Can a Catastrophic Ice–Rock Avalanche Generate Its Own Early-Warning Signal? A Testable Seismic–Debris-Flow Hypothesis from the 26 August 2026 Nepal–Tibet Disaster

This technical note presents a testable source-generated early-warning hypothesis motivated by the catastrophic ice–rock avalanche and cascading debris-flow/flood event that affected the Nepal–Tibet border region on 26 August 2026. Preliminary official assessments indicate that the high-altitude glacial collapse generated a strong seismic signal and subsequently transformed into a highly mobile debris flow through fragmentation, moraine and channel-material entrainment, and incorporation of water and ice. This observation motivates the central hypothesis that a sufficiently large ice–rock avalanche may generate a characteristic seismic signal that can be detected and classified before the resulting destructive debris-flow or flood surge reaches downstream communities. The proposed framework integrates seismic detection and classification, terrain-constrained runout modelling, probabilistic arrival-time estimation, and downstream warning. A complementary monitoring mode is proposed for secondary hazards associated with channel blockage, barrier-lake formation, overflow, or breach. The note explicitly distinguishes documented observations, calculated first-order estimates, testable hypotheses, and unresolved event parameters. It does not claim a definitive reconstruction of the 26 August 2026 event or a validated operational warning system. Instead, it defines falsifiable predictions and a retrospective validation framework using primary seismic waveforms, pre- and post-event satellite observations, digital elevation models, synchronized video records, and hydrological measurements. Central hypothesis: A catastrophic mass movement may not only generate the hazard; it may also generate the first remotely detectable signal of that hazard. Evidence and numerical estimates are based on publicly available information through 28 August 2026 and should be updated as primary datasets and formal post-event investigations become available. Keywords: ice–rock avalanche; glacier collapse; debris flow; seismic detection; early warning; cascading hazards; runout modelling; Nepal; Tibet; Himalaya. DOI: 10.5281/zenodo.22140113