Echoes of Past, Warning for Future, Pg12

Key Highlights:

• Devastating flooding in Nepal’s Bhotekoshi-Trishuli river has claimed over 350 lives, highlighting the Himalayan region's vulnerability to disasters.
• The event, originating in Nepal's Rasua district, was initially reported as a 4.4 magnitude earthquake by the US Geological Survey, later revised to a 5.2 magnitude glacial collapse and debris flow.
• Experts suggest the disaster could be a Glacial Lake Outburst Flood (GLOF) or a breach in a supra-glacial lake.
• The incident draws parallels with past Indian disasters such as the Kedarnath tragedy (2013), Chamoli disaster (2021), and the South Lhonak lake (2023) event in Sikkim.
• India's National Disaster Management Authority (NDMA) has launched the National GLOF Risk Mitigation Programme (NGRMP) to install early warning systems in 19 high-risk glacial lakes across the Indian Himalayas.

Detailed Insights:

• The Nepal flooding involved a sudden release of water, stones, and soil, leading to cascading events like erosion, landslides, and widespread destruction downstream.
• The US Geological Survey initially misidentified the event as an earthquake, later clarifying it as a large glacial collapse and debris flow based on further analysis.
• Glacial Lake Outburst Floods (GLOFs), as seen in the Kedarnath tragedy (2013), involve breaches in glacial lakes, while ice and rock avalanches caused the Chamoli disaster (2021).
• Supra-glacial lakes are lakes formed on the surface of glaciers, whose breaches can cause significant floods without visible ice blocks.
• The Himalayan region is inherently fragile due to climate change, increasing population pressure, and frequent seismic activity, making it prone to multi-hazard disasters.
• The Sikkim (2023) event, involving the South Lhonak lake, demonstrated how a glacier collapse can trigger massive flash floods and sediment flow.
• Mitigation strategies for such events include installing early warning systems, preparing comprehensive evacuation plans, and strictly regulating construction in ecologically sensitive areas.
• The International Centre for Integrated Mountain Development (ICIMOD) is a key research organization working on the Himalayas, contributing to understanding these complex phenomena.

Key Concepts Involved:

• Glacial Lake Outburst Flood (GLOF): A sudden release of a significant volume of water from a glacial lake due to the failure of its natural dam.
• Supra-glacial lakes: Lakes that form on the surface of glaciers, often due to accelerated melting, and can breach causing flash floods.
• Cascading disaster: An event where an initial hazard triggers a series of subsequent, interconnected hazards, amplifying the overall impact.
• Early Warning Systems: Technologies and procedures designed to detect impending hazards and disseminate timely alerts to affected populations.
• National GLOF Risk Mitigation Programme (NGRMP): An initiative by the NDMA to install early warning systems at high-risk glacial lakes in the Indian Himalayas.