End of 2018 / Beginning of 2019: Stormy and Snowy
The start of the new year is storm-ridden (windspeeds of 180 km/hr in the southern Ötztal Alps) throughout Tirol, and there is lots of fresh snow in many places. In coming days the ZAMG weather service forecasts additional, at times very heavy snowfall, with the focal point east of Wipp Valley and northern East Tirol.
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| Illustrative of last week: the Hahnenkamm-Ehrenbachhöhe weather station in the Kitzbühel Alps. Weather deterioration starting on 30.12 amidst precipitation and wind. |
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| Southern East Tirol ended up with practically no snow. |
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| Snow plumes showcased wide-ranging snow transport throughout the land, as here in the northern Stubai Alps. (photo: 01.01.2019) |
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| Matrei Tauernhaus in the Venediger range during heavy snowfall and stormy winds. The stark gradients of snow depths towards the south are interesting. While here at the southern portal of the Felbertauern there was 40 cm of fresh snow on 01.01/02.01, in Matrei in East Tirol there was barely 5 cm. (photo: 02.01.2019) |
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| Extremely interesting, quite seldom: the snow balls formed by the storm-strength winds in the free spaces in Kals (also behind the church). (photo: 31.12.2018) |
Snowpack development
A precise-as-possible depiction of snowpack layering is crucial before intensive precipitation. Currently the problem areas inside the snowpack are concentrated on the layers nearest to the upper surface. More deeply embedded graupel can also play an important role.
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| Yesterday on 02.01 during the snowfall: a thick layer of graupel was deposited in some places; this is now a potential weak layer for coming rounds of snowfall. Graupel was observed throughout Tirol. Kaiserbachtal (photo: 02.01.2019) |
Furthermore, covered powder snow is a temporary weak layer for the drifted masses which have been deposited on top of it. This can frequently be observed during intensive snowfall when temperatures are low.
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| Superficial slab on a gliding snowpack, recognizable by the glide cracks. Ausserfern (photo: 29.12.2018) |
The old-snow problem in the central sections of the snowpack referred to repeatedly in the most recent blogs seems in the interim to have shrunk to relatively narrow aspects and altitude bands. It is focused on the inneralpine regions, such as central East Tirol, where we assume potential problem zones on south-facing slopes between about 2400 and 2600 m and on north-facing slopes between about 2200 and 2600 m (in some places up to 2800 m). These zones are not usually cohesively connected over widespread areas.
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| A backcountry skier was ascending when an avalanche was triggered. The person remained unhurt. Gaishörndl, Villgratental. Limited-terrain old-snow problem (photo: 01.01.2019) |
The snowpack’s proneness to triggering has diminished in these areas due to the temperature development, including warm phases. Nevertheless, we still have to expect these layers to fracture, at very least in the regions where precipitation has been heaviest. Deep persistent weak layers which formed on north-facing slopes on glaciers in autumn, can in all likelihood now be triggered only in highly unusual cases, i.e. through the additional loading of an avalanche which forms at altitudes above them in those regions where snowfall has been heaviest.
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| Typical of recent days: highly fluctuating temperatures. This was particularly striking in the northern regions, where there was drizzling rain as far up as 2200 m for a brief interim. |
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| The snowpack over the course of this last week was moistened on the surface: unbonded-snow avalanches on 27.12.2018 near the Pleisenspitze in the Karwendel. All in all, it had a positive impact on snowpack stability. (photo: 28.12.2018) |
Outlook
The ZAMG weather forecasting institute has issued a heavy snowfall warning for the morning of 04.01 until 07.01.2019, with more than 100 cm of fresh snow expected from region to region.
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| Eastern regions got the brunt of the snowfall. |
Avalanche danger is increasing to high in the indicated regions. We expect increasingly frequent naturally triggered avalanches, particularly on leeward, very steep slopes adjacent to ridgelines and below rocky zones. The avalanches can easily reach
large size (sizes 3-5) and even
very large size (sizes 4-5).
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| Detailed forecast for the Venediger range: ongoing snowfall and continuing strong-velocity winds. |
Already yesterday (02.01) and again today (03.01) several large-sized avalanches were triggered. Such releases occurred frequently in the regions along the eastern sector of the Main Alpine Ridge.
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| Naturally triggered avalanche in the Zillergrund. Further avalanches can be expected during the coming days in these regions, particularly where snowfall is heaviest. (photo: 03.01.2019) |
One thing is certain: during the next few days, massive traffic jams are on the agenda.
In the end, we appeal to all backcountry skiers and freeriders: whoever is en route in outlying terrain needs profound knowledge of avalanche risks and should behave highly defensively. We advise the inexperienced to remain on the secured and marked ski runs over the coming days.
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| From region to region, there is still a lot more snowfall on the way...Lampsenspitze. Northern Stubai Alps (photo: 03.01.2019) |
