Avalanche

Syllabus: Disaster Management

Source:  IE

Context: A massive avalanche struck a BRO project site near Mana village in Chamoli district, Uttarakhand, trapping 22 workers under ice, with ongoing rescue operations by the Indian Army and ITBP.

About Avalanche:

What is an Avalanche?

• A sudden and rapid descent of snow, ice, and debris down a mountain slope, triggered by natural or human-induced factors.
• Can cause widespread destruction by burying people, structures, and transport routes under tons of snow.

Types of Avalanches:

1. Loose Snow Avalanche:
   • Forms when loosely bonded snow starts sliding from a single point.
   • Common in steep slopes (>40°) with fresh snowfall.
2. Slab Avalanche:
   • Occurs when a cohesive layer of snow breaks away as a single slab.
   • Responsible for most fatalities, reaching speeds of 100 km/h.
3. Gliding Avalanche:
   • Involves entire snowpack sliding over a smooth surface (grass, rock).
   • Occurs at slopes >15° and leads to large-scale destruction.
4. Powder Avalanche:
   • High-speed avalanches suspending snow particles in air, creating a powder cloud.
   • Can reach speeds of 300 km/h, causing severe shockwave impact.
5. Wet Snow Avalanche
   • Triggered by melting snow due to temperature rise or rain.
   • Slower but more destructive due to its high density and force.

Causes of Avalanches

1. Natural Causes:

• Heavy Snowfall & Wind Direction: Unstable snowpack due to uneven accumulation.
• Steep Slopes: Avalanches commonly occur at 30°-45° inclinations.
• Temperature Fluctuations: Melting snow weakens internal layers, increasing instability.
• Earthquakes & Vibrations: Trigger snow movement on unstable slopes.

2. Human-Induced Causes:

• Winter Sports & Tourism: Skiing, snowmobiling, and trekking destabilize snow layers.
• Construction & Deforestation: Removal of trees weakens slope stability.
• Military Operations: High-altitude warfare and detonations can trigger slides.

Consequences & Impact of Avalanches:

• Loss of Life & Injuries: Avalanches cause suffocation, hypothermia, and fatal trauma, with survival chances dropping significantly after 15 minutes of burial.
• Destruction of Infrastructure: Snow slides block roads, railways, and highways, cutting off access and burying homes, BRO camps, and tourist shelters under heavy snow.
• Disruptions in Communication & Utilities: Avalanches damage power lines, water supply, and communication networks, delaying rescue operations and emergency responses.
• Environmental Hazards: Melting avalanche snow can trigger landslides and flash floods, leading to severe ecological damage and displacement of local communities.
• Economic Impact: Avalanches cripple winter tourism, disrupt livelihoods, and result in economic losses, requiring huge recovery costs for damaged infrastructure and services.

Precautionary & Control Strategies:

1. Avalanche Early Warning Systems:

• IMD Avalanche Forecasting: Tracks snowfall, slope stability, and temperature fluctuations.
• Remote Sensing & AI-Based Prediction Models: Used for real-time avalanche detection.

2. Structural Protection Measures:

• Snow Barriers & Fences: Installed on avalanche-prone slopes to prevent snow buildup.
• Deflecting Structures: Direct the avalanche path away from inhabited zones.

3. Artificial Avalanche Triggers:

• Controlled Explosions: Initiates small avalanches to prevent larger, unmanageable ones.

4. Zoning & Land Use Planning

• Avoidance of Construction in Avalanche-Prone Areas.
• Ski Resorts & Highways Must Follow Risk Assessment Reports.

Way Ahead:

1. Enhancing Real-Time Avalanche Forecasting: Strengthening satellite-based avalanche monitoring systems for early warnings.
2. Improving Infrastructure Resilience: Constructing avalanche protection tunnels and snow-retention fences along highways.
3. Stronger Coordination Between Agencies: Integrating IMD, BRO, NDMA, and ITBP efforts for better disaster response.
4. Community Training & Awareness Programs: Educating local residents, trekkers, and military personnel on avalanche survival skills.
5. Encouraging Climate-Resilient Development: Limiting deforestation and unplanned construction in high-risk zones.

Conclusion:

Avalanches pose a significant threat in India’s Himalayan region, impacting human lives, infrastructure, and economic activities. Advanced forecasting, structural protection, and rescue preparedness are critical for minimizing avalanche disasters. Strengthening inter-agency collaboration and public awareness will further enhance India’s avalanche resilience.

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