Rethinking cascading high-mountain hazards and early warning in the Himalayas

Abstract Glacial lake outburst floods (GLOFs) remain a major Himalayan hazard, but recent disasters show that destructive floods develop through several cascading pathways. Seven recent events across Nepal and the wider Himalaya show how lake outburst, avalanche, slope failure and supraglacial drainage can be amplified by sediment entrainment and debris-flow transformation, leading to similar downstream consequences. To reduce risk from such cascading hazards, we argue for a four-tier cascade-aware approach spanning from source-zone monitoring, failure detection, early warning to preparedness, planning and governance.