Global Warming - More avalanche threats in Western Himalayas

Rising temperature, presumably due to global warming, has triggered more avalanches in the Western Himalayas in the last 50 years, compared to what used to be the scenario 150 years ago, says a team of European scientists.

Analysing climatic records hidden inside the trees, the researchers found “substantial” increase both in the frequency of the avalanches and their footprint areas, damaging the hills, in Kullu region of Himachal Pradesh.

During the 1990s, avalanches were recorded in most years in Kullu district and in the 2000s, more than 15 events were noted. The largest ones happened in March 2002, March 2003, January 2006 and January 2008.

Archival records highlight similar trends from the nearby areas of Lahaul., Chamba and Kinnaur – all popular tourist destinations.

Many of these avalanches occurred in late winter (or early spring) and wet snow deposits pre-dominated in recent observations, suggesting a substantial shift in snow avalanche activities.

“Recent climate warming is the most plausible explanation for the drastic increase in process activity,” the European researchers reported in a recent issue of the journal Proceedings of the National Academy of Sciences.

Prior to 1970s, snow avalanches were relatively rare. In the 1940s and 1950s, there were hardly any. But there was big jump after the 1970s. Also, the impacted area gets bigger.

The findings contradict the intuitive assumption that warming results in less snow and thus fewer snow avalanches.

The discovery carries major implications for the region that faces increasing population and traffic pressure.

“The findings are not unexpected, but this study probably is the first to provide evidence of what avalanche experts expect to happen in mountain regions and as a result of the climate change,” lead investigator J A Ballesteros Canovas from the University of Geneva told DH.

Canovas with his colleagues from Switzerland, France and Spain reconstructed the climatic history of the Kullu region by analysing the tree rings of 144 trees grown on the slopes.

As the growth of a tree varies with local weather for a long time, the climate leaves a long-lasting imprint inside the woods that can be studied later to understand past climate patterns.

This the technique that the European team employed to reconstruct the avalanche trends in the Western Himalayas since the last 150 years.

So is there a marked increase in avalanches in the last 20 years, which is the warmest in the history of mankind? “I can confirm that this increase is observed at the site we analyzed. However, a full picture about the Himalayas will come only with more investigation and research,” said Canovas.