Urban infrastructures are essential to the health, safety, security and economic well-being of citizens and organisations. Therefore, the managers of critical infrastructures (CI) and infrastructure systems in urban areas need to be constantly aware of and prepared for to any man-made and natural disasters. In this paper, we propose a structured approach to assess extreme weather impacts on CI and discuss how resilience and risk tolerance of critical infrastructure can be enhanced. The approach is aimed at supporting CI owners' and managers' decision-making on a strategic level. It follows a process flow from hazard and CI identification, vulnerability analysis, potential damage estimation, loss assessment to identification and assessment of measures. The approach incorporates many elements, phases and methods from hazard assessment, vulnerability assessment, risk assessment and cost-benefit analysis (CBA), and combines and incorporates them into one aggregated structure, thus providing a holistic view to risk management and CI protection. The proposed approach is flexible in the sense that it encompasses not only a rigorous quantitative assessment, but also allows for a semi-quantitative or qualitative assessment. In addition, the approach enhances transparency of decision making and contributes to more comprehensive use of available information. The paper is based on research carried out in the INTACT and HARMONISE projects, which are co-funded by the European Union under the 7th Framework Programme.