Avalanche Bulletin Thursday, 12.12.2013, at 07:30
Generally favourable situation
The avalanche situation in Tirol’s backcountry touring regions remains favourable in general: the hazards below about 2200 m are low far and wide, above that altitude they are moderate. More than anything else the snowdrift accumulations from last weekend are the major peril. Avalanche prone locations are to be found mainly on extremely steep, shady slopes, the transition areas from deep to shallow snow should also be cautiously evaluated.
Snow depths in most outlying terrain are somewhat below average. Particularly at low and intermediate altitudes the mild weather has diminished the snowpack further. Snowdrift masses from the last bout of snowfall and storm wind have frequently been deposited atop a layer of faceted, loosely packed snow crystals. However, since as a result of the heightened temperatures these are no longer as brittle, avalanches are likely to be released only by large additional loading.
Alpine Weather Forecast (ZAMG-Weather Service Innsbruck)
Weather in general: The powerful wintery high pressure zone covering much of the European continent is weakening somewhat, but still dominates the weather throughout Tirol. Mountain weather today: another day of sunshine, the thin veil of cloud will not impede it. Light winds and very mild for December, the zero-degree level again at about 2600m. Temperature at 2000m: +4 degrees, at 3000m -2 degrees. Light easterly to northeasterly winds.
Short Term Development
Favourable avalanche situation will continue.
[Author: Rudi Mair]
[Translated by Jeffrey McCabe]
Current danger pattern(s)
Experience has shown that even over the course of highly varied winters, nearly identical potential-avalanche scenarios repeatedly arise as recurring danger patterns and are responsible for the greater part of avalanche accidents. An analysis of these patterns was published in the practical handbook "Avalanche - Recognizing the 10 Decisive Danger Patterns" by Rudi Mair and Patrick Nairz in November 2010.
Danger pattern (dp) 7 - snow-poor zones in snow-rich surrounding
In winters with lots of snow, far fewer avalanches are generally unleashed than in winters with little snowfall, since the snow layering is generally far better in snow-rich winters. Nevertheless, it can regularly be observed, also in winters with lots of snow, that due to prevailing weather conditions, slopes exposed to wind have relatively little snow. In such areas, the snow layering is less favourable. And thus, it is far more likely that avalanches get triggered by backcountry skiers and snowboarders in those zones. You can observe this phenomenon also during a winter with an average snow-cover, if there are snow-poor zones in a snow-rich surrounding. Problems will mostly occur on convex slopes or in the vicinity of ridges.