Seven-decade analysis shows Western Disturbances intensifying beyond winter, raising flood risks, landslides, and water security concerns across northern India.
A new study by the Indian Institute of Technology (IIT) Roorkee has identified a significant shift in the behaviour of Western Disturbances (WDs), the key weather systems responsible for winter rainfall and snowfall across northern India and the Himalayas. The findings raise fresh concerns about climate resilience, disaster preparedness and long-term water security in the region.
Published in the International Journal of Climatology, the research highlights how Western Disturbances — traditionally associated with winter precipitation — are now becoming increasingly active during the pre-monsoon months. Scientists say this seasonal shift is altering the distribution and intensity of rainfall across the Himalayan belt and adjoining plains.
Rising Pre-Monsoon Activity
According to the study, Western Disturbances are travelling longer distances and accumulating greater moisture before reaching the Indian subcontinent. This has led to a noticeable rise in rainfall during the March to May period, a time previously less dominated by these systems.
Researchers analysed more than 70 years of atmospheric and rainfall data to detect structural and behavioural changes in WD pathways. The findings show enhanced moisture uptake, stronger upper-level winds and longer travel trajectories — factors that together amplify rainfall intensity beyond the traditional winter season.
This evolving pattern significantly increases the risk of flash floods, landslides and extreme rainfall events in the fragile Himalayan terrain. It also has implications for downstream water availability, agriculture and hydropower systems.
Link to Recent Extreme Events
Spandita Mitra, PhD Scholar in the Department of Hydrology at IIT Roorkee, said the shift in seasonal behaviour is clearly visible on the ground.
“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 — erratic rainfall and sudden extreme events — reflects these larger atmospheric shifts. Events such as the 2023 Himachal flood and the 2025 Uttarakhand flood also demonstrate the growing influence of these disturbances, even during the monsoon season,” she said.
Lead Principal Investigator Prof. Ankit Agarwal noted that the transformation of Western Disturbances during the pre-monsoon period has far-reaching consequences.
“Our analysis shows significant seasonal and structural changes in Western Disturbances, particularly during March to May. This transition has serious implications for water resources, extreme weather events and disaster vulnerability in the Himalayas and adjoining regions,” he said.
Implications for Climate Policy and Preparedness
The study underscores the need to update climate models, forecasting systems and disaster management strategies in light of these emerging trends. Himalayan states, already prone to landslides and cloudbursts, may face increasing vulnerability as warming temperatures reshape atmospheric circulation patterns.
IIT Roorkee Director Prof. K.K. Pant emphasised the policy relevance of such scientific findings.
“Scientific evidence like this is crucial for rethinking climate resilience planning in ecologically sensitive regions such as the Himalayas. Institutions must play a proactive role in translating scientific insights into actionable strategies for sustainable development and disaster preparedness,” he said.
Call for Dynamic Forecasting and Risk Assessment
The researchers stressed that adapting to the changing behaviour of Western Disturbances will require coordinated efforts across scientific institutions, governance systems and infrastructure planning agencies. They have called for dynamic forecasting frameworks and region-specific risk assessments to better safeguard lives, livelihoods and ecosystems.
As climate change accelerates, the evolving nature of Western Disturbances could redefine seasonal rainfall patterns across northern India, making proactive planning essential for reducing future disaster risks and ensuring long-term water security.