Disasters triggered by extreme precipitation events i.e., landslides,
debris flows, and floods cause devastating damages to lives,
infrastructure, and the economy. Under a warming climate, precipitation
extremes and the occurrence of debris flows are further expected to
intensify. Driven by extreme runoff, the triggering of debris flows can
be simultaneous. Their concurrent occurrence multiplies complexity in
decision-making during emergencies. Despite advancements in geotechnics
and network science, a systematic framework to analyze the impact of
debris flows on road networks is lacking. While network science-based
approaches work on large-scale, geotechnics-based damage assessments are
done solely on a site-to-site basis. Here we develop an integrated
approach to analyze the impacts of simultaneous debris flows on road
networks. The approach includes a novel infinite slope-based
one-dimensional numerical model that simulates runoff-induced erosion
and a network science-based mathematical model for road failures. This
study covers multiple catastrophic events of debris flows that occurred
in different geological and climate settings i.e., post-earthquake,
post-volcanic, and post-wildfire environments. We perform
spatio-temporal simulations of initiation and runout of debris flows and
calculate the damage caused on individual road segments. We validate the
model results using metadata. Our results show even remote local
disturbances caused by successive debris flows upstream may lead to
complete cascading disruption of the network downstream. Our unified
strategy opens avenues to understand the resilience of critical
infrastructure networks against catastrophic debris flows.