Temperatures low, precipitation, snow in the mountains
After a particularly rainy August (including first snowfall down to nearly 2000m on 4 August) a warm September followed.
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| Very early and short-lived winter joys on Stubai Glacier, 5 August (photo: 05.08.2020) |
Starting on 22 September, it turned wet again. On 26.09 a massive onset of winter occurred, with snowfall down to low altitudes.
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| Lots of snow in many parts of Tirol for this early in the season |
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| 70 cm of fresh snow at Innsbruck Refuge in the Stubai Alps (photo: 26.09.2020) |
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| Simply too cold for this juncture of the season. Rettenbachtal (photo 27.09.2020) |
Due to a stormy foehn phase bringing rainfall up to high altitudes on 2-3 October, most of the snow on the ground melted quickly.
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| The ellipses mark the precipitation and stormy southerly air current. In the rectangle is the heavy snowfall with dropping temperatures on 25-26.09.2020 |
It filled the brooks to the tipping point in some valleys, e.g. Gschnitzbach in Wipp Valley, where the flooding record of the century was nearly reached.
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| Water level of Gschnitzbach © hydro online |
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| Gschnitzbach (photo: 03.10.2020) |
The first two weeks of October were cool and variable with several rounds of fresh snow, some of which fell down to low altitudes. There were also strong winds blowing in the mountains.
The instable weather often led to deep winter conditions in high alpine regions, which of course pleased the glacier ski areas enormously. There are already good skiing conditions there.
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| Skiing operations of Stubai Glacier (photo: 08.10.2020) |
Backcountry ski tourers also got a first run for their money after heavy snowfall on 26.09. Our observer Lukas Ruetz researched this bout of unusual snowfall and backcountry skiing in autumn: Worth reading!
On 12.10 we received a report from our observer Thomas Mariacher about a possible backcountry tour (for a short time) up the Figerhorn in East Tirol.
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| Ski tour with only 20 cm of snow, thanks to the grassy ground beneath it: Figerhorn (photo: 12.10.2020) |
Regional avalanche danger in autumn. First avalanche victim of the season.
While we were writing this blog we received the news of the first avalanche victim of the season. A backcountry skier on the Grossvenediger who had been missing since Saturday 10.10 was found dead on 13.10. Just below the summit he was swept off by a breaking slab and plummeted over rocky terrain.
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| Grosser Geiger towards Grossvenediger. The arrow shows the approximate area where someone was swept away by a slab avalanche on 10.10. (photo: 09.10.2020) |
A photo on tirol.orf.at shows a fracture below the rocky flank. This must have been a secondary fracture due to the additional weight of the snow masses unleashed. In the secondary fracture you can see the glacier ice peeking through, an indication of a weak layer deeper down inside the snowpack. We don’t yet have reliable information about the background conditions of the avalanche. Signs point to a primary fracture below the summit stemming from a weak layer as the cause. (Initial information points to a 75-cm fracture.) This coincides with the avalanche below the Königspitze in South Tirol on 27.09.2020, where two mountaineers were caught. Details can be found in the blog of our South Tirolean colleagues. What is conspicuous is the moist snowpack surface prior to the release and the huge drop in temperature, with snowfall on 26.09. We assume that as a result of this, a persistent weak layer formed very swiftly in accordance with Danger Pattern no. 4 (cold on warm). Both avalanches occurred at nearly the same altitude. The accident area faces southwest, is at about 3600 m.
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| Numerous glide-snow slides in Ausserfern on 27.09.2020 |
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| Arrows mark fracture spots of glide-snow slides above St. Veit in Defereggen (photo: Vitus Monitzer, 12.10.2020) |
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| Arrows show the loose-snow slides below the Grossglockner due to solar radiation. © foto-webcam.eu |
Afterword: As soon as we receive details about the snowpack layering in high alpine regions, as well as information about the avalanche accident, we will publish a new blog.
