Current situation
Above average snow depths in far-reaching parts of Tirol for this juncture of the season.
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| Snow-depth map for Tirol, South Tirol and (not shown) Trentino. Decreasing depth curve towards the south. |
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| Snow depths diminish steadily as the old snowpack consolidates. It is cold, winds are light. The extremely low surface temperature of the snowpack is a decisive factor for coming development. |
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| Bitter cold in far-reaching parts of Tirol. |
Low temperatures reinforce the metamorphosing of the snowpack surface. That means that the snow crystals become unbonded, typically forming faceted and decomposed snow crystals, also surface hoar. In addition, there is cloud cover resembling high fog in many parts of Tirol in which very light, fluffy powder snow - so-called ‘wild snow’ - is lodged.
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| On the snowpack surface there are loose, very cold snow crystals in far-reaching parts of Tirol. (photo: 21.01.2019) |
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| The “Nigg Effect” in ridgeline terrain in the Arlberg region. (photo: 21.01.2019) |
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| Huge surface hoar crystals in Gschnitztal just above a brook. (photo: 24.01.2019) |
Review
Regions of Tirol where snowfall was heavy have become a winter wonderland.
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| Glungezer in the Tux Alpen (photo: 18.01.2019) |
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| Deep snow blankets alm huts in the lowlands. (photo: 19.01.2019) |
In addition, mostly low avalanche danger prevailed over the last few days in those regions where snowfall was heaviest. Many winter sports fans took advantage of favourable conditions to undertake steep ascents and descents.
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| Descent from Hochnissl (photo: 22.01.2019) |
There was moderate danger at low and intermediate altitudes where snow has been heaviest because of the gliding-snow problem. Glide-snow avalanches did not release as frequently as during and just after the intensive snowfall, yet the risk of isolated, even very large glide-snow avalanches persisted.
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| Glide cracks on the Saile. View to the Inn Valley (photo: 20.01.2019) |
Least favourable of all were conditions in the southern and central parts of East Tirol, where particularly on W/N/E facing slopes between 1800 and 2500 m an old-snow problem prevailed. The trigger sensitivity of the now older snowdrift accumulations has diminished due to low temperatures, but the danger has not passed.
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| Southern East Tirol: little snow, trigger-sensitive snowpack (photo: 20.01.2019) |
Last week was marked by intensive snowpack analysis and stability tests. With the exception of the already mentioned old-snow problem in East Tirol, which was less risky in the regions of the central Stubai Alps, our stability tests showed a thoroughly favorable development inside the old snowpack.
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| Snowpack examinations conducted with the Alpine Police in the Zillertal Alps (photo: 22.01.2019) |
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| Snowpack examinations in the Venediger group with Peter Fuetsch, one of our observers (photo: 19.01.2019) |
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| Snow profile from rear Gschnitztal on 24.01.2019: persistent deep weak layers have bonded well with each other. |
The development in the uppermost layers of the snowpack is rather different, however, as described above in the “Current situation” section. Furthermore, on steep south-facing slopes we observe in the upper layers at altitudes of 2200-2400 m an increasing expansive metamorphism beneath the thin melt-freeze crust (
danger pattern 4 - cold on warm).
Outlook
The weather is about to become more turbulent. Tomorrow (25.01) winds will intensify, particularly in the south. In addition, starting on Saturday (26.01.2019) snowfall is anticipated in wide-ranging parts of Tirol.
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| Schneefall und Wind kündigen sich für die kommenden Tage an. |
Danger pattern 5 “Snowfall after a longer period of cold” appears to be approaching rapidly. This is infamous as an accident ridden danger pattern: atop a wide-ranging loosely bonded, cold snowpack surface, snowdrifts are deposited.
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| In most parts of Tirol, there are wide-ranging snowpack surfaces of cold snow. |
These snowdrift accumulations can be triggered very easily by minimum additional loading. Wherever there is snowfall, increasingly frequent (generally small-to-medium sized) naturally triggered avalanches can be expected. Avalanche danger will rise at least to considerable, also to high in those regions where snowfall is heavy. The major risk will then be borne by winter sports participants, who will in all likelihood trigger avalanches themselves.
For that reason, we advise avoiding freshly generated snowdrift accumulations without exception. Once again, backcountry skiing and freeriding tours demand much experience in assessing dangers on-site and a high degree of restraint. The situation in much-used freeriding terrain is measurably better, since the loose and even quality of the snowpack surface no longer exists.
