A new round of fresh snow was unloaded on Tirol, most in the northern, eastern and furthermost western regions, as well as in the eastern Zillertal Alps. Frequently between 30 and 50 cm of fresh snow was registered, the prize was won by the Seegrube measurement station above Innsbruck (once again): just under 100 cm.
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| Fresh snow started Sunday evening, 10.02, amid strong winds which have now tapered off. “Am Adamsberg” weather station in Paznauntal |
Accompanied by low temperatures and strong winds, wide-ranging snowdrifts accumulated, some of them trigger-sensitive.
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| Snowfall in the Lienz Dolomites (photo: 12.02.2019) |
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| Unpleasant: strong winds transporting the snow, en route in the northern Stubai Alps. (photo: 12.02.2019) |
The fresh snowdrift accumulations are easiest to trigger in very steep, untracked, shady terrain and in general in very steep terrain adjacent to ridgelines. Weak layers for slab avalanches are the surface hoar on shady slopes below the timberline and, more frequently, the older powder snow (“burled powder”). In addition, the cold powder covered by the drifts could also serve as a weak layer, particularly in sunny terrain where before 10.02 a melt-freeze crust often formed. Caution is urged towards the upper-level faceted weak layers at 2300-2600 m referred to in the last blog. In the central and southern parts of East Tirol, a latent old-snow problem still threatens in ground-level layers, increasingly so on north-facing slopes.
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| Particularly on shady slopes at low and intermediate altitudes, surface hoar was observed last week. Obernbergtal (photo: 05.02.2019) |
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| “Burled powder” as potential (but not highly delicate) weak layer. Kitzbühel Alps (photo: 07.02.2019) |
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| On sunny slopes, the snowpack became moist last week. Kitzbühel Alps (photo: 07.02.2019) |
Starting today, 13.02, a long period of fine weather and brilliant sunshine is in the offing, with continually rising temperatures. Impulses supplied by warmth and solar radiation will unleash numerous loose-snow avalanches in extremely steep, sunny terrain today, 13.02. In addition, isolated naturally triggered releases of the fresh snowdrifts cannot be ruled out in sunny ridgeline terrain. On steep slopes where the ground is smooth, heed the risks of gliding snow masses; and glide-snow avalanches on steep, grass-covered slopes. Also rooftop snowslides have been increasingly observed during the last few days.
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| Loose-snow avalanches in rocky terrain. Photo of Mieming range on 04.02.2019, a similar syndrome expected today, 13.02. |
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| Ridgeline slab in foreground, gliding snow masses in background. In the interim, deep snowdrifts have accumulated near ridgelines. Kitzbühel Alps (photo: 07.02.2019) |
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| Slab in Villgratental, fractured from a deep layer. (photo: 07.02.2019) |
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| Slab in Defereggental. A deep weak layer was the primary cause. (photo: 12.02.2019) |
We recommend a high degree of restraint today. Freshly generated drifts in very steep terrain should be circumvented wherever possible.
The positive side: we expect the snowpack to stabilize rapidly wherever there is not a latent old-snow problem. In addition, springtime conditions will soon make their entrance.
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A powder dream come true in many parts of Tirol. Defereggental (photo: 12.02.2019)
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