Landslide Disasters in Schnann
Schnanner Creek – a wild torrent since the beginning of time – originates in the southern slopes of the Vorderseespitze Peak and has a drainage basin (watershed) area of 6.50 km². The bedrock of the drainage basin is principally Dolomite rock with a covering of natural slate, which is washed down the gorge during exceptionally strong storms. Without this gorge, which is also a geological attraction, Schann could never have been built where it is now. The first two dams were constructed in 1934 and the years that followed – the first is circa 250 metres behind the gorge, the second approx. 90 minutes’ walk towards Alperschon. Massive landslides have always been an issue – occurring, for example, in 1852, 1876, 1906, 1934, 1944, 1952 and 1969. Under the direction of HR Dr. Leys (WLV Tirol), a protective wall was built on the Schnann from 1979-1980 – in the hope that our village would remain spared from future landslide disasters. The hopes of the Schanner folk were only to be partially fulfilled, as the following chronology shows. The Schanner Creek refuses to be tamed and has run riot a number of times since. Despite completed defence installations, it remains faster and more dangerous than ever before.
17th September 1986: Heavy mudslide after a severe thunderstorm in the Lechtal Alps. The river flow is impeded by avalanche wood in the upper reaches of the stream. 15.000 m³ of hard material is washed down to the valley. The Rosanna River is blocked along a 300m stretch.
29th July 1990: Severe landslide after a hailstorm in the „Hinteren Pleisen“. 25.000 m³of scree and rock are washed by the Schanner down to the valley, ravaging the entire village centre. 12 residential buildings, 2 small businesses and around 800 metres of local roads were swallowed by the slide. Cultivated lands, supply and disposal pipes were also severely affected. Damages in Schann alone amounted to circa EUR 300,000. The bridge over the gorge was swept away and ended up wedged in the lower reaches of the Schnanner Creek.
23rd October 1990: The presentation of the „Schanner Gorge Mudslide Barrier“ project was attended by many Schann residents. The entire construction consists of five phases: road building – tunnelling – filling of the avalanche catchment dam in Althaus – rebuilding of the community bridge –sediment dam with a capacity of 48.000 m³.
February - March 1991: During tunnel construction three misfired blasts not only severely damaged the underlying houses, several residents were also injured.
8th August 1991: Landslide after a hailstorm. Ca. 5.000 m³ of stone ended up below the village bridge. The children’s playground was severely damaged again.
7th August 1992: Landslide near Samspitze after a hailstorm. Another landslide from „Gassli“ occurred almost simultaneously, stifling the Rosanna water-flow and causing a huge backlog of water. An „unfavourable“ moon phase meant that the landslide also ripped open deep holes. The newly constructed sediment dam prevented a major disaster. Will the sediment dam continue to deliver this promise in the future?
18th August 2002: The „Bergacker-Chapel of St. Michael“, built by the „Schann Chapel Community“ under the guidance of their initiator, Gebhard Zangerl, is consecrated. St Michael is the patron saint against lightning, hail, storms and severe weather.
23rd August 2005: Prolonged and intense rainfall (it rained continuously for 14 days) triggered the greatest landslide disaster in living memory, not only in Schann and its surrounding communities, but throughout the entire Landeck district on the night of the 23rd and 24th August.
1st August 2018: A thunderstorm with heavy rain and hail in the area of Gridlontobel and Schnanner Klamm triggered a large mudslide within a very short time. Within 5 to 10 minutes, the retention basin was filled with about 80,000 m³ of material, and the rest thundered with enormous force and high speed over the retaining wall through the Schnanner stream, thereby clogging the Rosanna. The river became dammed with the debris and the water flooded the surrounding fields and almost the entire industrial area in Schnann. There was great damage to the infrastructure of the municipality and to the businesses in the industrial area.
To this day, the rumble and roar of the Schanner Creek during a thunderstorm gives rise to a sense of unease amongst the Schanner folk.