<p>Global warming is increasing both the frequency, severity, and complexity of glacier-related hazards in high-altitude regions. However, understanding the underlying triggers and multifaceted nature of these hazards requires further investigation. On 28 May 2025, a catastrophic ice-rock avalanche occurred in the Lötschental, Swiss Alps, destroying Blatten village and causing one fatality despite prior evacuation. Three-dimensional topographic modeling indicates that ~ 8.86 Mm³ of rock and ice collapsed from the Kleines Nesthorn and the lower Birch Glacier, transforming into a highly mobile debris avalanche with a 1828-m vertical drop and 3745-m travel distance, burying much of the village and damming the Lonza River. Associated intense air blasts and extensive debris deposition caused ecological damage, uprooting and reshaping the floodplain. Comprehensive analysis of field observations, UAV photogrammetry, remote-sensing interpretation, meteorological records, and seismic signals reveals that the event was driven by progressive destabilization under complex, multi-factor interactions. Jointed rock masses and topography made the slope susceptible to failure, while early precipitation and freeze-thaw cycles accelerated rock deformation and glacier flow, ultimately triggering a large-scale collapse driven by thermally and pressure-induced meltwater. We further discuss how climate warming drives domino-style, multi-stage ice-rock avalanche hazard chains. Water-rich moraines, frictional meltwater, and local topography collectively enhance the mobility and destructive potential of the debris avalanche, amplifying threats to downstream mountain communities and ecosystems. Our findings highlight the importance of proactive measures, including real-time glacier monitoring, early warning systems, and hazard mitigation infrastructure, alongside sustained efforts to address climate change.</p>