Developing a hazard‐impact model to support impact‐based forecasts and warnings: The Vehicle OverTurning (VOT) Model

Abstract

Abstract Impact‐based weather warnings have been issued by the Met Office since 2011. The National Severe Weather Warning Service (NSWWS) uses a risk matrix combining the level of impacts the weather may cause and the likelihood of those impacts occurring to define a warning level. The impact assessment can be considered subjective being predominantly based on meteorologist expertise and experience of past high‐impact weather events and discussions with local advisors. The Vehicle OverTurning (VOT) model is a prototype Hazard Impact Model developed to test the hypothesis that risk models can be run in real time for short‐term weather‐related hazards. The method intends to provide an objective, consistent assessment of potential risk to road users in Great Britain during high‐wind events. It aims to support the production of NSWWS wind warnings by highlighting areas of the road network that are at risk of disruption due to vehicles overturning. The VOT model does this by combining probabilistic hazard information with vulnerability and exposure data to produce a risk of vehicle overturning forecast. The model is being demonstrated with operational meteorologists at the Met Office. Initial reviews of the model's output indicate that the scientific approach used in this prototype can identify routes with a higher risk of vehicle overturning, associated with strong wind events. Ad hoc feedback from forecasters support the authors’ belief that the risk modelling approach is useful to operational meteorologists when issuing weather warnings.

Keywords

• ensemble forecasts
• exposure
• hazard
• impact‐based forecasting
• risk
• severe weather warnings