Snow conditions 16.3.2018

General danger level - Friday, 16 March 2018

Danger is level 3 on the European five-level scale - CONSIDERABLE.

Main problem: new snow, wet snow, weak layers

Danger pattern: cooling after warm weather / warming after frost



Risk assessment

Avalanche danger is currently CONSIDERABLE, level 3. This mainly applies to the Julian Alps and western Karawanks, where more snow fell overnight. Elsewhere in our mountains, the danger is MODERATE, level 2. Steep slopes and areas with wind-packed snow are particularly hazardous. There, even a minor load on the snowpack can trigger an avalanche. In possible sunny weather, the danger will increase slightly midday and in the afternoon. From steep grassy slopes below around 1500 m, individual ground avalanches may release mainly midday and in the afternoon, also in lower areas where the somewhat thinner snowpack is saturated to the ground due to warming and rain.



Snow conditions

Overnight, 10 to around 30 cm of snow fell in the Julian Alps and western Karawanks area, much of which was redistributed by the southwest wind. Elsewhere in our mountains, precipitation was much less, with around 5 cm of new snow. The snow line was between 900 and 1200 m in the west, slightly higher to the east. In the high mountains above around 1500 m, the new snow has not bonded well to the mostly crusted surface. Lower down where it rained, the rain further saturated the snowpack. Thus below around 1500 m, the snowpack is crusty, wet and softened; higher up, it is either old, mostly crusted base, with old snow somewhat soft only in shady spots. In the western part of our mountains, new snow is soft and light, and scoured to the old base in wind-exposed spots. There are many drifts.



Forecast weather evolution

This morning, precipitation will mostly cease, with clouds breaking in the afternoon. It will remain cloudier in the Julian Alps area, where an early afternoon shower is possible. In the morning, the southwest wind will veer to northwest. Freezing level at 1700-1800 m. Overnight, clouding from the south; tomorrow morning, precipitation will spread from the south over all Slovenia. Initial snow line between 700 and 900 m, slowly lowering during the day; by evening, snow possible to lowlands in places. Cooling. Winds from easterly directions. Precipitation weakening evening and night to Sunday. Sunday cloudy and foggy, occasional light snow in places. Light snow mostly ending in the afternoon. Light winds of variable direction. Monday mostly cloudy and mostly dry. Cold, winds from southeast to northeast.



Trend in snow conditions

Today, snowpack below around 1600 m will continue settling and melting; higher up, with negative temperatures, it will transform only slowly. Wind will transport snow into drifts. Tomorrow's new snowfall and cooling will alter avalanche conditions. Above around 900 m, snow only. In most of our mountains above around 900 m, 20-30 cm snow will fall, possibly more in places. Above around 1200 m, snow will be dry, leaving a weak layer beneath the new snow along which it may slide in coming days. Being dry, wind will transport it and form new drifts. Lower down, snow will initially bond well to the base; upon cooling, the wet base will freeze and become more stable. Avalanche danger will remain CONSIDERABLE, level 3; in lower elevations, old snow will freeze on cooling, with too little new snow to increase sliding risk.



Next bulletin: Monday, 19 March 2018



Source: ARSO