  Floods affected more than 2 billion people worldwide from 1998 to 2017 and
their occurrence is expected to increase due to climate warming, population
growth and rapid urbanization. Recent approaches for understanding the
resilience of transportation networks when facing floods mostly use the
framework of percolation but we show here on a realistic high-resolution flood
simulation that it is inadequate. Indeed, the giant connected component is not
relevant and instead, we propose to partition the road network in terms of
accessibility of local towns and define new measures that characterize the
impact of the flooding event. Our analysis allows to identify cities that will
be pivotal during the flooding by providing to a large number of individuals
critical services such as hospitalization services, food supply, etc. This
approach is particularly relevant for practical risk management and will help
decision makers for allocating resources in space and time.
