100 years of the Sandling landslide
100 years ago, in September 1920, a massive landslide occurred in the West Face of Sandling. The so-called "Pulverhörndl", around 200 m high, which split off from the West Face of Sandling in a landslide in 1765, collapsed in September 1920.
In May 1907 the summit was first climbed. Namely by the Ischl mountain guides Mathias Röchenbauer and Alois Wazinger. A cairn visible from afar at the summit testified to your first ascent. In the years that followed, the summit was climbed more often and the summit stone man soon gathered cards from the best Upper Austrian climbers.
Der Sandlingturm, aufgenommen von Franz Maier, 1915.
The west side of the Sandling summit with the Pulverhörndl in front of the landslide and the old scree heaps.
In anticipation of the catastrophe, the builder, Weinzierl, had the pictured house of the alpine grass garden relocated to the foot of the Raschberg to the west of the stream.
The western face of Sandling Peak after the landslide. On the far left, the seating area separates parts of the old scree heap from the new giant screed.
About the geology:
The Sandling has always been a troubled mountain . Namely, there is a high limestone on plastic Haselgebirge. And 1920 was a very wet, rainy year. This precipitation penetrated through the fissured and waterlogged limestone and marl and softened the underlying clayey layers. In addition, in the Ausseer salt mine in 1920 there were several "heavenly collapses", which destabilized the base of the rock masses of the "Pulverhörndl" just above. Beginning in the spring of 1920, salvos of rock pelted through the West Face of Sandling. Throughout the summer, much more frequently than usual, mighty boulders broke from the weathered rock and thundered down into the valley.
Sandling rock stratification, Otto Lehmann 1926
The catastrophe:
The sodden layers became this rainy summer literally squeezed out by the solid limestone marls and the limestone resting on them on the west wall.
Then, on September 12, 1920, the unheard of happened . 20 people were still on the Vordersandlingalm. In the morning there was increasingly heavy rockfall from the west face, which was increasing constant noise. A climber who approached the summit from Altausse at 1 p.m. thought he heard train traffic, which surprised him because the railway lines were interrupted due to the heavy rain. The view down was already blocked by billowing clouds of dust.
At about 4:30 p.m., even more violent boulder falls occurred, notably from the large rock pillars and pinnacles that towered between the Pulverhörndl and the face of the mountain. This was probably the time when the tower moved away from the wall, exposing the rocks wedged behind it. Cracks and faults became visible to the right of the tower, and the forest below slowly sank to the depths. At 5:30 p.m., a dairymaid noticed with horror that the Almboden was beginning to burst. Towards evening the mountain calmed down to some extent after most of the rocks between the Pulverhörndl and the wall had fallen down. Rock masses were no longer pressing on the back of the tower. But on the front, the pressure from the fallen rocks has increased considerably. The Pulverhörndl was now a bit shifted and isolated from the mountain up.
But nobody took that as an opportunity to leave the Alm, only sleeping was out of the question. Around 11:00 p.m., a terrible roar began again, and a commotion was already felt in the ground. It was new moon and therefore pitch black, dust covered the pasture, lanterns could not illuminate anything. Now the fear was great: Valuables were hastily buried at the foot of the "Diebskögel" and the decision was made to leave the pasture and the cattle quickly. And not via the usual Almweg south along the Michelhallbach, but via the Raschberg to the Hütteneckalm. No one was harmed by this prudence!
The Powder Tower collapsed on the night of September 13 with deafening thunder. Approx. 200,000 m3 of rock poured towards Michelhallbach. A large part of the overlying rock of the Sandlingalm was then torn down, creating a 400 m wide and 100 m deep shell-shaped crack.
Incidentally, the entire Sandling was shaken, the entire western wall was speckled with light from stones that had broken out, and the trail through the western wall was then in a desolate condition.
The Alm after the disaster:
The four huts that were lifted and moved when the Almgrund was devastated. From the fourth by H. Joh. Reisenauer you can only see the ruins on the right in front.
The "Diebskögerl" and the pressed and advanced Almgrund, which filled the meadow valley of the stream and leveled it. The objects (clothes and tools) buried at the foot of the "Diebskögerl" on September 12 were completely buried and have remained lost.
The Mure:
A huge debris flow moved down the valley. Only the southern part of the moraine mass, which had started to move, lost its connection and ended up as a mudflow. The upper, northern part was only loosened and sunk about 40 m deep into the trough created by the outflow of the Haselgebirge.
On September 14th, a forest ranger from Bad Goisern, Paul Elsenwenger, was watching the debris flow from the foot of the Raschbergwand when the surrounding forest suddenly began to sway, the ground crunched, roots broke. He was only just able to save himself on the rocky valley wall!
The Mure now filled the creek bed of the Michelhallbach and the large Zlambach for about 3.7 km and has dammed the spring streams that flow in on the east side to form two small lakes. 50 m / hour was the initial speed of the Murkopf and covered 2 km in the first 6 days. In the next 10 days he advanced another 1.2 km and in the next 15 days he came to a halt after a total of 3.7 km.
View towards the southern part of the eastern tear-out niche. A shattered mound of lias marl covered with tree corpses.
The rounded rock tower behind heralds the appearance of the Hallstatt limestone on the eastern slope.
Tree corpses covered the debris flow.
Reservoir at the mouth of a side stream.
Just before it flows into the Zlambach, the Mure divided and an island was formed on which the handsome and spacious Leisling wooden room stood. This was dismantled in days of hard work and salvaged by hand.
Witnesses of historical rockfall catastrophes can be found at the foot of the rock tower "Uh-sinnig Kira" (popular expression for "mad scream") at the Michelhallbach. Judging from archaeological excavations, there was already a rockfall accident there during Roman times (approx. in the 5th century AD) . There is historically reliable information about another catastrophe in the spring of 1546 , in which the surface facility of the small Michlhallbach salt mine was buried by a rock avalanche and claimed victims among the miners.
The rock flow of 1920 also revealed evidence of this salt mine, namely a weak brine spring. It had been dyed red and exposed in several places.
Literature:
Company newspaper of the Austrian saltworks April 1928, Bergrat Ing. Hans Reinl
The devastation in the Sandlin group, Otto Lehmann, 1926
Geological Map of the Republic of Austria Sheet 96 Bad Ischl, 2012
Mass movements in the hard-to-soft system and their anthropogenic influence, Weidinger JT, Spitzbart I. 2005
Vordersandlingalm 2020
Sandling West Face February 25, 2020 from a helicopter perspective by Raich Markus: