Torrential rainfall in Ramban tehsil, Jammu and Kashmir, has led to severe casualties, extensive infrastructure damage, and mass emergency relocations. Authorities attribute the widespread destruction to a combination of cloudbursts, landslides, and flash floods—natural hazards that frequently devastate Himalayan regions.

What is a Cloudburst?

• Definition:
  A cloudburst is a sudden, extremely intense rainfall event, typically delivering over 10 cm of rain within an hour across a small area (around 10 km²). It often involves hail and thunder and is most common in mountainous terrains, especially the Himalayas.

• Causes:

  • Orographic Lifting: Moist air is forced to ascend over mountain slopes, cooling and condensing to form heavy rainfall. Strong upward air currents allow raindrops to grow larger before they fall abruptly when the currents weaken.

  • Monsoon Dynamics:
    During the Indian monsoon, clouds traveling from the Bay of Bengal or Arabian Sea towards the Himalayas release intense rainfall—up to 75 mm per hour—upon reaching the elevated terrain.

• Notable Incidents:
  Cloudbursts in Himachal Pradesh (2024) and Uttarakhand (2021) triggered fatal floods and landslides, severely damaging infrastructure and causing significant loss of life.

What is a Landslide?

• Definition:
  A landslide is the downward movement of rock, soil, or debris along a slope due to gravity. It is a type of mass wasting where unstable earth materials give way, often catastrophically.

• Causes:

  • Natural Triggers: Heavy rainfall, earthquakes, water seepage, and geological weaknesses in the soil or bedrock.

  • Human-Induced Factors: Deforestation, unplanned construction, and inappropriate land use amplify slope instability.

• Landslide-Prone Areas in India:
  Approximately 0.42 million sq. km (12.6% of India’s landmass) is vulnerable to landslides, with major hotspots in the Northeast Himalayas, Northwest Himalayas, Western Ghats, Konkan Hills, and Eastern Ghats.

• Major Examples:

  • Wayanad, Kerala (2024): Devastating landslides following intense rainfall.

  • Kedarnath Disaster (2013): Over 5,700 fatalities due to landslides and floods.

  • Chamoli, Uttarakhand (2021): A landslide and glacial burst led to severe flooding and loss of life.

What is a Flash Flood?

• Definition:
  Flash floods are rapid surges in water levels, typically developing within six hours of heavy rainfall, and often last for a very short duration. They are highly localized but immensely destructive.

• Causes:

  • Intense Rainfall: When rainfall overwhelms soil absorption capacity and drainage systems.

  • Secondary Triggers:

    • Rapid snowmelt from sudden temperature spikes.

    • Dam or levee failures.

    • Ice or debris jams in rivers.

    • Sudden Glacial Lake Outburst Floods (GLOFs).

  • Urbanization Effects: Impervious surfaces like roads and buildings exacerbate runoff, worsening flood risks.

• Historical Flash Flood Events:

  • Himachal Pradesh (2023): Deadly flash floods caused by cloudburst-driven rain.

  • Uttarakhand (2013): Kedarnath floods linked to cloudbursts and glacial activity.

  • Mumbai (2005): Catastrophic urban flooding due to unprecedented rainfall.