2016-12-23T09:00:00+01:00 Patrick Nairz 2016-12-23+01:00 https://lawine.tirol.gv.at/data/fotos/2015_bewoelkte_Gipfel_kein_Schnee.jpg https://lawine.tirol.gv.at/rest/bulletin/2016-12-23_090000/pdf/en Freshly formed snowdrifts will persist as the major problem. Daily bulletins will start as soon as the first heavy snowfall arrives. Caution: small, fresh snowdrifts. Daily bulletins not beginning yet. DP6 DP1 Alpine Weather Forecast (ZAMG-Weather Service Innsbruck) Weather. The high pressure front over western and central Europe weakened on 22 December, will regain strength during the daytime on 23 December. The result is: renewed dry weather with lots of sunshine. As of Christmas Eve, the weather scenario will be shaken up somewhat, but heavy snowfall is still not in sight. Snow Layering For this juncture of the season there continues to be too little snow. Sunny slopes are bare up to high altitudes. Backcountry winter sports are severely reduced, realistic only in high alpine terrain. This is because the snowpack transformed massively to faceted crystals during the extensive period of fine weather, wherever it didn’t melt entirely. The crusts which to start with were capable of bearing loads became ever thinner. The upshot: below about 2800m, one breaks through the snow down to the ground. The snowpack structure is characterized by faceted crystals, depth hoar and surface hoar and generally thin crusts. As soon as drifts are deposited on top of this, the overall mass becomes highly prone to triggering. This is evident through many shooting cracks on the surface and settling noises of the snowpack (whumpf!). The frequency of crusts embedded inside the snowpack and the impact of wind tend to increase with ascending altitude. On high-altitude, sunny and steep slopes there are some melt-freeze crusts capable of bearing loads. Avalanche Danger Potential avalanche hazards are currently limited to small-sized yet highly trigger-sensitive snowdrift accumulations, to be specific, the drifts which formed around 19 December. Over the holidays the number of such danger zones will increase, due to some snowfall and strong winds. Avalanche prone locations can be found wherever the old snow cover was minimally impacted by recent foehn winds. This applies especially to shady terrain above about 2200m. The advantage: with experience, the freshly formed drifts can be easily recognized and circumvented. In addition, above approximately 2800m there is a potential old snow problem. Based on observations and reports, there are few danger zones: only extremely steep, particularly shady, transitions from shallow to deep snow can trigger as a result of large additional loading. Caution: these also include zones where the snowpack surface is hardened.