Delicate situation regionally for winter sports enthusiasts. Two fatal avalanche accidents in Stubai Alps.

 Numerous naturally triggered avalanches

We have just completed a phase of numerous naturally triggered avalanches. Some were very large and swept over exposed transportation routes, primarily in the western regions where snowfall was heaviest. Due to higher temperatures and rain impact, glide-snow avalanches have also increased. Particularly in East Tirol where snowfall has been heavy, some large-sized releases provide ample evidence.

Naturally triggered avalanche activity has receded significantly. Today (30.01) isolated releases in western regions were reported. The reason seems to have been additional snowpack loading due to heavy snow transport. Starting tomorrow (31.01) thewinds should be far lighter. Impulses for naturally triggered avalanches could then come from diffuse radiation effects (near cloudbanks) although that is still hard to predict.

Situation for wintersports enthusiasts remains treacherous regionally

What remains is a regionally delicate situation for wintersports enthusiasts. This applies primarily to zones above the treeline. Below that altitude, due to rain and warmth, most of the weak layers inside the snowpack have either been activated already, or have dissolved. At low and intermediate altitudes the danger of glide-snow or (in extremely steep, rain-impacted terrain) wet loose-snow avalanches remains.

Above the timberline, on the other hand, wide-ranging snowdrift masses have been generated by snowfall and wind. These constitute the perfect “slab” and can be easily triggered by wintersports enthusiasts, particularly in transitions from shallow to deep snow. In isolated cases, even remote triggerings have been reported over the last few days – something characteristic of large-spread weak layers, mostly at mid-level in the snowpack. Since avalanches can fracture down to more deeply embedded layers of the snow cover, they can then grow to dangerous size for wintersports enthusiasts.

Several recent avalanches involved persons, two with fatal results

Since mid-January we have experienced a period in which increasingly frequent avalanches have involved persons and this period seems to be continuing. Headquarters today received seven reports of such avalanches, plus one of a cornice breaking (Zwölferkogel) and a rooftop avalanche in Lienz. The releases in East Tirol were on Hollbrucker Spitze on the Carnic Ridge and on Figerhorn in the Glockner Massif. The other avalanches were all in the Stubai Alps, increasingly in the Sellraintal: Schafzöllen, Vorderer Grieskogel, Neunerkogel, Widdersbergsattel and Zubusserkopf near Trins).

What we already know about the fatal avalanche accidents

Avalanche Neunerkogel (northern Stubai Alps)

The slab avalanche triggered when a person was in the 40° steep north-facing descent at approximately 2150 m altitude. The avalanche was about 150 m long and 80 m wide. The person did not have a transceiver, was found by an avalanche dog, buried about 50 cm beneath the surface. Resuscitation attempts were in vain.

Screenshot from www.lawis.at: the accident spot is visible below Finstertal Reservoir in the Kühtai. Near the avalanche, our observer Lukas Ruetz made a snow profile after the accident. At right, the results of this profile: the avalanche triggered in the wide-ranging weak layer in the middle of the snowpack.

Avalanche Widdersbergersattel (northern Stubai Alps)

According to information of the rescue team leader (Mountain Rescue Axams) one sole tourer was in the ascent up the Widdersberg, departing from Axamer Lizum, and was buried by a slab avalanche beneath nearly 2 metres of snow. The avalanche was about 100 m wide, triggered right beneath the Widdersberger Sattel at about 2260 m altitude. The slope faced E-SE. Two persons saw the avalanche and the ski tracks leading into it, were able to immediately find the spot where he was buried. After about 40 minutes, the C1 crew was on-site, engaged in resuscitation attempts, which did not succeed. We assume, due to the similarity of terrain and snowpack analysis, that the problem causing the avalanche was the same as on the Neunerkogel. 

Approximate site of avalanche beneath the Widdersbergersattel. (c) tiris

 

A footnote (20 min following publication):

We just received notice that someone who was involved in the search-and-rescue operation after the avalanche beneath Vorderer Grieskogel, Kühtai, requested that we publish the following: the avalanche path was in the immediate vicinity of the Kaiserjochbahn. Persons who were on the lift and had their beacon devices turned on influenced the search enormously. Possibly there is a lesson to be learned: that lift personnel should ask people to turn off their beacons in the lift.

Avalanche Vorderer Grieskogel. Search-and-rescue team and Kaiserjochbahn
(photo: (c) Gerold Santer on 30.01.2021)

Help us avoid unnecessary rescue operations - Please report all “non-injury” avalanches to headquarters!

Avalanches involving persons with definitely no injuries, i.e. where help is unnecessary, are called “negative avalanches” by Avalanche Headquarters in Tirol. In order to avoid all cost-intensive avalanche operations, we appeal to winter sports enthusiasts to report all negative avalanches to headquarters. Please call Avalanche Emergency tel. no. 140 to report these directly!

Please also report avalanches with injuries and/or persons buried in snow at the Avalanche Emergency tel. no. 140 or at „SOS EU Alp" App on your cell phone.

Exemplary reaction following an avalanche without injuries: this avalanche was immediately reported to headquarters. (photo: 30.12.2020)

Thank you for your assistance! Spread the message to as many winter sports enthusiasts as possible.

Avalanche Warning Service Tirol, Headquarters Tirol

Warm front + snowfall + storm wind leading to significant increase in avalanche danger. Naturally triggered avalanches expected.

Breaking news: Big daytime rise in risks today (28.01.21). High avalanche danger.

A warm front from the Atlantic has been generating our weather conditions since yesterday (27.01) and, consequently, also our avalanche conditions. Most of the precipitation is anticipated in the western, also in the northern regions of North Tirol. ZAMG Weather Service forecasts 40-60 cm of fresh snow for today in the main areas of precipitation, more from place to place. Accompanying the precipitation will be a continual rise in temperatures plus increasingly stormy winds.

72-hr snowfall forecast since 27.01. 07:00 am

Wind forecast for today, 28.01. 4:00 pm - Storm in the mountains.

Current conditions measured at Jamtal Refuge, Silvretta: snowfall amid rising temperatures.
The fresh snow is dry, fell at low temperatures in many places.

This combination, coupled to the current snowpack layering, guarantees numerous naturally triggered slab avalanches. For that reason, we have classified today’s danger in most parts of North Tirol as high, seen through the lens of a daytime cycle.

Danger-level map for 28.01.2021 - Hour-by-hour increase in danger.

In addition, as a result of rising temperatures, together with rain, increasingly frequent glide-snow and wet-snow avalanches are expected to release. Exposed transportation routes are at risk.

Thoroughly moist snowpack and additional loading of fresh snow: that pushes snowpacks to just glide away over steep, smooth slopes, as here on a meadow. Defereggental (photo: 24.01.2021)

A review, to make the current situation easily graspable

Short weather review

Last week was turbulent, highly variable. The southerly foehn was replaced on Friday night by a cold front (23.01). At that time, the focal point of the precipitation was, once again, the southern regions.

72-hr difference in snow depths: 22.01.-25.01.2021

On Monday (25.01) moist, cold air masses brought snowfall from the northwest, focal point: northern barrier cloud zones.

48-hr difference in snow depths: 25.01.-27.01.2021

And now, a warm front is heading our way which will be replaced by further cold-and-warm fronts (less intensive than the current front).

A glimpse inside the snowpack

Decisive in the current situation is the loosely-packed, still cold powder on the snowpack surface. Due to today’s precipitation with rising temperatures and winds (28.01), the uppermost layers to an increasing extent will bond together. This will generate large-sized “slabs” which will bond extremely poorly with the cold powder snow on top. Subsequently, numerous naturally triggered slab avalanches will release in the loosely-packed powder. In many cases, the snowpack loading will initiate fractures down to other weak layers more deeply embedded in the snowpack. Avalanches in the major areas of precipitation can for that reason grow to very large size in some cases. What suggests the secondary fractures: recent stability tests conducted throughout the land. Fractures were frequently propagated, even by only medium loading. Therein lies one of the fundamental prerequisites of slab avalanches.

Snowpack analysis on 27.01, Hafelekar, Northern Alps. The surface is loosely-packed in many zones. Inside the snowpack are softer, trigger-sensitive weak layers.

Slide-Block Test during an Avalanche Commission course in Defereggental (c) LK Defereggen

A typical snapshot: loosely-packed surface snow, weak layer in the middle of the snowpack (of faceted crystals from the cold phase in mid-January). NE, 2120m

A similar situation on sunny slopes: S, 2240m

Avalanches during the recent week

Avalanche Poverer Jöchl on 22.01.2021 - Tux Alps. Large-spread weak layers from the cold phase

Naturally triggered avalanches following snowfall as of 22.01. - south-facing - Deferegger mountains

A similar picture to the previous one, Schober Massif (photo: 24.01.2021)

Avalanche near a forest zone. Niederberg (photo: 25.01.2021)

This naturally triggered slab avalanche developed a powder cloud. Glockner Massif (c) foto-webcam

Tense avalanche situation for winter sports enthusiasts. Avalanche analysis and outlook.

First things first: the delicate, treacherous avalanche situation will persist for winter sports enthusiasts. So we continue to advise: high restraint in outlying terrain!

Numerous reports from winter sports enthusiasts, ardent snowpack examinations and meticulous accident analysis all confirm, unfortunately, that the avalanche situation for winter sports enthusiasts remains very tense. Making things worse, the weather forecast of ZAMG Weather Service foresees turbulent weather conditions approaching.

An important foundation of our work: snowpack examination including stability tests. Above, avalanche commission members in the Arlberg region examine the snowpack near avalanche fracture zones. The tests on southwest-facing slopes at 2150 m showed a snowpack highly prone to triggering.
(photo: 16.01.2021)

Stability tests nearly a week later: fractures propagate frequently through an entire block, and mostly with only minimum additional loading, indicating an ongoingly trigger-sensitive snowpack.         Axamer Lizum  (photo: 21.01.2021)

Overview of recent avalanche releases

As mentioned in recent blogs, numerous avalanches released naturally last week or were triggered by winter sports enthusiasts. Here is an overview of the avalanches involving persons we are aware of.

Highly unusual: recently reported avalanches in Tirol involving persons. To date, two persons suffered injuries, one of them is in critical condition.

Short analysis of the avalanche accident on 20.01.2021 on the Wanglspitze in the eastern Tux Alps


Today, on 21 January, we traveled to the avalanche accident site together with the Alpine Police and one of our observers. This avalanche was a slab release. It was approximately 400 m long and 35 m wide, had an average fracture depth of 30 cm. The fracture area is at 2270 m altitude on an east-facing slope. The avalanche terrain is extremely steep (gradient between 40 and 45°).

The avalanche was triggered just after 11:30 am on 20 January at an altitude of 2270 m when a person was in the descent. The person was swept along and buried in a gully about 2 metres deep. The accompanying friends rushed swiftly to the site and were able to dig out the buried person in about 30 minutes. Efforts were made at resuscitation while the person was being flown to the hospital. On 19.01 a slab had already released just 100 metres altitude below this fracture. Also then, skiers were in the descent at the time. No one was injured.

Avalanche Wanglspitze: avalanche accident on 20.01.2021 in magenta. Additional slab on 19.01.2021 in turquoise

Plummet zone of avalanche, including point of burial (photo: 21.01.2021)

The steepest point in the avalanche track (photo: 21.01.2021)

Snow profile in fracture zone: visible are the shallow masses of fresh snow and snowdrifts. Beneath those are very loosely-packed, faceted crystals - the weak layer. Below that, the snowpack becomes more compact. (photo: 21.01.2021)

Snow profile from an undisturbed spot orographically right of the avalanche track about 100 metres of altitude below the fracture. Visible: the loosely-packed, faceted layer which formed during the long period of low temperatures. At the site, this layer was extremely prone to triggering.

Other avalanches

Pictures are known to be worth more than a thousand words. Below, a selection of photographs recently sent to us of avalanches involving persons. There were no injuries in any of them.

Avalanche Pleisen - Axamer Lizum - northern Stubai Alps (photo: 15.01.2021)

Avalanche Diasalpe - eastern Verwall Massif (photo: 16.01.2021)

Avalanche Finstertal-Staumauer - northern Stubai Alps (photo: 16.01.2021)

Avalanche Schönberglspitze - central East Tirol (photo: 16.01.2021)

Avalanche Hafelekar direttissima - Karwendel (photo: 19.01.2021)

Avalanches Nauders - Tscheyegg - Glockturm Massif. These avalanches were remotely triggered from a spot in the upper third of the picture. (photo: 19.01.2021)

Avalanche Roter Kogel - northern Stubai Alps. One person was in the ascent, traversed on skins and triggered the avalanche remotely. (photo: 20.01.2021)

Avalanche Roter Kogel - northern Stubai Alps. In the circle is the person who remotely triggered both avalanches. Compare with photograph above. (photo: 20.01.2021)

Avalanche Wankspitze - Mieming Massif (photo: 21.01.2021)

As a result of storm-strength winds and fresh snow, again more naturally triggered avalanches

Currently, reports are accumulating of naturally triggered avalanches due to additional loading of the fresh fallen snow. To blame: the strong to storm-strength southerly foehn wind, together with the unfavourable snowpack layering. Slab avalanches can grow to large size due to area-wide weak layers.

Vast snow transport in the mountains. eastern Tux Alps (photo: 21.01.2021)

Two days earlier, all was still white, now utterly windblown. The foehn leaves no snowflake unturned.  Bleispitze - Ausserfern (photo: 21.01.2021)

Naturally triggered slab avalanche on 21.01.2021 due to snow transport. Hönig - Berwang - Ausserfern (photo: 21.01.2021)

Naturally triggered slab avalanche Senderstal on 21.01.2021 - northern Stubai Alps (photo: 21.01.2021)

Things remain tense. For winter sports enthusiasts: dangerous.

A glimpse at the weather stations shows, among other things, the rather turbulent weather development thus far. ZAMG forecasts also show that turbulent conditions aren’t over yet. Avalanche danger is unchanged: still a “tense level 3.” The outlook: higher danger still, again approaching Danger Level 4.

Seegrube weather station, where the heaviest snowfall was registered this last week.
In a nutshell: variable winds, variable temperatures. Currently stormy, quite warm.

Snowfall forecast for the coming days: a southerly air current will bring another batch of fresh snow to southern regions.

Tense wind forecast: a powerful southerly air current persists in eastern regions; a new perturbance is pushing eastward from the northwest

The upshot: if avalanches are the enigma, the terrain is usually the solution.

During a treacherous avalanche phase, backcountry tours in more moderate terrain are the answer (of course taking into consideration avalanche starting zones to avoid risks of remotely triggered or naturally triggered avalanches). The advantage: no worries, utterly enjoyable tours. 

One last point at the end of the blog: due to higher temperatures in the last few days, the snowpack at low and intermediate altitudes has become less prone to triggering. The outlook is also better at that altitude. But above the timberline, things rapidly turn critical.

Numerous avalanches involving persons sound the alarm: caution + restraint!

 

Since the snowfall of 12-13 January we have had an (initially) extremely dangerous and (now) a thoroughly delicate avalanche situation in far-reaching parts of North Tirol and in northern East Tirol. Currently, the alarm signals continue for winter sports enthusiasts: whumpf noises, fracture cracks, some remote triggerings and isolated naturally triggered avalanches. Moreover, snowpack analysis shows that the weak layers which were generated during the phase of low temperatures are still easily triggered. These are crystal-clear indicators of a high Danger Level 3 (“Considerable”) - what we call a “tense 3.”

Numerous avalanches involving persons

In addition, since the end of the cold phase, headquarters has received numerous reports of avalanches involving persons. Until yesterday, 19 January, no one had been injured. Today, 20 January, however, someone need to be resuscitated and brought to the hospital (avalanche accident Wanglspitze) and a further person suffered injuries (avalanche accident Rossgruberkogel). A list of the recent avalanches can be viewed at LAWIS.

Avalanche accident Wanglspitze

Tomorrow, 21 January, we will examine on-site the accident below the Wanglspitze together with the Alpine Police. Further information and a comprehensive review of this last week will be published tomorrow (21 January) in a new blog.

Wanglspitze in the eastern Tux Alps on 20.01.2021. The avalanche was triggered when someone was in the descent. The person was completely buried, needed to be resuscitated and flown to the hospital. (photo: 20.01.2021) 

Extremely trigger-sensitive snowpack = extreme restraint necessary in outlying terrain in next few days! Growing risks for endangered transportation routes in western regions.

Alarm bells of nature: naturally triggered slab avalanches, settling noises, fracture cracks, remote triggerings!

From all corners of Tirol, a great many reports of an unusually trigger-sensitive snowpack came in today, 14 January. Settling noises, fracture cracks and (remote) triggerings of slab avalanches unrolled regularly in flat-to-moderately steep terrain. Artificial triggerings with explosives succeeded over large-spread areas. Peter Raich, one of our observers in Ötztal, even reported that two large slab avalanches were triggered on the Gaislachkogel by just the tiny impulse of the the explosive placement on the snowpack, i.e. without detonation.

Countless danger zones

The current situation is unusual also because the distrubution of avalanche prone locations is quite high throughout the land. For that reason, a great many naturally triggered (medium to large-sized) avalanches have triggered. That means triggering slab avalanches by winter sports enthusiasts is highly likely in steep terrain. In addition, remote triggerings from flat terrain are an ongoing threat.

A selection of current photos:

Naturally triggered slab in a forest clearance on Geigenkamm, Ötztal (photo: 14.01.2021)

Just one of countless hillside snowslides, Kitzbühel Alps (photo: 14.01.2021)

Typical of a hair-trigger weak layer: avalanches release even where the snow is shallow. In such a case, snow-blockage constructions placed on the slope have no effect. Lärchfilzkogel (photo: 14.01.2021)

Fracture cracks opening. Ausserfern (photo: 13.01.2021)

View into the snowpack: at bottom, rough-grained old snow; at top, the mass of fresh snow. Bichlbach (photo: 13.01.2021)

No, not glide-snow, but a slab avalanche on the roof, due to weak layer plus bonded fresh snow. Gerlos (photo: 14.01.2021)

Fracture cracks due to additional loading of one skier. Rosshütte (photo: 14.01.2021)

Slab avalanche on a hillside buries a secondary road in Sölden. The avalanche was triggered by backcountry skiers. (photo: 14.01.2021)

Additional similar avalanches burying roads were reported in Arzl im Pitztal, Reith im Alpbachtal and between Gries am Brenner and the national border.

Slab avalanche with powder cloud, Venediger Massif (photo: 13.01.2021)

A hidden risk in heavy snowfall areas: tree breakage. Ausserfern (photo: 14.01.2021)

Weather of the last few days

Two cold fronts with a warm front wedged between them since 12 January are the cause of recent snowfall and precipitation in Tirol. This time it struck the northern regions (long awaited). The forecasts had to be ongoingly ratcheted up because of the warm front. Ultimately there was 100 cm of fresh snow registered regionally, in some places nearly 200 cm. Currently (14 January, 10:50 pm) it is uncertain how the warm front will further affect weather conditions. The precipitation could become even heavier than anticipated, which would have adverse effects on the magnitude of naturally triggered avalanches. That would increase risks to exposed transportation routes, particularly where snowfall has been heaviest. The especially dangerous factor was, and still is, the storm-strength W-NW-N wind which is generating such wide-ranging snowdrift accumulations.

48-hr snow depths: hotspots in the north.

Most snowfall was registered at the Alplhütte in the Mieming Massif.

Seegrube weather station data. Lots of fresh snow, storm winds. Also the temperature rise on 13-14.01 is interesting. Nocturnal warming led to rainfall at lower altitude. Temperature fluctuations during snowfall can reinforce a weak layer inside the fresh snow (possibly delayed by dp.3 - cold on warm).

Naturally triggered avalanches still possible

As precipitation eases (tomorrow morning 15.01 at latest) the frequency of naturally triggered slab avalanches will drop markedly. Naturally triggered slab avalanches will then be possible primarily where continuing snow transport leads to persistent additional loading of the snowpack. Also solar radiation could initiate naturally triggered slab avalanches. In our experience, artificial triggerings over the next few days promise a high degree of success.

Highly accident-prone days lie ahead of us.  Play your part: keep out of harm’s way!

Better weather is forecast for the coming days, according to ZAMG Weather Service. In the past, precisely that situation (fine weather, highly trigger-sensitive snowpack, lots of fresh snow and wind) invariably has led to a host of avalanche accidents.

Thus far, all the avalanches have been without damage or injury. We sincerely hope it stays that way. For this reason we appeal to the common sense of winter sports enthusiasts: please stay on secured ski slopes for the next few days! Venture into outlying terrain only if you possess extremely good avalanche-assessing knowledge. And then, act defensively. There are uncountable dangers lurking in outlying terrain currently. Our assigning Danger Level 4 (“high”) was not undertaken haphazardly. Follow the Avalanche Bulletin at www.lawinen.report. Conditions and avalanche forecasts are updated every morning, as weather developments change.