Ongoing winter in high alpine regions • Avalanches still a concern

Coolest spring for at least 25 years - Still lots of snow in the mountains

The ZAMG Weather Service recently informed us that spring 2021 is the coolest we have had in the last quarter of a century at least. Similar temperatures prevailed for the last time in 1996 and 1991, a notch cooler still in 1987.

The results are plainly visible in the mountains: winter persists at high altitudes. Potential avalanche problems due to lower-than-average temperatures are still a worry, i.e. near-surface layers. Details can be found in our last blog. Most difficult of all to evaluate is the possible formation of danger pattern “cold-on-warm” (gm.4) and “embedded graupel” (gm.9). We currently assume that these danger patterns tend to be limited to high alpine regions (above 3000m). The greatest probability of dp.4 occurring is on sunny, very steep slopes.

What helps most of all to assess the current situation, in view of the lack of up-to-date snowpack data, are near-surface stability tests you carry out yourself on-site. 

A few photographic impressions of the current situation

Slab avalanche in Grossvenediger region, appx. 3200m SW. Near-surface fracture, danger pattern dp.4 and dp.9 were the likely cause. (photo: 26.05.2021)

Deposit of a no longer fresh slab avalanche in Grossvenediger region, N 2600m. Brief period of warmth as possible trigger mechanism. (photo: 21.05.2021)

Surely the most frequent and easiest to assess: loose-snow avalanches right after snowfall.
(photo: 26.05.2021)

Loose-snow avalanches generally trigger naturally, but in extremely steep terrain they can easily be unleashed by winter sports enthusiasts. Northern Stubai Alps (photo: 23.05.2021) 

Fresh snowdrifts at high altitude. Due to low temperatures a problem at least for a brief spell, particularly near ridgelines on very steep slopes. Grossvenediger region (photo: 26.05.2021)

Caution: cornice! Even here, the Sahara dust is clearly visible. (photo: 21.05.2021)

Impressive avalanche deposits and snowplowing efforts in northern East Tirol (photo: 26.05.2021)

Not an everyday snapshot at the end of May: lush green meadows below, deep winter above.
Northern Stubai Alps (photo: 21.05.2021)

Weather station graphs on Pitztal Glacier corroborate our own gut feeling:
highly variable, cold in the mountains, windy, lots of snow.

Weather remains variable - Avalanche danger still a concern

Today, Friday 28 May, is a shining exception to the recent norm: pleasant weather. However, the cool, variable conditions have not departed, they will be with us during the coming days.

Comparatively lots of sunshine, but only today, 28.05.2021... (c) ZAMG-Weather Service

And so...in spite of the advanced juncture of the season, attentiveness is still required towards potential avalanche danger in high alpine regions.

Update of this blog: (28.05.2021 - 07:00 Uhr):

The above information about the weather referred to yesterday’s report from ZAMG Weather Service. Today’s has not yet been published. Here is an excerpt from the last valid report of ZAMG Weather Service from 28 May 2021 at 7:00 am:

“Following in the wake of a cold front, intermediate high-pressure front weather conditions will be felt today in Tirol. On the weekend, a northerly air current and a high/low will move from the Baltic Sea towards Hungary. Tirol will receive moderately moist air which particularly in eastern regions will create cloudbanks. Further west, weak high-pressure conditions will prevail. Next week we will lie at the rim of a high-pressure front. Starting on Sunday, we expect several days of dry weather, culminating in early-summer temperatures next week.”

Thus, we anticipate classic springtime conditions and daytime fluctuations of avalanche danger.

The next update of the blog will be published whenever the avalanche situation undergoes a major change.

Still wintery in high alpine regions – Avalanche danger requires attentiveness

 Regionally still lots of snow in the mountains

During a period of overly cool, highly variable weather, the snow depths in high alpine regions are still increasing. Very wintery conditions continue to reign there unchangingly. This coincides with the reports of ZAMG Weather Service: spring was this cool in 1996 and 1991.

Overall snow depths in Tirol (on 20.05.2021)

Month’s review on Pitztal Glacier. Easily recognized: very cool temperatures with frequent precipitation, often strong wind. The current overall snow depths over this last month measure a maximum.

Snow situation on 18.05.2021 in Tux Valley

For comparison, one year ago, on 18.05.2020

Snowscape on 07.05.2021 in Axamer Lizum

For comparison, a year ago, on 09.05.2020

Fresh snow on 15.05.2021 on Stubai Glacier

Avalanche danger still requires high attentiveness

Although we currently have little information about snowpack layering at high altitudes, we currently assume problems in near-surface layers. Among these:

• Snowdrift problem: 
• particularly in high alpine regions, mostly near ridgelines; especially during or immediately following precipitation
• Fresh-snow problem: 
• Graupel: We know of massive graupel deposits regionally in near-surface layers. A thick layer of graupel blanketed by snowdrifts can constitute a weak layer for slab avalanches.
• Wet loose-snow avalanches right after or during snowfall due to (diffuse) solar radiation and rising temperatures. This problem also occurs at lower altitudes where there has been heavy snowfall.
• Old-snow problem: 
• A continuing sequence of fresh snow, cold, moistening snowpack due to (diffuse) solar radiation impact harbors a high potential for danger pattern “cold-on-warm” (dp.4). We assume that this problem prevails increasingly above 3000m in all aspects in the near-surface layers. It is a treacherous risk which is exceedingly difficult to evaluate. The only thing which helps to clarify the conundrum is a view inside the snowpack and stability test. Please see our last Blog. 

Numerous naturally triggered wet loose-snow avalanches in the Northern Massif above Innsbruck due to (diffuse) solar radiation. (photo: 20.05.2021)

Ground level weakening of the snowpack due to water seepage is currently not a problem (on 9 May the case for the last time). Then, isolated slab avalanches were observed on shady slopes at 2500-2700m.

Avalanche Riepenwand-Schlicker Seespitze in the northern Stubai Alps at about 2500m NW, presumably on 9 May 2021.

From our colleagues in South Tirol we were informed of an avalanche accident with fatality yesterday on the Königsspitze at 3700m. Information can be viewed here:.


Pentecost will be highly variable

Tomorrow, Friday, 21 May, a warm front will bring higher temperatures with cloudy air from the Atlantic. In the mountains it will often be stormy, particularly near the Main Alpine Ridge. On Saturday, 22 May, a cold front will follow on its heels. The snowfall level is expected to lie at 1600m. The focal point of precipitation will lie on the Main Ridge east of Ötztal. Up to 40 cm of fresh snow could fall from place to place. The air masses will remain instable and cool, i.e. conditions which we’re currently accustomed to: highly variable! For avalanche danger, see above.

 72-hr fresh-snow forecast

Illuminating views, assuring us that spring is coming, slowly but surely....

Foehn collapses – Fresh snow + wind ratchet up avalanche danger

 The winter just doesn’t want to stop...

Over the last few days, a strong southerly foehn wind was blowing in the mountains. Today (11.05) the foehn collapsed. In the southern regions, precipitation has set in. In the northern regions a cold front from the west will move in during the evening/nighttime hours.

Windspeeds reach nearly 150 km/hr on Patscherkofel

Map of precipitation 11.05, 15:00 h. In southern regions, precipitation has already set in. Hot spot currently: Timmelsjoch.

Rainfall was initially expected up to about 2500 m. The snowfall level will settle at about 1500 and 2000 m as a result of the cold front (lower in the north than in the south).

48-hr forecast of fresh snow

Avalanche danger rising

A bit of fresh snow, together with wind impact, will increase avalanche danger. We expect large-sized naturally triggered releases in high alpine regions where there was lots of snowfall. This forecast is based on current reports of a large-sized near-surface slab avalanche near the eastern Simonyspitze in the Venediger Massif, as well as our own considerations.

Naturally triggered avalanche on eastern Simonyspitze (photo: 09.05.2021)

We currently assume that in high alpine regions a near-surface weak layer has formed due to Danger Pattern “cold-on-warm” (dp.4). With appropriate additional loading from the fresh snow it can be expected that slabs can trigger naturally, including over larger surfaces. In addition, fresh snowdrift accumulations at high altitudes can be triggered for a brief period by winter sports enthusiasts (weak layer, possibly blanketed powder or graupel). Increasingly. such danger spots are found near ridgelines in very steep terrain.

Abruptly activated fresh snow, due to diffuse solar radiation

Fresh snow at this juncture of the season reacts extremely rapidly to warmth and solar radiation. On Thursday at latest, when clouds will begin to disperse from place to place, we expect swift loss of firmness of the fresh snow. On the one hand, due to the sudden impulse of warmth; but also through naturally triggered slab avalanches. Loosely-packed snow and slab-avalanches can, subsequently, even sweep along the entire thoroughly wet snowpack with them in their plummet path.

Naturally triggered slab avalanches from 10 May due to increasing wetness of the snowpack on shady slopes. Altitude: 2500 m.

Restraint. And experience.

Thus, we anticipate a situation in which winter sports enthusiasts have gathered ample experience, where defensive strategy is called for. In addition, caution below the starting zones and in steep avalanche prone areas near canalised avalanche plummet paths is urged. There, avalanches can plummet down to low altitudes and even endanger hiking trails and forest roads.

Information on avalanche incidents on Saturday, 8 May 2021

On Saturday, 8 May, numerous winter sports enthusiasts took advantage of the fine weather and mostly favourable conditions to venture into outlying terrain. The snow cover in early morning was well frozen, except in high alpine regions. Wonderful firn snow could frequently be enjoyed on the descents. During the day, the uppermost part of the snowpack became thoroughly moist in some places, leading to small avalanches, most of which were loose-snow releases.

In high altitudes, however, an icy wind was blowing which generated wide-ranging snowdrift accumulations in ridgeline terrain. These drifts proved to be quite prone to triggering, the primary cause of the avalanche incidents which then occurred (presumably also causally combined with the Danger Pattern “cold-on-warm” {dp.4} and/or graupel {dp.9}).

Here is a brief listing of the reported avalanches:

9:30 am: Hinterer Brunnenkogel (Stubai Alps): 3300m, E/SE, no injuries 

9:55 am: Blockkogelferner (Ötztal Alps): appx. 3050, NE, no injuries

10:19 am: Böses Weibele (Schober Massif): appx. 3000m, NE, 2 persons w/airbags, no injuries

10:49 am: Tonigenkogel (Ridnaun Massif): appx. 2900m, E, slide, no injuries

11:32 am: Watzespitze (Kaunergrat): 3400m, E, 2 persons injured

11:36 am: Weisskugel (Weisskugel Massif): 3700m, E

Avalanche accident Watzespitze. The slab fractured near the ridgeline when 2 persons were ascending on foot. The circle pinpoints their ski depot. (photo: 08.05.2021)

Webcam overview of avalanche below the Weisskugel

Detail of avalanche below Weisskugel. Arrow points to several descending tracks. One person was caught by the slab and injured, brought to the hospital in Merano. (photo: 08.05.2021)

For Sunday, 9 May, extraordinarily warm weather is forecast. The danger of wet-snow avalanches will swiftly increase. The time window permitted for safe backcountry ventures is significantly smaller than on Saturday, 8 May. This is recognizable on current weather graphs.

The air is currently moister and warmer than at the same time on the previous day. The nocturnal outgoing radiation and snowpack cooling will be poorer in comparison.

Our tip: better to start very early, head high up, and be back at your point of departure as early as possible. Special caution necessary around ridgeline snowdrifts in particular, also potential weak near-surface layers (see Blog). We wish all mothers a Happy Mothers Day!

Still wintery in the mountains – Very warm weekend ahead – Rising danger of wet-snow avalanches

Sudden warmth impulse harbors heightened wet-snow avalanche potential

Still lots of snow in the mountains

The ZAMG Weather Service today published a notice of striking and powerful impulses of warmth which will bring about increased snowmelt between Sunday, 9 May and latest Wednesday, 12 May. It is a result of the still immense amounts of snow on the ground at this juncture of the season. Particularly on shady slopes, above-average snow depths are evident down to intermediate altitudes. The situation at very high altitudes is similar in all aspects.

Overall snow depths on 6 May 2021

Quite characteristic portrait of the snow situation at intermediate altitude: south-facing slopes are bare, on north-facing slopes descents are often skiable right down to the point of departure. Northern Stubai Alps
(photo: 30.04.2021)

 In the meantime, 1961 record-breaking snow depths in Obertilliach flat terrain have long been passed...

Caution: heightened avalanche danger due to warmth and prognosticated rain!

Relevant to risk: this weather forecast means increasing avalanche activity.

Warmth over the next few days will lead to more frequent avalanches. Photo from Defereggental on 29.04.2021

Following the cold front (which passed through Tirol on Thursday night, 6 May, bringing 10 to 30 cm of fresh snow) weather conditions are expected to improve swiftly and radically, bringing numerous loose-snow avalanches in extremely steep terrain on Saturday at latest.

Fresh snow forecast for 6-7 May

Particularly in wind-protected ridgeline terrain, the likelihood will increase that backcountry skiers and freeriders will trigger the snowdrift accumulations at high altitude. Starting on Sunday, 9 May, a day on which veritable summertime temperatures of 0° at 3900m are expected to be reached, the moistening of the snowpack will progress rapidly. More than anywhere else on shady slopes where moistening previously had not penetrated deep down into the snowpack, avalanches can then fracture down to deep layers and grow to dangerously large size. (Caution also urged on forest roads and hiking trails below higher-altitude starting zones!) The danger of such avalanches is expected to ratchet up a further notch on Monday evening, 10 May, when rainfall up to 3000 m is anticipated on the Main Alpine Ridge, coming from the south. Fractures of slab avalanches are then possible above about 2400m.

At high altitudes on shady slopes, a treacherous avalanche situation (dp.4 – cold on warm) could develop.

An avalanche release on the steep flank of the Petersenspitze in the rear Pitztal indicates a near-surface weak layer which was possibly formed through the swift development of danger pattern “cold-on-warm” occurring at altitudes around 3000m. Equally conceivable, although somewhat less likely in this case, is a massive layer of graupel generated during the brief bout of snowfall. Currently, we lack snowpack analysis at this altitude to be certain.

A slab avalanche triggered during the descent of winter sports enthusiasts. The striking altitude drop in the middle of the slope is probably the result of dp.4 (cold-on-warm).

Review of last week

Highly variable


Several times in sequence, and now once again, we must call the past week ‘highly variable.’ And not only the weather was variable, so were avalanche conditions.

Unseasonably cool, repeated rounds of precipitation, two days of beautiful weather, very windy most of the time in the mountains

Loose-snow and slab avalanches, yes, but also great conditions and powder snow.

Friday, 30 April, was quite a ‘steamy’ day in North Tirol. Clouds dispersed following nighttime precipitation. Solar radiation was diffuse, the sudden impulse of warmth was sharp in the snowpack. In retrospect, it was a day with frequent avalanches, including slab avalanches in the expected altitude zones. Frequently, slab avalanches were themselves triggered by loose-snow avalanches.

Cloudbanks clinging to mountain flanks amid sunshine lead to increased longwave outgoing radiation and, thereby, to faster moistening of the snowpack. Griesskogel Massif (photo: 30.04.2021)

Just after the above photo was taken, an avalanche triggered naturally. Initially, a loose-snow avalanche. Then it became a slab avalanche Griesskogel Massif  (photo: 30.04.2021)

Slab-plus-loose-snow avalanches, northern Stubai Alps (photo: 30.04.2021)

On 1 May a slab avalanche triggered just below the rocks on a shady slope due to advanced moistening.
It led to a rescue operation. No one was buried. Axamer Lizum (photo: 01.05.2021)

This photo is also from the Axamer Lizum, taken on 4 May. The avalanche releases probably occurred on 30 April – 1 May.

A cold front brought fresh snow on 2-3 May. Part of it was (briefly) terrific powder at high altitude.

48-hr snow depth differences: snowfall since the evening of 1 May

We don’t want to create a false impression. There were also plenty of great conditions last week. Above, dream-come-true powder snow in the northern Stubai Alps. (photo. 03.05.2021)

Typical of the season: numerous loose-snow avalanches after snowfall. Defereggen (photo: 03.05.2021)

Strong westerly winds in the mountains led to snow transport. Mieming Massif. (photo: 05.05.2021)

Final daily Avalanche Bulletin next weekend

We cite a statement of a colleague in South Tirol from their Blog: “Next weekend the final Avalanche Bulletin of the season will be published. However, no bulletins does not mean no avalanche danger. There is still a lot of snow in the mountains, the risks have to be seen, measured and responded to. Information on the snow-and-avalanche situation will be published in a blog if there are major changes.”