A rapid warning value chain assessment for Storm Ciarán

This case study event utilizes a rapid warning value chain assessment template (https://doi.org/10.5281/zenodo.10457434) produced by the World Meteorological Organisation's High Impact Weather (HIWeather) project, to evaluate the performance of early warnings for multiple hazards associated with Storm Ciarán. This storm affected southern parts of the UK, the Channel Islands, and northern France on 2 November 2023. By applying this comprehensive tool, the Met Office, Flood Forecasting Centre, and British Geological Survey conducted an end-to-end assessment of the warning process, from initial forecast to response from the public and energency responders. The analysis highlights key strengths and areas for improvement in the communication and effectiveness of the warning systems, taking account of the multiple hazards that were forecast. Results provide valuable insights and best practices for enhancing future multi-hazard warnings.