  The measurement and mapping of transportation network vulnerability to
natural hazards constitute subjects of global interest, especially due to
climate change, and for a sustainable development agenda. During a flood, some
elements of a transportation network can be affected, causing loss of life of
people and damage to vehicles, streets/roads, and other logistics services,
sometimes with severe economic impacts. The Network Science approach may offer
a valuable perspective considering one type of vulnerability related to network
type critical infrastructures: the topological vulnerability. The topological
vulnerability index associated with an element is defined as the reduction in
the network's average efficiency due to the removal of the set of edges related
to that element. We present a topological vulnerability index analysis for the
highways in the state of Santa Catarina, Brazil, and produce a map considering
that index and the areas susceptible to urban floods and landslides. The risk
knowledge, combining hazard and vulnerability, is the first pillar of an Early
Warning System, and represent an important tool for stakeholders from the
transportation sector in a disaster risk reduction agenda.
