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| Overview of snow depths in Tirol. North of the Inn, there is 20 cm at high altitude over widespread areas. On the Main Alpine Ridge and southwards therefrom, there is 50 cm widespread, in high alpine zones significantly more. |
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| Winter conditions on Leppleskofel in Defereggental. The latest round of precipitation created a cohesive, area-wide snowpack above 1000 m. (Photo: 10.11.2019 |
Fresh snow before the weekend
It started snowing from the south on Monday afternoon. Today, Tuesday, skies remained gray, light snowfall persisted in the north, moderate snowfall on the Main Alpine Ridge and in East Tirol.
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| In southern East Tirol precipitation was the heaviest yet. This will continue to be the region where precipitation is heaviest. |
In the wee hours of Wednesday, 13 November 2019, the precipitation will intensify. The focal point continues to be the Main Alpine Ridge and East Tirol. The amounts of precipitation will vary greatly from region to region, 30-80 cm of fresh snow is anticipated. Most of the precipitation is currently expected in the Zillertal Alps and Lienz Dolomites. Winds will be blowing from the north, in places at strong velocity, in the direction of the Main Alpine Ridge. On Thursday the ZAMG weather center forecasts a dry day accompanied by a foehn syndrome in North Tirol including a mixture of sunshine and clouds. The brisk southerly foehn wind will reach strong to storm-velocity by evening. In East Tirol, the sun will barely be able to compete with the residual clouds resembling high fog.
On Friday more snowfall is expected, thanks to a powerful southern front. In North Tirol away from the Main Alpine Ridge, a storm-strength southerly foehn will be blowing; in southern regions it will be gloomy. Heavy snowfall is expected from the Brenner to East Tirol down into the Lienz basin.
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| The 48-hour forecast of fresh snow in the Europaregion. In the Zillertal Alps and Lienz Dolomites, up to 80 cm of fresh snow is expected from place to place. |
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| A multimodel forecast of fresh snow for one spot in the Lienz Dolomites: high likelihood of 50 cm fresh snow in the next few hours. Further precipitation forecast for Friday and Sunday. |
Avalanche danger, snowpack and on-site backcountry observations
There is currently very little information available from outlying terrain, thus, very little insight of the snowpack layering in the various regions is possible.
As a result of fresh snow and snowdrifts, the danger of avalanches will briefly spike on Wednesday. Avalanches can be triggered by skiers and freeriders from place to place and grow to large size in the regions where snowfall is heaviest. This includes in particular those regions where there was a cohesive, area-wide snowpack prior to the snowfall.
On very steep grass-covered slopes, repeated small-to-medium sized glide snow avalanches were registered during the last few days. As snow depths increase, glide-snow avalanche activity will, too.
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| Frequent glide-snow avalanches are already being observed on steep grass-covered slopes. Their size and frequency will increase over the next few days in the regions where snowfall is heaviest. |
The few snow profiles currently available show the following characteristics: on shady slopes above 2500 m there are mostly melt-freeze encrusted and faceted layers which alternate with each other. On top of those lies the snow from early November. Stability tests show frequent fractures in the layers closest to the upper surface from the latest rounds of precipitation. Fractures tend not to propagate. Nonetheless, the fresh snow which is often loosely packed at high altitudes, and which will soon be covered by deep masses of fresher snow, requires attentiveness. Over the short term, this fresh snow will be a potential weak layer for slab avalanches. In the region of the Zillertal Alps and northernmost parts of East Tirol, the current assumption in glaciated regions is that fractures could well penetrate down to deeper layers of the snowpack, thus making avalanches grow to dangerously large size.
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| The few snowpack analyses show fractures especially in the layers closest to the upper surface. (Photo: 12.11.2019) |
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| Snow profile from 12 November 2019 in the Zillertal Alps. The soft fresh snow on the surface could be the weak layer for approaching snowfall. In case of a heavier snow burden, fractures near ground level are also possible. |
Outlook
According to an old peasant proverb, if it snows before St. Martin’s Day over the Inn River, winter is already over. That might hold true, for it happened on St. Martin’s Day. The forecasts confirm it: for Friday, 15 November, and from Sunday to Monday, 17-18 November, additional regionally heavy snowfall is forecast for the Main Alpine Ridge and East Tirol. At this juncture, the precise intensity cannot yet be specified. The avalanche situation in the regions where snowfall has been heaviest will remain tense, at least temporarily.
