IDC Natural Hazards 3-day field trip to Galtür

A visit to Galtür 25 years after the avalanche disaster of 1999

from 03.-05.10.2024

 

The main target of the interdisciplinary field trip is the exploration of past and future hot spots of natural hazard processes in the Tyrolean Oberland, including new infrastructure buildings both in the vicinity and on the way to the village Galtür.

 

Ongoing global temperature rise, which is particularly pronounced in the Alpine region, has led to significant effects on glaciers and permafrost. Glacier retreat has become a prominent indicator of climate change. Besides significantly impacting runoff, these glacial changes are also heavily influencing sediment transport processes. As this year marks the tragic 25th anniversary of the avalanche disaster in Galtür in 1999, we focus on the high mountains areas of the Tyrolean Oberland and the Jamtal, where unique in-situ views of these changing processes can be recognized.

The travel to Jamtal with our stay at Jamtal hut, visit of Fluchthorn deposits and the Jamtal glacier foreland, will be accompanied by further short stops along the way at hydro power plant construction site in Kühtai and the historic Tschirgant and Habichen rock slide in the Oetz valley. The combination of studying historic natural hazards with most recent ones, the demands of combination of geotechnical, hydraulic and geological expertise for hydropower plant construction, as well as current monitoring, investigation and mitigation methods of natural hazards will allow us to get a deeper understanding of natural hazards in general and to broaden our horizon across disciplines. As an overarching theme the observed processes will also be discussed in the context of climate change during the excursion.

Besides this, the interdisciplinary field trip will provide an opportunity for mutual exchange on our individual research topics. To allow additional students to experience this unique opportunity, we would like to invite up to 9 additional PhD (and Master) students from the University of Innsbruck to join us (up to a total group size of 15 people). The interdisciplinary exchange of the excursion will further be expanded with the invitation of experts from different fields and fellow researchers. Together with the invitation of the additional PhD (and Master) students, the field trip will be a place for fruitful discussions and enable possible future cooperations.

Accommodation is reserved at the Jamtal hut for two nights, as well as two electric cars and an e-bus. In case of bad weather we may have to depart on alternative days and drive with private cars. Transport and accommodation costs (including 2x breakfast and 1x dinner at Jamtal hut) are covered by the DP Research Grant 2024. Other food costs and other expenses are not covered.

 

Figure 1: A) Galtür avanlanche disaster 1999: APA/HANS KLAUS TECHT, https://tirol.orf.at/stories/3245365/; B) Jamtalferner
outwash plain: https://www.mountainresearch.at/HiddenIce/; C) Fluchthorn: https://www.uibk.ac.at/de/newsroom/2023/3dlaserscanning-
zeigt-ausmass-des-fluchthorn-bergsturzes/; D) Kühtai Dam: Perzlmaier & Holzmann 2023, Österr Wasser- und
Abfallw 2023 75:210–218.

 

Site description:

 

  • The Kühtai pumped-storage project of TIWAG-Tiroler Wasserkraft AG, which is currently under construction expands the existing Sellrain-Silz group. Part of the project is the new Kühtai reservoir, which will be connected to the existing Finstertal reservoir via the new Kühtai 2 power plant and the associated headrace tunnel. In the course of the construction work in Längental, which has been ongoing since 2020, work has also begun on the construction of the Kühtai dam (Perzlmaier & Holzmann, 2023).

 

  • Piburgersee is composed of lacustrine mud with low background sedimentation rates (0.24 mm/year) during the Holocene.The lake shows a variety of different types of eventbeds, such as numerous flood deposits, three debrite intervals and a 2.5 m thick turbidite induced by a local rockfall impacting the lake floor at ~2.9 ka BP. Also a debrite interval is linked to the activity of the nearby Habichen rockslide at ~4.4 ka BP. Furthermore, earthquake-induced soft sediment deformation structures are found within the lake record, which are strikingly linked to large rockslides within the lakes vicinity such as Eibsee and Fernpass, as well as Tschirgant and Haiming, coincide within the overlap-age ranges of the paleo-earthquakes recorded in both lakes at 4.1 ± 0.1 and 3.0 ± 0.2 ka BP, respectively (Oswald et al. 2021).The Tschirgant rock avalanche is situated ~40km west of Innsbruck at the river mouth of the Ötz River into Inn River. Below the summit of Mount Tschirgant [2370 meters above sea level] is the location of the detachment area of the rock avalanche, the ‘Weißwand’ cliff more than 1400 m in height, with a volume of up to 230 million m3. Minimum U/Th-ages of calcite precipitations within the rock avalanche deposits, result in a probable event age of ~3.01 ± 0.10 ka BP (Ostermann et al., 2016). The rockslide deposits of Habichen are the end of the cascades of the Ötz river (Achstürze, approximately 800 m a.s.l.) caused by the Habichen rockslide, were investigated by several authors but not in detail. The failing rock masses first propagated in NE-direction towards a bedrock obstacle composed of biotite gneisses, which forced the debris to travel further on towards the East. The rockslide masses ran up the eastern valley flanks for about 100 m, and dammed the Ötz valley (Ostermann and Prager, 2014). Based on backwater sediments in the main valley the Habichen rockslide activity occurred ~6.0 – 3.4 BP (Prager et al., 2008) and dated to 4.4 ± 0.09 ka BP based on Piburgersee (Oswald et al. 2021).

 

  • In the Jamtal Valley the landscape is currently changing drastically in response to climate change. In the upper part of the valley lies a proglacial outwash plain which is investigated in the Hidden.Ice project (Helfticht et al. 2023). Beyond investigating the temporal evolution of sediment-rich, proglacial zones through remote sensing datasets, this project expands the monitoring capabilities of the wellestablished Long Term Ecosystem Research Site (LTER) site of the Jamtalferner to build up long-term datasets.

 

  • The Fluchthorn rock slope failure is a significant event that occurred on June 12, 2023. First results of Krautblatter et al. (2024) show a detachment of approximately ~1 million cubic meters of rock from the 3399 meter-high summit resulted in a rock avalanche, which also eroded around 120,000 cubic meters of ice. The findings show the interplay of tectonic, geological pre-failure, and cryospheric factors in shaping the landscape and contributing to such events in mountainous regions impacted by warming climate (Krautblatter et al., 2024).

 

  • On February 23, 1999, an avalanche killed 31 people, which broke loose from the slope north of Galtür below the ridge between Grieskopf and Grieskogel. The avalanche scarp area was located at an altitude of over 2,700 meters, leading to a speed of more than 200 km/h and a cloud of dust of around 100 meters high over a width of 400 meters. More than 300,000 tons of snow were set in motion and partially swept away eleven houses in the main affected district of Winkl (Höller 2007, Turnbull and Bartelt,. 2003, ORF 2024). The month February of 1999 is referred to as an avalanche cycle. The beginning of the year was characterized by a dry and sunny January. However, conditions changed dramatically at the end of January. Three storm periods (January 26 to January 31, February 5 to February 9 and February 17 to February 24) brought more than 2 m of new snow. In Galtür the total height of precipitation in February 1999 was 245 mm, which was about four times as much as the average (Gabl 2000).

 

Tentative time schedule:

Day 1: Thursday, 03.10.2024

  • 08:00 Start from Innsbruck University
  • 09:00 Visit Kühtai: Guided tour at the TIWAG construction site of the hydropower plant
  • 12:00 Lunch break in Oetz / Piburgersee
  • 13:00 Piburgersee
  • 14:00 Habichen rock slide
  • 15:00 Tschirgant rock slide
  • Departure 16:30 drive to Galtür incl. stopover for snacks etc
  • 18:30 Galtür and drive to Jamtal Hütte
  • 19:00 Arrival at Jamtal Hütte; Evening session with focus on regional geology, tectonic setting and map study

Day 2: Friday, 04.10.2024

  • 08:00 Breakfast at the hut
  • 09:00 Hike to the proglacial outwash plain
  • 12:00 Lunch at the hut or at viewpoint
  • 13:00 Hike to the view point Fluchthorn
  • 18:00 Dinner at Jamtal hut

Day 3: Saturday, 05.10.2024

  • 08:00 Breakfast at the hut
  • 09:00 Drive back to Galtür
  • 09:30 visit Avalanche protection/Galtür Museum
  • 12:00 Lunch in Galtür
  • Drive back to Innsbruck

 

Please contact Johannes (Johannes.branke@uibk.ac.at) as soon as possible, but latest by the end of July, if you are interested to join! We can take up to 9 additional students along (full group size of 15). First come, first serve! :) 

 

If you have any questions, please don't hesitate to direct them to Johannes (Johannes.branke@uibk.ac.at) or Simon (Simon.Hinterwirth@student.uibk.ac.at).

We are looking forward to exploring the Tyrolean Oberland together!

 

Your field trip organisation committee, 

Johannes Branke, Simon Hinterwirth, Marcel Ortler, Lotte de Vugt, Clemens Hiller

 

 

 

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