Deadly Himalayan Season Linked to Intensifying Monsoon–Westerly Disturbance Interaction
kathmandu, Nepal – An unusually active monsoon season, coupled with an increasing frequency of westerly disturbances, has contributed to a deadly autumn climbing season in the Himalayas, triggering landslides, flash floods, and unprecedented snowfall.Dozens have been killed in Nepal alone due to monsoon-related disasters over the past week.
The convergence of these weather systems is creating more extreme conditions,experts say.Westerly disturbances – low pressure systems originating in the Mediterranean region that traditionally arrive in northern India,Pakistan,and Nepal between December and March – are now occurring earlier,during the monsoon and autumn months. when these systems meet the warm, wet air of the monsoon, they can “effectively turbocharge the monsoon,” according to Akshay Deoras, a weather scientist at the University of Reading in the UK.
Recent heavy rainfall and snow in eastern Nepal,including the region around Mount Everest in early October,were a direct result of this interaction. Nepal’s meteorology department reported the westerly disturbance fueled a low-pressure system originating from the Bay of bengal, unexpectedly pushing clouds eastward rather of westward.
Scientists have also observed that a warming climate is exacerbating the issue. Warmer air is forcing clouds to higher altitudes,allowing these weather systems to cross the Himalayas and bring increased precipitation to areas like Tibet,which historically experienced a dry climate. A study published in Nature in June noted that the interaction between westerly disturbances and the Indian monsoon is contributing to a shift towards a “warming and wetting climate” on the Qinghai-Tibet Plateau.
this change could lead to unstable weather patterns and more frequent snowstorms and blizzards in Tibet. Logan Talbott, chief guide with Alpenglow Expeditions, which leads climbs on the Tibetan side of Everest, emphasized the need for increased versatility and experienced leadership in the Himalayas. “What’s changed is the reliability of patterns; we can’t assume that conditions will behave the same from season to season,” Talbott said. “That means flexible scheduling, real-time decision-making, and experienced leadership…have become even more vital.”
