A rise in global temperatures is triggering avalanches, leading to disasters and other serious consequences in mountain areas. According to results of a study undertaken by University of Geneva researchers, rising temperatures are increasing the frequency, size, and scope of avalanches in Western Himalayas. This can have a severe impact on socio-economic development and cause the destruction of road infrastructure in the region, the study says.
The study, which has been published in the international journal Proceedings of the National Academy of Sciences, took place between 2013 and 2015 in the Himachal Pradesh state of India, which is at an elevation of approximately 3,000 meters.
The researchers made use of data records as well as a scientific method called dendrochronology, which is the study of counting tree rings to determine their age, enabling researchers to trace the extent and impact of avalanches in the region since 1855.
This tree-ring-based snow avalanche reconstruction showed an increase in occurrence and runout distances of avalanches in recent decades. Statistical modeling suggests that this increase in avalanche activity is linked to climate warming that is taking place at the same time.
This technique allowed researchers to trace 38 avalanches over the period of the study, which is “the largest survey conducted to date in the Himalayas.” By combining their findings from the trees with local climate data, the researchers found an upward trend in the frequency and intensity of avalanches in the second half of the 20th century.
According to the findings of the study, “Avalanches are bigger, travel greater distances, and are triggered earlier in the year. These changes can be attributed clearly to rising temperatures, which have reached 0.2 to 0.4 degrees annually in some parts of the Himalayas.”
The study also suggests that various specific triggers related to warmer air temperatures, such as receding glaciers, melting permafrost, rain falling on snow, and snowfall that starts earlier in the year and becomes destabilized before spring, are causing the upward trend.
Scientists say that this contradicts the intuitive assumption that climate warming would result in less snow, and, therefore, fewer snow avalanches in the region.
The study has major implications for disaster risk management and risk mitigation in the Western Himalayan region where human settlements are steadily increasing and there is increasing traffic on a steadily expanding road network. This calls for an immediate design of risk mitigation strategies to enhance climate change adaptation in the region.
The Himalayas are inhabited by roughly 52.7 million people and the range is spread across five countries: Pakistan, India, Nepal, Bhutan, and China. As recent as 2017, heavy snow and avalanches in northern Pakistan resulted in at least 14 deaths, including nine in Chitral district alone.