Western Disturbances

News- Recently, heavy rain and strong winds lashed Delhi and nearby areas, causing waterlogging and flight delays at the airport. The weather was triggered by a fresh Western Disturbance over northern India.

About Western Disturbances

• Definition– Western Disturbances are eastward-moving, extra-tropical weather systems that bring sudden winter rainfall to the northwestern parts of the Indian subcontinent.These disturbances originate beyond Iran and Afghanistan and travel across these countries, as well as Pakistan, before reaching India.
• Origin and Characteristics:
  • They are driven by low-pressure systems that form due to the interaction of polar and tropical air masses.
  • These systems pick up moisture from the Mediterranean Sea, Black Sea, Caspian Sea, and occasionally the Arabian Sea.
  • They are embedded in the Subtropical Westerly Jet Stream (STWJ), which flows from west to east at high altitudes over the Himalayas and Tibetan Plateau.
• Seasonal occurrence: Most active during the boreal winter months (December to March), but can also affect weather patterns during the pre-monsoon and post-monsoon periods.
• Geographical impact:
  • Affect weather in northwestern India, northern Pakistan, parts of Afghanistan, and Tajikistan.
  • In India, they bring winter rainfall to states like Punjab, Haryana, Rajasthan, Himachal Pradesh, Uttarakhand, and parts of Uttar Pradesh.
  • Often responsible for snowfall in the Himalayas and cold wave conditions in the plains.
• Importance for Agriculture:
  • Beneficial for Rabi crops, especially wheat, by providing much-needed winter rainfall.
  • However, excessive rainfall or untimely storms can damage standing crops and disrupt normal life