New Delhi: IIT Roorkee study flags major shift in western disturbances, warns of flood risks
Dehradun: A new study by the Indian Institute of Technology (IIT) Roorkee has flagged a fundamental shift in the behaviour of Western Disturbances (WDs)—a key weather system driving rainfall and snowfall in the Himalayan region—raising concerns over 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 western disturbances are no longer confined mainly to the winter season and are now becoming increasingly active during the pre-monsoon months (March to May).
This shift, the study warns, significantly increases the risks of flash floods, landslides and extreme rainfall events in the ecologically fragile mountain terrain, while also affecting long-term water availability in downstream regions.
Traditionally associated with winter snowfall, WDs are now showing a growing influence beyond the cold season, altering the seasonal balance of precipitation across the Himalayas and adjoining areas. Researchers found that WDs are travelling longer distances, accumulating more moisture, and triggering higher precipitation levels, particularly in the Himalayan region.
“Our analysis shows that Western Disturbances are undergoing significant seasonal and structural changes, particularly during the pre-monsoon period. This transition has far-reaching implications for water resources, extreme weather events and disaster vulnerability in the Himalayas and adjoining regions,” lead principal investigator from IIT Roorkee’s Hydrology department, Ankit Agarwal, said.
The findings suggest that climate warming is not only intensifying extreme weather events but also reshaping the timing, structure and impact of large-scale atmospheric systems.
By analysing more than seven decades of atmospheric and rainfall data, the researchers identified major changes in WD behaviour, including longer travel pathways, enhanced moisture uptake and stronger upper-level winds—factors that together amplify rainfall intensity outside the traditional winter window.
The study stressed the urgent need to revise climate models, forecasting frameworks and disaster management strategies, especially for Himalayan states that are witnessing a growing frequency of weather-related disasters.
“As a researcher working closely with long-term climate data, it is striking to see how consistently Western Disturbances are changing their seasonal role. What we are observing today on the ground—erratic rainfall and sudden extreme events—clearly reflects these larger atmospheric shifts. Extreme events, such as the 2023 Himachal flood and the recent 2025 Uttarakhand flood, also reflect the growing influence of these disturbances, even during the monsoon season,” PhD scholar at IIT Roorkee’s Hydrology department, Spandita Mitra, said.
Highlighting the policy relevance of the findings, IIT Roorkee director K K Pant said, “Scientific evidence such as this is crucial for rethinking how we plan for climate resilience in ecologically sensitive regions like the Himalayas. This study reinforces IIT Roorkee’s commitment to advancing climate science that directly informs policy and preparedness.”
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