Cloudburst

Five children among seven killed in cloudburst, landslide in Kathua.

Cloudbursts in India: Causes, Consequences, and Preparedness

Definition and Characteristics

• Nature of Event: A cloudburst is a sudden and highly intense rainfall event (?100 mm/hour over 20–30 km²).
• Cloud Source: Typically originates in cumulonimbus clouds between 1000–2500 m altitude under unstable, moisture-rich conditions.
• Langmuir Effect: Raindrops grow through coalescence until gravitational pull overcomes updrafts, leading to a sudden downpour.

Climatological and Geophysical Mechanisms

• Orographic Uplift: Moist air is forced upwards by hills, condensing rapidly into dense clouds.
• Airmass Convergence: Interaction of monsoon winds with dry air enhances vertical uplift.
• Instability and Low Pressure: Sudden temperature/pressure changes and regional depressions accelerate condensation.
• High Humidity and Lightning Delay: Excess moisture retention within clouds magnifies precipitation intensity.

Cloudburst-Prone Regions in India

• Himalayan States: Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Sikkim.
• North-East India: Arunachal Pradesh, Meghalaya, Nagaland.
• Western Ghats: Kerala and Karnataka occasionally report such events.

Recent Examples

• Cloudburst-triggered Flash Flood in Chositi, Kishtwar (August 2025)
• Uttarkashi Flash Floods Following Cloudburst (5 August 2025)
• Mandi, Himachal Pradesh (July–August 2025)
• Himachal Pradesh (Kullu, August 2023)
• Uttarakhand (Rudraprayag, July 2023)
• Amarnath Yatra (J&K, July 2022)
• Ladakh (Leh, August 2010)

Hazards Associated with Cloudbursts

• Flash Floods: Torrents sweep away settlements, roads, and bridges in valleys.
• Landslides and Mudflows: Water-saturated slopes collapse, generating destructive slurry flows.
• Ground Subsidence: Excess pressure leads to sinkholes and hillside collapses.
• River System Impact: Riverbank erosion, course shifts, and temporary landslide lakes increase downstream flood risks.

Climate Change and Increasing Cloudburst Frequency

• Enhanced Atmospheric Moisture: Warmer air holds more water vapour, causing intense rainfall.
• Erratic Monsoon Patterns: Shorter, more intense rainfall episodes replace steady monsoon rains.
• Himalayan Vulnerability: Steep topography, fragile geology, and unplanned construction amplify disaster risks.

NDMA Guidelines on Cloudbursts

• Risk Mapping: GIS-based identification of hazard-prone zones.
• Radar Coverage Expansion: Installation of Doppler radars in vulnerable hill districts.
• Urban Drainage Planning: Design stormwater drains for short-duration high-intensity rainfall.
• Community Preparedness: Conduct mock drills, awareness campaigns, and early warning dissemination via SMS and sirens.
• Construction Regulation: Enforce slope-based building controls through micro-zoning techniques.

Way Forward

• Improved Prediction Systems: Adoption of high-resolution weather models and AI-based forecasting for localised rainfall.
• Strengthened Early Warning Mechanisms: Real-time monitoring networks in Himalayan States with siren/satellite-based alerts.
• Eco-sensitive Infrastructure: Restriction of construction in fragile slope zones, mandatory slope-stabilisation measures, and watershed management.
• Reforestation and Land Use Regulation: Afforestation to stabilise slopes and better land regulation to prevent unplanned expansion.
• Community Resilience: Training locals in evacuation, first aid, and relief operations to minimise casualties.