Glacier collapse believed to have triggered massive mudslide in Nepal

A collapsing glacier and a landslide are likely to have triggered the mudslide disaster in Nepal. This type of flash flood has become more common as a result of global warming, according to Mats Eriksson at the Swedish Geotechnical Institute.

´We will undoubtedly experience more similar events in the future,´ he says. Large sections of a glacier break away and plunge down a steep mountainside. As it falls, it sweeps up boulders, rocks, gravel and soil.

The immense energy of the growing mass generates heat that melts ice into water, which mixes with the slurry-like mass of rocks, earth, debris and mud. The torrent sweeps away terrain, houses, roads and bridges along the valley. This is the presumed sequence of events that led to the loss of hundreds, maybe thousands, of lives and the destruction of villages, towns and infrastructure in Nepal on the slopes of the Himalayas on Wednesday, according to the US Geological Survey (USGS).

Such events occur at regular intervals and have probably increased in scale in line with global warming, which is causing glaciers to retreat, become unstable and lose mass, says Mats Eriksson, head of department at the Swedish Geotechnical Institute.

Risk in mountainous areas

This, in turn, creates more glacial lakes in the mountains, which are dammed up behind unstable ridges – moraine ridges in the valley. If these break, powerful flood waves are created that can sweep entire villages away in a devastating mudslide.

´We will most certainly experience more similar events in the future,’ says Mats Eriksson.

Other experts and researchers also see a link between floods such as the one in Nepal on Wednesday and global warming.

Dorothy Heinrich, a meteorology researcher at the University of Reading in the UK, told the AFP news agency that climate change tends to manifest itself in the form of disasters of this kind. According to Mats Eriksson, there is a risk of similar floods anywhere in mountainous regions with glaciers, such as the Alps, the Himalayas and the Andes.

Keep an eye on the glaciers

How, then, can people protect themselves against such disasters? It is important to keep a close eye on how glaciers are retreating, according to Mats Eriksson.

´In rugged terrain, satellite imagery and field visits can be used to monitor glacial retreat,´ he says.