Climate Change and the Shifting Patterns of Western Disturbances in India

Western Disturbances are critical weather systems that shape the winter climate of northern India. Traditionally limited to the colder months, they bring much-needed rain and snow, supporting winter crops and replenishing water resources. However, climate change is causing a significant transformation in their frequency, intensity, and timing. The year 2025, particularly, has shown a dramatic shift — with back-to-back disturbances causing unseasonal heavy rainfall, flash floods, and even preventing heatwaves. These shifts are not isolated anomalies but clear indicators of a deeper atmospheric imbalance. This article explores in depth how rising global temperatures are altering Western Disturbances and what it means for India’s climate and agriculture.

What Are Western Disturbances?

• Western Disturbances (WDs) are eastward-moving extra-tropical cyclones that originate over the Mediterranean, Black Sea, and Caspian Sea.
• They gain moisture during their journey over Iran, Afghanistan, and Pakistan before reaching northern India, especially the Himalayan region.
• These systems are embedded in the subtropical westerly jet stream, a fast-flowing ribbon of air that travels west to east at high altitudes.
• WDs are primarily a winter phenomenon, active from December to March, and influence the climate of India, Pakistan, Afghanistan, and Tajikistan.
• Their movement is caused by interactions between polar and tropical air masses, forming low-pressure systems that result in rain and snow.
• In winter, WDs bring rainfall and snowfall essential for the Rabi crops like wheat and barley in states such as Punjab, Haryana, and Uttar Pradesh.
• During summer, they travel at higher latitudes and usually restrict precipitation to upper Himalayan regions, but this pattern is now shifting.

Climate Change and Altering Behaviour of Western Disturbances

• Rising global temperatures are fundamentally altering the behavioural patterns of WDs.
• A 2024 study in the journal Weather and Climate Dynamics found that the frequency of WDs has increased over the last 70 years, especially in the western and central Himalayas.
• Traditionally rare in warmer months, WDs are now appearing in May, June, and July, impacting the usual weather cycles.
• Delayed northward retreat of the subtropical jet stream has contributed to this change, keeping the conditions suitable for WDs beyond their typical season.
• This overlap with the summer monsoon causes unpredictable weather, including extreme rainfall, landslides, and flash floods.
• One of the driving forces behind this change is the strengthening and widening of the subtropical westerly jet stream, fueled by global warming.
• This allows WDs to exhibit more meridional oscillations — enabling them to swing both north and south more than before, increasing the range of their impact.
• According to experts like Prof A P Dimri and Dr K J Ramesh, Arabian Sea warming is also a key factor. Sea Surface Temperatures (SSTs) have increased by 1.2°C to 1.4°C in recent decades.
• This warming results in more moisture being carried by WDs, making rainfall heavier and more intense when they strike.

Extreme Weather Events Triggered by Changing Western Disturbances

• In 2025, back-to-back Western Disturbances caused heavy rainfall, floods, hailstorms, and landslides across several northern Indian states including Jammu & Kashmir, Himachal Pradesh, and Uttarakhand.
• These disturbances also affected Delhi and the surrounding National Capital Region, where gusty winds reaching 80 km/h and torrential rain caused massive waterlogging, disrupted air traffic, and resulted in casualties due to infrastructure collapse.
• The India Meteorological Department (IMD) observed that multiple synoptic systems—including upper air cyclonic circulations—merged over Rajasthan and Madhya Pradesh, intensifying the impact in Delhi.
• Such rare combinations of moisture convergence from the Arabian Sea and the Bay of Bengal, intensified by a favourable tropospheric pattern, are increasing due to changing jet stream behaviour.
• These intensified disturbances are not just causing surface flooding but also uprooting trees, damaging housing structures, and bringing urban life to a halt—especially in megacities like Delhi.
• Apart from North India, unseasonal heavy rains triggered by WDs also impacted Vidarbha, Telangana, and parts of Central India, demonstrating how these events are now affecting wider geographical areas.
• Scientists also noted a rise in snow water equivalent anomaly, indicating unusual snowfall trends in the upper reaches of the Karakoram range and Hindu Kush Himalayas, increasing the risk of avalanches and affecting the glacial mass balance.
• The changes in WDs are thus not just causing more precipitation but altering the timing and intensity of that precipitation, increasing the vulnerability of hilly states to climate disasters.

Impact on Agriculture, Water Security, and the Economy

• Western Disturbances are vital for Rabi crop production, especially in Punjab, Haryana, and western Uttar Pradesh, where winter rainfall ensures adequate soil moisture for crops like wheat and barley.
• Disruption in WD timing, frequency, or intensity can lead to delayed sowing, crop damage due to hailstorms, or even flash floods that erode farmlands, directly hitting agricultural output.
• The late-season WDs also influence kharif crops such as rice and maize, especially when their activities overlap with the monsoon season, resulting in excess rainfall and root rot conditions for crops.
• These changes affect food prices, agricultural planning, and the livelihoods of millions of farmers, making WDs a crucial economic factor.
• Water security is also at stake. WD-induced snowfall feeds into reservoirs and rivers through spring melt, which is essential to bridge the dry gap between the Rabi harvest and the arrival of the monsoon.
• With the shifting WD patterns, this spring meltwater buffer is becoming unreliable, risking urban and rural water shortages.
• The economic impact extends beyond agriculture. Urban flooding, transport delays, and flight disruptions due to WDs significantly affect logistics, supply chains, and commuter safety.
• Cities like Delhi are particularly vulnerable, where inadequate drainage systems fail to cope with even short spells of intense rain.
• Mango orchards and other heat-dependent crops are affected as WDs regulate surface temperatures. The absence of regular heatwaves due to increased WDs in 2025 disrupted fruit ripening cycles, highlighting how changing weather is reshaping India’s agri-economy.

Future Projections and the Need for Adaptation

• Scientists project that Western Disturbances will continue to become more erratic due to persistent global warming, affecting both weather predictability and seasonal cycles.
• As temperatures rise, moisture availability from the Arabian Sea and surrounding regions will increase, making WDs more intense and extending their reach deeper into the subcontinent.
• The broadening of the subtropical westerly jet stream has already allowed WDs to exhibit meridional oscillations, enabling them to travel further north and south than previously recorded.
• This spatial flexibility will lead to more frequent unseasonal rainfall, snow at unusual altitudes, and disruptions in monsoon timing.
• A split in the WD track could lead to disproportionate rain distribution, flooding some areas while leaving others dry, making monsoon predictions less reliable.
• Glacier stability in the Himalayas, already threatened by rising temperatures, may be further compromised by WD-induced snowfall anomalies, leading to glacial lake outburst floods (GLOFs) and increased downstream flooding.
• The increasing unpredictability of WDs also calls for a rethinking of India’s long-term climate planning across sectors such as agriculture, water management, urban infrastructure, and disaster resilience.
• Interdisciplinary research and real-time data sharing between meteorological departments, climate scientists, and policymakers will be critical for adaptive planning.
• Collaboration with neighbouring countries in the Hindu Kush-Himalayan region is also essential, as WDs are transboundary weather systems that require regional cooperation to monitor and manage.

Conclusion

The transformation of Western Disturbances from seasonal weather events into year-round climate disruptors is one of the clearest signs of how deeply climate change is altering India’s atmospheric systems. Their increased frequency, off-season occurrences, and intensified impact are creating challenges that extend far beyond meteorology, influencing everything from agriculture to urban planning. The growing vulnerability of hill states, the prevention of heatwaves, and the disruption of monsoon cycles all point to an urgent need for climate-resilient strategies. Strengthening forecasting systems, redesigning agricultural calendars, and preparing urban infrastructure for sudden rain events must become national priorities. Only with a comprehensive and science-backed approach can India hope to mitigate the cascading risks posed by these evolving weather systems.

Practice Questions (250 words each)

1. How is climate change influencing the frequency and intensity of Western Disturbances, and what are its broader implications on Indian agriculture and food security?
2. In what ways have Western Disturbances started affecting weather patterns beyond their traditional winter influence, and how should urban areas prepare for this shift?