The week was characterised by opposing snow and weather conditions. At first the days were clear with below average temperatures, but from mid-week onwards an extensive low pressure area from the north brought heavy snowfall and strong winds.
The snow quality remained excellent until January the 12th, with a surface layer of loose snow that was very nice to ski on. Strong North-western winds spoiled the snow quality for a couple of days, then heavy snowfall brought back excellent snow conditions along all the elevations.
SNOWPACK STABILITY AND AVALANCHE OBSERVATIONS
Above the treeline, with strong winds and snowfall, unstable, generally medium and locally even large sizes, snow-drift accumulations formed. Along open slopes, the wind slabs are recorded even below the treeline. Above the treeline, mainly on aspects ranging from South-East to North-East, the slabs stand on persistent weak layers, the single person or the release of the new wind slabs could trigger avalanches which could reach bigger sizes. During the night and the morning natural avalanche activity could still be possible. Avalanche activity increased with increasing winds and snowfall and peaked between January the 14th and January the 15th. Many natural and triggered avalanches (soft and wind slabs) were recorded along all exposures and elevations. Most of the avalanches were of size 2; on the larger slopes or those with greater snow-drift accumulations they also reached large sizes.
Above the treeline the snow surface is strongly wind affected; along windward slopes the snowcover thickness is lower and is characterized by a more compact snow layers; along the leeward slopes, snow-drift accumulations formed. Above the treeline, mainly on slopes ranging from South-East to North-East, the persistent weak layers recorded within the snowcover are closer to the snow surface. Below the treeline, on the snow surface soft slabs and a loose snow layer (30-40 cm) alternate each other’s. Along Northern slopes, the higher the altitude, the more the old snowpack is made up by persistent weak layers alternating with melt-freeze crusts.
From January the 9th until midday on January the 12th the weather was sunny with below average air temperatures. Snowfall began on January the 13th and continued until Friday the 15th, bringing about 45 cm of fresh snow to Livigno village. The snowfalls were accompanied by moderate to strong North-western winds.
2021_01_15 Manual snow profile, near the Polvere piste