Permafrost: thawing cable car problems.


Some 15 per cent of Switzerland's cable car installations may be at risk of collapse because of rising temperatures as the structures in question are anchored in permafrost--frozen ground that holds many of Switzerland's mountains together.

One solution is to put metal anchors near the foundations to keep the rock firm as the permafrost thaws. Another is to relocate cable car stations, which are in places deemed to be at risk. But a recent study near St Moritz revealed that some areas may be potentially so unstable that even the drastic step of dismantling and rebuilding a station nearby might not be feasible.

Permafrost expert Felix Keller of the Engadine Academy was working in one of the most closely scrutinised permafrost areas in the Alps--the Murtel-Corvatsch region. Temperatures there have been measured since 1987 in a borehole on the rock glacier Murtel.

Between 1987 and 1994, the uppermost 25 metres warmed rapidly by almost a degree...

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