A major concern for transmission system operators is effectively managing electrical systems during extreme weather events. This requires new methods and tools to support exercise planning by predicting critical conditions on the network and to quantify the benefits of measures implemented to improve system performance in these events. For this reason, the concept of resilience is particularly useful for building an adequate evaluation framework. This article presents an in-depth resilience assessment methodology to support the assessment of the system response to wet snowfall under different assumptions of threat intensity and component vulnerability, including the modeling of countermeasures (anti-torsion devices and icephobic coatings) aimed at improving the resilience of the system. In particular, anti-torsion devices and icephobic coatings are two measures aimed at strengthening the network to deal with wet snow events. Case studies applied to a model of a realistic EHV/HV transmission system demonstrate the potential of the tool, which can be useful for a future quantitative techno-economic evaluation of the portfolio of measures for improving resilience.