triggered. In the morning, snow is mostly refrozen, in places in the high mountains, especially on wind-exposed spots, it can also be hard and icy, posing a risk of slipping. In high mountain gullies, snow is still dry and in places windpacked onto a faceted weak layer (depth hoar) - there is a risk of slab avalanche release with additional stress.

Snow conditions
The snowpack transforms rapidly in warm and sunny weather - especially on sun-exposed slopes, where the snow surface has crusted up to the highest peaks. On the most pronounced sun-exposed slopes below 2300 m, the top crust layer has already refrozen thick enough to support the weight of a skier and also a hiker, but it softens during the day, especially in sunny weather. In forest shelter and gullies, refreezing was less intense, so the crust still breaks under a hiker's weight there. In shade in the high mountains, snow is dry in places, but often compacted by wind action. On slopes up to 2000 m elevation, wet non-cohesive snow lurks under the crust. In the morning and forenoon, the snowpack on sun-exposed slopes below around 2000 m is stable, as the hard crust adequately supports the load of skier and hiker without overstressing deeper layers. On sun-exposed slopes above 2300 m, the snowpack has not yet refrozen thick enough, so there remains a risk of cohesive snow slab release due to overstress of windslabs especially near ridges. During the day, on the most pronounced sun-exposed slopes (first on SE slopes, then S, and finally SW), the snow surface can soften to the point of becoming non-cohesive and unstable. At that time and place, a wet snow avalanche can release spontaneously or with additional stress. In high mountain gullies, conditions are still wintery; due to persistent weak layers (depth hoar) in the snowpack, a slab avalanche can release on slopes not the steepest (below approx. 50°) with additional stress. Especially near ridges, snow is wind-scoured to old refrozen base in places, or to ice crust (from rain a week ago) up to 2200 m elevation.

Forecast weather development
Friday will be partly clear with occasional increasing cloudiness. Zero isotherm around 2400 m. Mostly light northerly winds, in mid-mountains temporarily light westerly in the afternoon. Saturday morning cloudy with minor precipitation. Snow line around 1900 m. Up to about 5 cm of snow possible. Afternoon partly clearing, isolated mainly snow showers. Slight cooling, 0°C around 2100 m. Light winds, moderate in places in high mountains from northerly directions. Overnight to Sunday clearing, after sunny morning clouding up in afternoon. Light westerly wind. Temperature conditions similar to Saturday. In the morning, due to clear night, snow will be frozen. Monday mostly cloudy and locally foggy. Especially midday and afternoon local showers, snow line around 1800 m. Mostly northwesterly winds, light to moderate in high mountains, light lower down.

Trend in snow conditions
Saturday's precipitation is not expected to significantly affect snow and avalanche conditions. Temperature fluctuations will favorably influence gradual transformation and crusting of snow. In mid-mountains, especially on sunny aspects, snow will diminish. It will freeze overnight, but soften during the day, depending mainly on cloudiness and of course elevation. Long-term, the snowpack will slowly stabilize, as no significant thaw or rain is forecast for the coming week. Above about 2200 m, transformation (and daily melt and nightly freeze) will be slower, in shady aspects snow will remain dry or frozen.

Next bulletin: Monday, 18. 3. 2024

Source: ARSO