A large chunk of ice broke loose Sunday afternoon, triggering an ice-debris avalanche roaring down … [+]
A large chunk of ice broke loose Sunday afternoon, triggering an ice-debris avalanche roaring down the Marmolada glacier in the Dolomites, Italy. Ice fragments and boulders struck a popular hiking trail, killing at least six and injuring 14. According to authorities, 20 people are reported missing.
The disaster struck after a month of warm weather and one day after a record-high temperature of 10 degrees Celsius (50 degrees Fahrenheit) was recorded at the mountain’s summit.
Rising temperatures have become a major cause of concern when it comes to landslides, avalanches and rock-fall incidents in mountains.
In 2016, geomorphologist and mountaineer Arnaud J.A.M. Temme used old guidebooks to reconstruct rock-fall activity along popular hiking and climbing routes.
The research focused on the percieved risk of routes on five mountains in the Eiger region (Swiss Alps). In 69 cases (19 percent of all studied routes) an increased risk of sudden rock-fall, as the rocks were described by experienced climbers to be more brittle, was noted. This trend by climbers to perceive cliffs as more unstable was especially strong in the last few decades. The most recent guidebooks also removed seven of the surveyed routes, claiming they were too dangerous.
For large landslides, the trend is not so clear.
In 2008, researchers at the University of Innsbruck reviewed the available ages of landslides and debris flows in the Central Alps. Their database, even if not complete, covers a timespan of 10,000 years. They found indications of a clustering of large mass movements during the Subboreal, a period 4,200 to 3,000 years ago characterized by a warm and wet climate.
Rising temperatures cause glaciers to shrink and frozen soil to thaw. As a result, mountain slopes are quickly losing support and the “icy” glue keeping them together. Water enters the rocks through the now open fissures, acting as a lubricant and causing huge blocks of rock or ice to slip – gravity will do the rest.
