Cascading disasters: How the 2023 Türkiye-Syria earthquake was amplified by an atmospheric river

Strong earthquakes in mountain landscapes can trigger widespread slope failures, initiating chains of multiple hydro-geomorphic hazards such as channel blockage, instability, flooding, and coarse sedimentation. These impacts disrupting ongoing response operations may be fueled and potentially amplified by extreme post-seismic precipitation delivered by atmospheric rivers (ARs), which can form continent-spanning corridors of concentrated moisture. Yet, such cases of ARs occurring in the aftermath of major earthquakes have remained unreported to the best of our knowledge. Here, we document the combined effects of seismic and precipitation extremes that perturbed the area struck by the February 6, 2023 Türkiye-Syrian earthquakes (Mw 7.8 and 7.6), the largest seismic sequence ever recorded in the region. Strong ground shaking triggered thousands of landslides and was followed, 36 days later, by an exceptionally strong AR bringing severe precipitation with up to 183 mm in 20 hour. This rainfall induced yet more landslides, debris flows, and flooding, disrupting recovery efforts, affecting earthquake victims and temporary settlement areas, and claiming more lives. This unprecedented disaster highlights the need to revise rapid hazard assessment protocols to account better for hazard cascades arising from tightly timed seismic and weather extremes.