In weather risk communication, there is a disconnect between numerical models and community members’ experiences. To help resolve this issue, the authors propose a topological method to identify community risk thresholds, arguing that they offer a middle ground that enables more robust communication about risk. The authors surveyed 1,429 participants, including decision-makers and public audience members, who responded to probabilistic visualizations from five National Weather Service offices. The results reveal that audiences engage in sophisticated risk assessment by drawing on multiple dimensions that can be communicated as community risk thresholds. Embedding these thresholds in the forecast can better link numerical and experiential risk.

We conducted a two-phase study with five National Weather Service (NWS) forecast offices in the Western United States region to improve the visualization of probabilistic forecast information (PFI) for their communities. We advance the concept of community risk thresholds (CRT), based on rhetorical commonplaces (communal beliefs, norms, and values) as a productive focus for forecasting. Our results suggest that CRTs are a promising heuristic for simplifying the visual presentation of PFI and increasing its community utility. We discuss the synergies and challenges of action research projects in weather risk communication and conclude by projecting future work focused on (a) visualizing community risk thresholds and (b) identifying productive pairings between weather hazard type and graphic genre.