Western Disturbances

Recently Delhi and surrounding areas experienced heavy rainfall and strong winds caused by a Western Disturbance, disrupting flights and causing waterlogging.

Experts attribute the increasing frequency and intensity of such disturbances to climate change and global warming.
States like Himachal Pradesh, Uttarakhand, and Jammu & Kashmir faced flash floods and landslides due to intense Western Disturbances in March and April 2025.

What Are Western Disturbances?

Western Disturbances

Western Disturbances are extra-tropical low-pressure systems originating near the Mediterranean region.
They move eastward, carried by the subtropical westerly jet stream towards the Indian subcontinent.
These disturbances bring rainfall in plains and snowfall in the Himalayan region, particularly during winter (December to February).
Unlike monsoon systems, they carry moisture in the upper layers of the atmosphere.
They are crucial for winter rainfall and snowfall over northwest India and the western Himalayas.

Impact of Western Disturbances

Climate and Weather Influence: Western Disturbances bring essential winter rainfall to northwestern India, causing temperature drops, cold waves, and widespread fog, while also occasionally triggering extreme weather beyond winter.
Agricultural Significance: These systems support rabi crop (such as wheat ) growth by providing winter precipitation and preserving soil moisture, but excessive or unseasonal rains can harm crops and delay sowing.
Hailstorm and Crop Damage: Strong Western Disturbances may lead to hailstorms, which can severely damage orchards and vegetable crops across affected regions.
Glacial and River System Support: Snowfall from Western Disturbances nourishes Himalayan glaciers, maintaining steady flows in rivers like the Ganga and Indus during dry periods.
Impact on Water Resources: Rainfall and snowmelt from these systems replenish groundwater, fill reservoirs, and support irrigation, though intense events can lead to floods and landslides.

Changing Pattern of Western Disturbances

Traditionally limited to winter, Western Disturbances now occur more frequently in non-winter months like May, June, and July.
Their influence has expanded beyond the western Himalayas to include central and eastern parts of the range.
In recent decades, they have caused extreme rainfall, floods, and landslides during spring and early summer.
Their presence in pre-monsoon periods can disrupt monsoon onset and agricultural calendars.
They are now more intense, widespread, and erratic in behavior compared to earlier decades.

Factors Responsible for Changing Pattern

Rising Temperatures and Stronger Disturbances: Global warming has intensified the subtropical westerly jet stream, making Western Disturbances stronger and more frequent due to enhanced air mass interactions.
Arabian Sea Warming: Sea surface temperatures in the Arabian Sea have increased by 1.2–1.4°C, adding more moisture to Western Disturbances and increasing their year-round intensity.
Enhanced Jet Stream Activity: A stronger and warmer upper atmosphere has broadened the jet stream, allowing Western Disturbances to travel farther and stay active longer.
Shifting Disturbance Paths: Western Disturbances now show more north-south movement, deviating from traditional paths due to increased meridional jet stream oscillations.
Delayed Jet Stream Retreat: A slower retreat of the subtropical jet delays the monsoon, causing Western Disturbances to overlap with monsoon systems and raising the risk of extreme weather.
Moisture Availability: Continuous moisture feeding from the Mediterranean, Caspian Sea, and increasingly, the Arabian Sea, sustains disturbances even outside the winter.
- This leads to more off-season rainfall and increases unpredictability in weather patterns.

Conclusion

The changing pattern and increasing frequency of Western Disturbances are clear indicators of climate change impacts on regional weather systems.
While they remain vital for winter rainfall and agriculture in northwest India, their intensification and irregularity pose new challenges.
Understanding and adapting to these evolving patterns is crucial for climate resilience, disaster preparedness, and sustainable agriculture in the region.

Western Disturbances Vs Monsoon

Aspect	Western Disturbances	Monsoon (Southwest)
Introduction	Western Disturbances are extra-tropical weather systems bringing winter rain and snow to northwestern India.	The monsoon is a seasonal tropical wind system bringing widespread rainfall to most parts of India during summer.
Origin	They originate near the Mediterranean Sea and move eastward.	They originate due to differential heating of land and sea, primarily influenced by the Indian Ocean.
Type of System	They are low-pressure systems formed in the mid-latitudes.	They are tropical systems driven by thermal pressure differences and ocean-atmosphere interactions.
Season/Months	Predominantly active during winter (December to February), but increasingly seen in pre-monsoon months.	Active mainly from June to September during the southwest monsoon season. Retreating Monsoon Season during October and November which causes rain in the eastern part of the Peninsula.
Moisture Source	They draw moisture from the Mediterranean, Caspian Sea, and Arabian Sea.	They collect moisture while crossing the warm Indian Ocean and the Bay of Bengal.
Main Impact Area	Affect northwest India and the western Himalayas.	Impact almost all of India, especially central, western, and northeastern regions.
Associated Phenomena	Cause snowfall, winter rain, fog, and cold waves.	Bring widespread rain, floods, soil erosion, and break periods.
Influencing Factors	Influenced by the subtropical westerly jet stream.	Influenced by Inter Tropical Convergence Zone (ITCZ), sea surface temperature, Tibetan heating, and jet streams.

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