Roads in mountains areas are exposed to natural hazards such as snow avalanches, torrent floods and rockfalls. Risk depends both on hazard, direct and indirect vulnerability. In case of roads, the indirect vulnerability relates to the consequences of road closures which is rarely assessed. The criticality of these closures depends on the importance of road sections. A new methodology is proposed in the context of natural risks management in mountains. Based on structural networks analysis, it aims to assess the accessibility level of mountain territories and to identify critical roads sections depending both on their exposure to phenomenons but also on the importance of roads on economic, social, environmental contexts. The structural network analysis allows to describe how far the network properties conditions the accessibility from one point to another. This approach is combined to multicriteria decision making to assess importance according to economic, social or human factors but also fragility, resilience or risk sensitivity on road sections.