Global warming raising the risk of avalanches

UNIGE researchers confirm a direct link between global warming and the growing frequency and intensity of avalanches. How? By analysing tree rings in the Himalayas.

General view of the snow avalanche slopes at Dhundi, Himachal Pradesh, India. (Juan Antonio Ballesteros-Cánovas / UNIGE)
General view of the snow avalanche slopes at Dhundi, Himachal Pradesh, India. (Juan Antonio Ballesteros-Cánovas / UNIGE)

The effects of a dangerous global warming are felt particularly in mountains regions, where the ascent in temperatures is better than expected, influencing both glacierized scenes and water resources. The repercussions of these progressions are complex and fluctuated, from withdrawing icy masses to an expansion in the recurrence and power of snow torrential slides.

A group of specialists from the University of Geneva (UNIGE), Switzerland, has utilized dendrochronology– the remaking of past debacles as recorded in development arrangement of trees–  to disentangle the role of global warming in the triggering avalanches.

Avalanches are a natural phenomenon and occur repeatedly in mountain areas; nonetheless, rising temperatures are altering their triggering. This can prompt disasters and genuine outcomes in mountain regions where they can extremely influence the financial advancement and the demolition of traffic infrastructure and buildings. This is the situation in the Indian province of Himachal Pradesh, where expanding private numbers and tourism are applying weight ashore utilize.

Along the street to Leh, 500 km north of New Delhi, the Indian government has begun to bore one of the biggest passages of the Indian sub-mainland. With the continuous atmosphere warming, the frontage road to the passage is ending up progressively debilitated by snow torrential slides. This is the reason UNIGE analysts led their hands-on work at the spot from 2013 to 2015, in a valley situated at in the vicinity of 3,000 and 4,000 m.

The aim of the research group was to evaluate – and add to – the information currently available about avalanches with two goals: i. to identify the nature of the changes in avalanche activity currently taking place; and ii. to assess future needs for tackling these changes. In the absence of data comparable to the information collected in European surveys, for which records often exist for the past few centuries, the UNIGE researchers focused on trees: they examined stumps (when the tree had been removed) or cored trees that were still standing to reconstruct past snow avalanches at the study site.

Juan Antonio Ballesteros-Cánovas, a senior lecturer at UNIGE’s Institute for Environmental Sciences said, “Since we knew the position of each affected tree, we were able to reconstruct the dynamics, lateral extent and runout distance of every avalanche. This technique meant we could go back to 1855 and record 38 avalanches over this period in the valley, the largest survey conducted to date in the Himalayas.”

The models utilized for testing the effect of environmental change consolidate the dangers of torrential slide with nearby atmosphere information. They were changed in accordance with incorporate the reasonable impact on geological highlights coming about because of prior torrential slides. Since they devastate the plant cover, they are a disturbing danger factor. The outcomes brooked no contention: from the second 50% of the twentieth century, there has been an expansion in the quantity of torrential slides, both as far as recurrence and power. The recurrence has ascended from one occasion for each decade to just about one occasion each year.

The research was being carried out within the framework of the Indian Himalayas Climate Adaptation Program (IHCAP), a partnership led jointly by the Indian and Swiss authorities with strong scientific input from UNIGE.

The results of this study are published in the Proceedings of the National Academic of Science – PNAS.