Barrier Lake

About Barrier Lake

• A barrier lake is a temporary water body formed when landslide debris completely blocks a river or stream channel.
• Formation:
  • Triggering Event: A glacier collapse, landslide, rockfall or debris flow can dislodge rock, soil, mud and ice from steep mountain slopes.
  • Natural Dam Formation: The displaced material blocks a narrow river channel, causing water to accumulate upstream and form a temporary reservoir.
• Key Features:
  • Temporary Nature: Barrier lakes are temporary water bodies formed when natural debris blocks a river channel.
  • Unstable Barrier: The natural dam consists of loose soil, broken rock, mud, ice and other debris, making its stability uncertain.
  • Water Accumulation: Water accumulates behind the natural barrier, increasing pressure on it and potentially weakening it over time.
  • Landslide Lake Outburst Flood (LLOF): When the natural barrier suddenly fails, the stored water is released rapidly, causing a potentially devastating flood downstream.
  • Variable Lifespan: A barrier dam may fail within days or even decades after its formation.

• 2026: A barrier lake formed near the Chhochen Khola–Purepu Tsangpo rivers along the Nepal-Tibet border.
• 2014: A landslide lake formed across the Sunkoshi River in Nepal after a huge landslide.
• 2008: Landslide dams formed along rivers near the Qinghai-Tibet Plateau after the Wenchuan earthquake.
• 2000: The Yigong landslide created a 60-metre-high dam on the Yigong Tsangpo River.
• 1835–1966: A rock-and-debris dam formed over the Tagermarch River in Kyrgyzstan and failed after 131 years.