New Delhi: Indian Institute of Technology Roorkee has identified a significant transformation in the behaviour of Western Disturbances (WDs), the key weather systems that influence rainfall and snowfall across northern India and the Himalayan region.
The findings, published in the International Journal of Climatology, point to growing climate-related risks for disaster preparedness, water security, and ecological stability in the region.
Traditionally associated with winter snowfall, Western Disturbances are now increasingly active during the pre-monsoon months, particularly between March and May.
According to the study, climate warming is not only intensifying extreme weather events but also reshaping the timing, structure, and seasonal impact of these large-scale atmospheric systems.
By analysing over 70 years of atmospheric and rainfall data, researchers observed marked structural and behavioural changes in WD pathways. These systems are now travelling longer distances, accumulating greater moisture, and exhibiting stronger upper-level winds before reaching the Indian subcontinent.
As a result, precipitation linked to Western Disturbances is rising during the pre-monsoon period , a shift that significantly heightens the risk of flash floods, landslides, and extreme rainfall events in the fragile Himalayan terrain. The altered seasonal pattern could also disrupt long-term water availability in downstream regions dependent on snowmelt and regulated river flows.
“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 on the ground today 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,” said Spandita Mitra, PhD Scholar, Department of Hydrology, IIT Roorkee.
Lead Principal Investigator Prof. Ankit Agarwal noted that the findings demand urgent attention from policymakers and climate scientists alike.
“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,” he said.
The researchers argue that existing climate models and forecasting frameworks must be revisited to account for these evolving patterns. Himalayan states, already experiencing a rising frequency of weather-related disasters, may need to recalibrate disaster management strategies and infrastructure planning to address shifting risk windows.
Prof. K.K. Pant, Director of IIT Roorkee, emphasised the broader significance of the research. “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. As climate change accelerates, institutions must play a proactive role in translating scientific insights into actionable strategies for sustainable development and disaster resilience,” he said.
The study underscores the need for integrated efforts across science, governance, and infrastructure development to adapt to evolving weather systems. With Western Disturbances continuing to shift under a warming climate, the researchers call for dynamic forecasting frameworks and region-specific risk assessments to safeguard lives, livelihoods, and critical ecosystems across northern India.
As climate patterns grow increasingly unpredictable, the findings serve as a warning that long-established seasonal assumptions may no longer hold, and that resilience planning must evolve just as rapidly as the atmosphere itself.
