Heavy snowfall in coming days, rising avalanche danger

Lots of fresh snow, particularly in East Tirol and along the Main Alpine Ridge, will build up new snowpack depths. As a result, avalanche danger will rise to new heights in those regions. North of the Inn there is comparatively little snow, and less precipitation is anticipated there.

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.

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.

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.

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.

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.

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.

The few snowpack analyses show fractures especially in the layers closest to the upper surface. (Photo: 12.11.2019)

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. 

Avalanche accident in freeriding terrain of Sölden’s glacier zone

Today on 9 November, headquarters in Tirol reported an afternoon avalanche on the Rettenbachferner in Ötztal valley. It was a slab avalanche that triggered when 2 persons were in theier descent path. The accident slope is on the shady flank at about 2800 m and is dotted with rocks.

The red elliptical zone indicates the accident zone.

Together with the Alpine Police, we will conduct investigations tomorrow (10 November). Further details added to the snowpack layering will be published on Tuesday, 12 November.

Caution urged at high altitudes and in high alpine zones: heightened likelihood of avalanche accidents after stormy period followed by weather improvement

Just to round out the last blog entry:

In the mountains of the Europaregion there is already snow in the heights:

Webcam photo from Pejo 3000 m towards Rifugio Vioz-Mantova (07.11.2019)

The bad-weather front arrived from the south.

Animated depiction of the Zugspitze webcam of the bad-weather front approaching from the south.

Throughout the Europaregion Tirol/South Tirol/Trentino it has been raining or snowing, with the amounts of accumlating precipitation significantly increasing from north to south.

Precipitation in the last 24 hours (recorded 08.11.2019, 1:50 pm) in South Tirol

Snowfall in rearmost Stubai Valley (Photo: 08.11.2019)

The storm-strength southerly wind in the mountains since 7 November is also impressive.

Weather station Patscherkofel: cold front passes through, little northerly wind (blue). Subsequently: rising temperatures and increasing wind impact from the south.

Snow transport in the mountains (Tux Alps) Photo: 07.11.2019

The accumulated amounts of precipitation turned out to be less than those anticipated in the forecasts. Nevertheless, there was 50 cm of fresh snow registered in the high alpine regions of the South, in Trentino as much as 80 cm from place to place. Snowfall-plus-wind leads to correspondingly far-reaching snow transport. We expect some naturally triggered avalanches during this stormy period, particularly in high alpine shady terrain, most of all near to ridges on leeward, very steep slopes. 

In view of the significant improvement in weather conditions expected this coming Sunday, 10 November, we permit ourselves to point out that the first fine-weather day following a stormy period of snowfall tends to be laden with accidents. Even if it is only the beginning of November, winter conditions prevail in the high alpine regions, including potential danger of triggering slab avalanches. Even the weight of one sole winter sports participant is sufficient to trigger a slab avalanche.

The first reports about glide-snow slides which are occurring ever more frequently on grass-covered slopes are highly indicative.

Numerous glide-snow slides on steep grass-covered slopes in the Tux Alps (Photo: 07.11.2019)

Glide-snow slide in the Lasörling Massif in East Tirol (Photo: 06.11.2019)

Winter conditions in the mountains, including possible avalanche danger

Highly variable weather conditions have brought some fresh snow to the mountains since the end of October. The snowfall was particularly heavy during the last few days. The amounts of fresh fallen snow in the regions along the Main Alpine Ridge and southwards therefrom were frequently about 50 cm, significantly more from place to place.

Tux Valley  (Photo: 06.11.2019)

Fresh snow on Stubai Glacier (Photo: 05.11.2019)

 In the interim, the first reports of avalanches have reached us:

27.10.2019: Naturally triggered slab avalanche near the summit of the Ortler
01.11.2019: Slab avalanche in the north face of the Hochferner, which triggered when mountaineers were there. Fracture depth: max. 10 cm.
04.11.2019: Naturally triggered slab avalanche in the Hochfeiler north face. Triggered during snowfall accompanied by wind.
05.11.2019: Successful artificial triggerings with explosives on Pitztal Glacier, including naturally triggered slab avalanches.

Naturally triggered slab avalanches: Hochfeiler north face (Photo: 04.11.2019)

Shady, very steep high alpine terrain (above 3000 m) was struck with particular vehemence recently. Indications point to the beginning of an old-snow problem. We assume that near the melt-freeze / rain crusts a weak layer of faceted crystals has formed. Rainfall on 21 October up to over 3300 m may have been the cause.

Furthermore, the first autumnal snowfall, which was limited to the high alpine zones, also played a part (first time on 8 September).

Review of last month: in October some precipitation with mostly sunny, unseasonably warm phases. As of the end of October, increasing precipitation. The arrow indicates each day when it rained up to over 3300 m.

The situation reminds us of autumn 2016, when the first avalanches of the season took place already in mid-October (Olperer, Hochferner)

Upshot: In high alpine regions the winter has already begun, avalanches are possible as of now. Winter sports fans can trigger slab avalanches even by minimum additional loading, particularly in the indicated aspects and altitudes.

At lower altitudes where there has been ample snowfall and the ground surface is smooth (especially steep grass-covered slopes), increasingly frequent glide-snow avalanches can be expected.

Please note: data of snowpack analysis and observations are still lacking. Thus, an area-wide assessment of avalanche danger is not yet possible.

What’s next?

To start with, tranquil weather conditions will arrive on Thursday. In the evening, a low over Genoa will launch some rainfall and snowfall from the southwest. By Friday morning, the precipitation will spread throughout the Main Alpine Ridge and regions to the south of it. In North Tirol, it will generally remain dry Thursday night, rainfall and snowfall will be launched on Friday. Focal point of the precipitation will clearly be the southern and eastern parts of the Europa Region. This round of precipitation will be accompanied by storm-strength southerly-to-southeasterly winds in places. On Friday night, conditions will quiet down incrementally. On Saturday morning, only isolated rainfall and snowfall are anticipated.

Total precipitation (24 hrs) in mm of the European weather model for all day Friday.

The snowfall level will be at 1000 m on Friday, in some places even lower. According to the latest weather model, the snowfall level will ascend significantly in the Dolomites during the course of the day. The prospective amounts of fresh snow are visible on the map below: 

Fresh snow forecast from Wednesday through Saturday, with settling snow.

The model for fresh snow forecasts will be updated twice daily on our website, so we recommend keeping up to date by consulting this link: https://avalanche.report/weather/map/fresh_snow

Avalanche danger will increase significantly as of this snowfall, particularly in the regions where there is a great deal of fresh snow, in high alpine zones and generally wherever the fresh fallen snow is deposited on top of an old snowpack. On steep grass-covered slopes, glide-snow avalanches can be expected, in high alpine regions naturally triggered or easily-triggered slab avalanches are anticipated. For the weekend, the avalanches risks should not be underestimated.

The next update of the avalanche situation will be published whenever the situation changes significantly.

End of season: current situation and review of winter 2018/19

An out-of-the-ordinary winter demands out-of-the-ordinary moments to write a blog....


In the first part: a brief description of the snow and avalanche situation since the end of May. In the second part: a review of the winter through data, facts and graphs.


Snow and avalanche situation between end of May and mid-June 2019

There is still an extraordinary amount of snow at high and high-alpine altitudes for this juncture of the season.

In high alpine regions, the overall snow depth is currently over 400 cm.

Even at the end of last week, skiers were sighted at altitudes above 1700 m....

An abrupt end: skiing stops at the grassy meadow. Seebensee (1660 m) in the Mieming Massif  (photo: 14.06.2019)

Let’s look at the situation since the last blog entry on 28 May through these interesting observations:

Slab avalanches triggered below Zwieselbacher Rosskogel by loose-snow avalanches. A near-to-surface weak layer briefly formed due to danger pattern cold-on-warm at the end of May. (photo: 03.06.2019)

Similar situation to previous photo near the Reichenspitz in the Zillertal Alps. (photo: 02.06.2019)

On 1 June there was even a long avalanche emergency rescue near the Kleegrube in the free-riding zone of Hintertux Glacier. In extremely steep terrain, a wet, loose-snow avalanche triggered naturally above two riders who had just entered that slope. Since the number of tracks emerging from the end of the slope deviated from the tracks entering the slope, it was assumed that one person had been buried in snow. The search was terminated when one of the two persons reported in to the police. During the emergency rescue work, additional loose-snow avalanches triggered in the immediate vicinity due to the increasing wetness of the recently fallen fresh snow.

Avalanche rescue work: Kleegrube, Hintertux Glacier (photo: 01.06.2019)

Furthermore, additional isolated glide-snow avalanches were observed, a persistent theme this winter....

At photo center, a fresh glide-snow avalanche can be seen below Langen Sattel in the Northern Massif. (photo 01.06.2019)

Still in motion: residual snow in the Karwendel  (photo: 02.06.2019)

Debris on Tannauer Alm in the Karwendel, caused by glide-snow avalanches during the intensive period of snowfall in January (photo: 02.06.2019)

Ground erosion caused by gliding snow masses. Bächental  (photo: 02.06.2019)

Easily recognized forest damages from mid-January at the Herzwiese, near Arzleralm in the Northern Massif (photo: 01.06.2019)

Backcountry ski tourers with patience and endurance found their pleasures this winter....

In the Arlberg region, it was still possible on 8 June to launch backcountry skiing tours straight from the road.

Superb conditions in high alpine regions of the Zillertal Alps  (photo: 04.06.2019)

On the northern flanks of the Mieming Massif, it frequently was (and still is) easier to be on skis than on foot.               (photo 14.06.2019)

The consequence of the unusual amount of snow and, during the last couple of weeks, unusually high temperatures, was the extraordinary highwater level of the Inn, a 30-year record which also brought about flooding in the lowlands.

Inn River on 13.06.2019

The innkeepers at mountain refuges and shepherds feel the unusual snow situation, too. The refuges are opening up later; and the sheep are being brought with three weeks delay to the high alpine pastures.


Review of season
short and sweet – our take on the winter:


Very heavy snowfall in January,
by and large good backcountry touring conditions,
relatively few avalanches involving persons,
significant forest damage,  displaced transportation routes in some areas.

Winter 2018/19 will go down in history as one which was ‘rich in snow,’ although in southern East Tirol there were no measurable amounts of snowfall until the latter part of the season.
From New Year’s until mid-January in many places in Tirol, danger level 4 (high) prevailed nearly ongoingly due to persistent heavy snowfall. On 14 January, danger levels increased even to level 5 (very high) in the Arlberg and Ausserfern regions, in the Karwendel, in the northern Zillertal Alps and in the Venediger Massif  (s. Blog).

Percentages of danger levels published daily during the overall season of the Euregio-Avalanche Bulletin                    (Source & ©: LWD-Tirol). 

As a result of significant amounts of fresh snow, there were numerous avalanches which reached great magnitude during this period. In isolated cases there were even size 5 releases (very large). This is underscored by a glance at the time sequence and unfolding of avalanche activity during the entire season.

Frequency of observed avalanches between 31.10.2018 and 20.04.2019, weighted according to size. Easily recognized are the peaks in the early part of January during the period of intense snowfall.  (Source & ©: LWD-Tirol).

A direct consequence of avalanche size was the degree of damage registered to buildings and forests, as well as burying of vehicles in snow masses. During this period, 65 damage-causing avalanches were registered.

Recorded avalanche releases during the intense snowfall period in January which reached either settled areas or transportation routes (excluding forest damages). Also depicted are the overall snow depths and air temperatures at Muttekopfhütte weather station. (Source & ©: LWD-Tirol).

Immediately following this phase, the snowpack rapidly lost its internal tensions, thereby improving the avalanche situation noticeably. A stormy southerly air current at the beginning of February again led to a tense avalanche situation (level 4 - high) particularly in East Tirol, but only for a brief spell. An accompanying factor which persisted throughout the winter was gliding snow. This problem was especially prevalent in the northwestern regions. In the southeastern regions, on the other hand, the old-snow problem was more dominant, having developed due to the long interim between the first couple of bouts of snowfall in early winter.

Geograhical distribution of all forecast avalanche problems during the winter 2018/19  (Source & ©: LWD-Tirol).

Sequence and duration of the forecast danger patterns in the Euregio-Avalanche Bulletin in winter 2018/19. Danger pattern dp.2 was a persistent presence.  (Source & ©: LWD-Tirol).

All in all, this winter season - quite like the winter of 2017/18 - can be described as a classic gliding-snow winter. In many communities, repeated burying of transportation routes and forest damages occurred. Some avalanches even penetrated into settled areas. Although releases of glide-snow avalanches are utterly unpredictable at the current level of snow research, the number of persons involved remained very low. Out of 132 glide-snow avalanches, only 6 involved persons (4.5%). Those who were affected were injured only in rare cases, and there were no fatalities. In the settled regions, this can be attributed to the outstanding collaboration and efforts of the local avalanche commissions.

A general overview of the statistics of 2018/19 reveals, once again, the inordinately large role played by snowdrifts as cause of avalanches involving persons. More than 65% of the accidents can be traced back to a snowdrift problem as avalanche cause, followed by an old-snow problem (16%).

Locations of avalanches involving persons, sub-divided into the causal avalanche problem.

In spite of a very exciting and snowy winter, including many highs and lows in all senses of the term, the number of avalanches involving persons (92 events) was slightly below the 10-year median (108 events). This can be attributed to the generally favorable conditions for winter sports activities this season. The sum of avalanche-caused fatalities this winter (5 persons) also lies below the 10-year average (10 persons).

Number of avalanche-caused fatalities in Tirol between 2009/10 and 2018/19. Thus, this season saw fewer deaths than average during the last 10 years. (Source & ©: LWD-Tirol).

A glance at the geographical distribution of this year’s avalanche events discloses the freeriding zones of Tirol’s ski areas as the hot spots of avalanche accidents. The popular ski touring regions, automatically placing them at the focus of such avalanches, were (as in the past) the regions of the northern Ötztal and Stubai Alps, Tux and Zillertal Alps.

 Avalanche activity involving persons throughout the 2018/19 winter  (Source & ©: LWD-Tirol).

Our work is now complete for the 2018/19 season.
We extend a vote of thanks for the many avalanche reports registered by private persons throughout the winter. And we wish everyone a beautiful and accident-free summer.