2011-12-13T07:30:00+01:00 Patrick Nairz 2011-12-13+01:00 https://lawine.tirol.gv.at/data/fotos/wind_1.JPG With increasingly strong winds, new, trigger sensitive snowdrift masses will accumulate. The next update will be published at latest on Friday, 16 December 2011. Caution urged on steep, shady slopes above 2600 m and in fresh snowdrift Weather in general: Tirol lies at the southern edge of a powerful low pressure zone with its center over the British Isles, in the path of a strong westerly to southwesterly air current. Disturbances arise and traverse the land repeatedly. Mountain weather today: high altitude, partially dense cloudbanks bearing diffuse light will cross the skies today, although the peaks will remain cloud-free. It will be very windy in some places and turn noticeably milder. The freezing level will be at just over 2000 m and rising. Temperature at 2000 m: plus 1 degree; at 3000 m: minus 4 degrees. To begin with, moderate to brisk southwesterly winds, escalating to strong velocity and even storm strength over the course of the day. Trend: variable conditions and wind will continue. Over the last 24 hours there has been generally 5 to 10 cm of snowfall in Tirol, along the Main Alpine Ridge as much as 20 cm. The snow was transported, particularly at higher altitudes. Due to the wind shifting from northerly to southwesterly, freshly formed snowdrift accumulations occur with increasing frequency on south to northeast to north facing slopes. The old snowpack from snowfall in September and October must be treated highly critically: on high altitude, shady slopes, and on glaciers also on west and east facing slopes, this old snow has been transformed into loosely packed depth hoar. The snow which has been deposited on top of it since early December is very poorly bonded to it, thus enabling avalanches to be easily triggered. Elsewhere, the snow from last week has settled well and is now quite stable. At lower altitudes, it has already melted, due to the mild temperatures. In the regions along the Main Alpine Ridge, considerable avalanche danger prevails above approximately 2600 m, a direct result of the recently formed snowdrift accumulations on steep, shady slopes. Slab avalanches can be triggered even by the additional loading of one single backcountry skier or freerider. This was amply demonstrated by a series of avalanches in recent days. With ascending altitude, the frequency of danger zones escalates, particularly on glaciers and increasingly often also on very steep, west and east facing terrain. Also in Tirol’s remaining regions, great care must be exercised towards freshly formed snowdrift accumulations, especially when immediately adjacent to ridge lines. Our tip: avoid recently formed snowdrift masses in very steep terrain. In Tirol’s western regions with lots of snow, snowslides on steep, grassy slopes are also possible.