Snow Conditions 28.12.2017

General danger level - Thursday, 28. 12. 2017

Danger is level 4 on the European five-level scale - HIGH.

Main problem: new snow, wind-blown snow

Danger pattern: Cooling after warm weather / warming after frost



Risk assessment

Avalanche danger is currently above about 1400 m above sea level HIGH, level 4, lower down CONSIDERABLE, level 2. During snowfall in the last 48 hours, 20 to about 100 cm of snow fell in the mountains, the most in the Julian Alps and western Karawanks, the least on Pohorje and in the extreme east of the Karawanks. The snow line was initially also up to about 1300 m above sea level, in places with heavy precipitation significantly lower. At the end of precipitation it dropped below 1000 m. A strengthened southwesterly wind blew, creating drifts and slabs. In many places it snowed on a crusty or even hard base, so there are weak layers in the snowpack.



Snow conditions

The snowpack is soft and loose, especially above about 1500 m poorly bonded. There are many drifts and slabs, wind-exposed locations are heavily scoured, sometimes to the old base. Lower down, snow melted and became soaked in the rain, then it snowed on such a base, so the new snow bonded well with it.



Forecast weather development

Today cloudy with occasional precipitation, more of it in eastern and southern regions. The snow line will lower and in the afternoon and evening it will snow in some lowlands. Approximately 5 to about 20 cm of snow expected in the mountains, this time more in the eastern part of our mountains, especially in the hills of central and southern Slovenia. A wind from northern directions will blow, transporting snow again. The wind will not be as strong as the southwesterly in previous days. Freezing level will drop to about 700 m above sea level. Friday partly clear and dry, wind weakening during the day. Saturday mostly dry weather, gradually warming up again in the heights. Freezing level will rise to about 2000 m above sea level by Saturday evening. Sunday also mostly dry, freezing level mostly above our highest peaks. Already on Saturday southwesterly wind will strengthen, blowing also on Sunday. Renewed precipitation expected on Monday, when snow line initially between about 900 and 1400 m above sea level.



Tendency of snow conditions

The snowpack will settle only slowly today and tomorrow, remaining mostly loose and soft. Northerly and northeasterly wind will create new drifts on south sides of ridges and saddles. Both today and tomorrow spontaneous release of avalanches of dry, unbonded snow possible especially from steep slopes. On Saturday southwesterly will transport snow again, which due to warming will start to settle and transform somewhat faster especially in mid-mountains. The process will be even more pronounced on Sunday. Due to warming the snowpack will initially become somewhat unstable especially on Sunday. Crust will form on the surface, also due to wind. Especially steeper slopes and places with wind-blown snow will be dangerous. Avalanche danger will only SLOWLY DECREASE. With renewed precipitation on Monday danger will increase again.



Next issue: Monday, 1. 1. 2018



Source: ARSO