Dehradun: A new study by the Indian Institute of Technology (IIT) Roorkee has flagged a fundamental change in the behavior of western disturbances (WDs) – a key weather system driving rainfall and snowfall in the Himalayan region – raising concerns for climate resilience, disaster preparedness and water security in northern India, the institute said in a statement on Wednesday.
The study, published in the International Journal of Climatology, reveals that the Western Disturbance is no longer confined mainly to the winter season. (Representative photo)The study, published in the International Journal of Climatology, reveals that Western Disturbances are no longer mainly confined to the winter season and are now becoming increasingly active in the pre-monsoon months (March to May).
This change, the study warns, significantly increases the risk of flash floods, landslides and extreme rainfall in ecologically fragile mountainous terrain, while also affecting long-term water availability in downstream areas.
Traditionally associated with winter snowfall, WDs now alter the seasonal balance of precipitation across the Himalayas and surrounding regions, showing increasing effects outside the cold season. Researchers have found that WDs are traveling longer distances, depositing more moisture and initiating higher rainfall levels, especially in the Himalayan region.
“Our analysis shows that the Western Disturbance is undergoing significant seasonal and structural changes, especially during the pre-monsoon season. This transformation has far-reaching implications for water resources, extreme weather events and disaster risk in the Himalayas and adjacent regions,” said IIT Roorkee’s principal investigator, Ann Hykology, Department of Ecology.
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The results suggest that climate warming is not only intensifying extreme weather events but also reshaping the timing, structure, and impact of large-scale atmospheric systems.
Analyzing more than seven decades of atmospheric and precipitation data, the researchers identified major changes in WD behavior, including longer travel paths, increased humidity, and stronger upper-level winds—which together increase the intensity of precipitation outside the traditional winter window.
The study emphasizes the urgent need to revise climate models, forecasting frameworks and disaster management strategies, especially for the Himalayan states that are witnessing an increasing frequency of weather-related disasters.
“As a researcher working closely with long-term climate data, it is interesting to see how consistently western disturbances are changing their seasonal role. What we are observing on land today – erratic rainfall and sudden extreme events – clearly reflect these larger atmospheric changes. Extreme events, such as the recent floods, 2025 and Himachal 2025 freezes reflect the increasing impact of these disturbances even during monsoons,” IIT said Spandita Mitra, Ph.D Scholar, Department of Hydrology, Roorkee.
Highlighting the policy relevance of the findings, IIT Roorkee Director KK Pant said, “Scientific evidence is critical for rethinking how we plan for climate resilience in ecologically sensitive regions like the Himalayas. This research reinforces IIT Roorkee’s commitment to directly advance climate policy and is science-ready.”
