According to the India Meteorological Department (IMD), the weather conditions were triggered by a fresh Western Disturbance over northern and northwestern India.

• There has been an increase in the frequency of Western Disturbances which is directly linked to climate change. 

Western Disturbances (WD)

• Western Disturbances are extratropical storms that are a result of low-pressure areas formed due to the interactions between polar and tropical winds.
  • These are embedded within the subtropical westerly jet stream — a high-altitude, fast-moving air current that flows from west to east in the Earth’s atmosphere — that lies over the Himalayan and Tibetan highlands.
• WD originate in the Caspian Sea or the Mediterranean region and bring sudden winter rain to Hindu Kush, Karakoram, and Western Himalaya region.
• Characteristics:
  • It is a non-monsoonal precipitation pattern which is driven by the westerlies.
  • Most common during the boreal winter (December to March).
  • Results in cold waves, fog, avalanches, landslides, lightning and heavy precipitation.
    • E.g. Uttarakhand Floods in June 2013.
  • Significance: Winter precipitation crucial for water security and agriculture, particularly for the Rabi crops.