The effect of likelihood and impact information on public response to severe weather warnings

This study investigates how communicating probabilistic information influences public responses to impact-based weather warnings. Focusing on the UK Met Office’s National Severe Weather Warning Service, which issues colour-coded warnings based on the likelihood and severity of impacts, the research examines whether explicitly presenting probability and impact information affects perceptions and behavioural intentions. Using a mixed-factorial online experiment, 550 UK residents from two regions were randomly assigned to one of three warning formats—colour-only, text, or risk matrix—and presented with warnings representing different combinations of likelihood and impact severity. 

The findings show that when probability and impact information is provided, high-likelihood, high-impact red warnings generate the strongest perceptions of risk, concern, trust, and intention to take protective action, followed by amber warnings with high probability and moderate impact. In contrast, amber warnings describing low-probability but high-impact events elicit lower perceived risk, trust, and behavioural intention. Overall, the results indicate that people are sensitive to probabilistic information, and that communicating low likelihood can unintentionally reduce concern and response, even when potential impacts are severe, raising important considerations for impact-based weather warning communication.