Cloudbursts in Himachal Pradesh

On July 2025, ten cloudbursts, three flash floods, and a landslip struck various parts of Mandi district in Himachal Pradesh, resulting in 13 confirmed deaths and 29 people still missing, as of July 3. Rescue operations continue across the Gohar, Thunag, and Karsog subdivisions.

Cloud Burst:

• A cloudburst is defined by the India Meteorological Department (IMD) as an extreme weather event characterized by more than 10 cm of rainfall within one hour over an area of approximately 10 square kilometers.
• These events are localized, highly intense, and usually occur with minimal or no prior warning.
• Cloudbursts are commonly associated with thunderstorms, lightning, and hail, and are most frequently observed in mountainous regions, particularly the Himalayan belt.

Causative Factors

• Orographic Lifting: Moist monsoonal winds are forced upwards along mountain slopes, leading to rapid cooling and condensation, resulting in torrential precipitation.
• Strong Convective Currents: Upward air currents suspend raindrops in the atmosphere, allowing them to accumulate. A sudden weakening of these currents results in the abrupt release of accumulated water.
• Monsoon Dynamics: As monsoon clouds from the Bay of Bengal or Arabian Sea move northward and encounter the Himalayas, they release significant amounts of rainfall in a short span of time.
• Complex Topography: The irregular terrain of the Himalayan region further amplifies localized convective activity.

Distinction Between Cloudbursts and Normal Rainfall

• Unlike normal rainfall, a cloudburst is:
  • Intensely concentrated in both time and space.
  • Sudden and highly destructive, often resulting in flash floods and landslides.
  • Difficult to forecast due to its micro-scale nature.

Vulnerable Regions in India

• Western Himalayas: Jammu & Kashmir, Himachal Pradesh, Uttarakhand.
• Eastern Himalayas: Sikkim, Arunachal Pradesh.
• Western Ghats: Kerala, Karnataka.
• Northeastern Hills: Nagaland, Manipur, Mizoram.

Notable Incidents

• Uttarakhand (July 2021): Cloudbursts in Chamoli, Uttarkashi, and Pithoragarh led to extensive flash flooding, landslides, and loss of life and infrastructure.
• Himachal Pradesh (August 2020): Cloudbursts in Kullu, Lahaul-Spiti, and Kinnaur triggered severe landslides and washed away roads and bridges.
• Himachal Pradesh (August 2025):Cloudbursts in Mandi and Kullu

Consequences

• Flash Floods: Rapid and localized rise in water levels, typically occurring within 3 to 6 hours of rainfall.
• Landslides: Triggered by saturation of soil, leading to mass movement of debris, particularly in unstable hilly terrain.
• Mudflows: Dense and high-viscosity flows of water mixed with silt and sediment; capable of causing irreversible geomorphological changes.
• Human and Economic Losses: Displacement of communities, loss of lives, destruction of roads, bridges, and agricultural land.

Mitigation and Risk Reduction Strategies

• Early Warning Systems: Deployment of Doppler weather radars and satellite-based real-time monitoring to improve short-term forecasting.
• Urban Planning: Development of efficient stormwater drainage systems, flood-resistant infrastructure, and regulated land use.
• Watershed and Slope Management: Afforestation, check dams, terracing, and soil conservation techniques to reduce runoff and erosion.
• Public Awareness and Training: Community-level education and emergency preparedness drills in high-risk zones.
• Policy and Regulation: Enforcement of construction norms in ecologically sensitive zones and mandatory environmental impact assessments.
• International Collaboration: Sharing of hydrometeorological data, technology transfer, and regional cooperation in Himalayan disaster management.