Risks associated with natural hazards such as hurricanes are increasingly communicated on social media. For hurricane risk communication, visual information products—graphics—generated by meteorologists and scientists at weather agencies portray forecasts and atmospheric conditions and are offered to parsimoniously convey predictions of severe storms. This research considers risk interactivity by examining a particular hurricane graphic which has shown in previous research to have a distinctive diffusion signature: the ‘spaghetti plot’, which contains multiple discrete lines depicting a storm’s possible path. We first analyzed a large dataset of microblog interactions around spaghetti plots between members of the public and authoritative weather sources within the US during the 2017 Atlantic hurricane season. We then conducted interviews with a sample of the weather authorities after preliminary findings sketched the role that experts have in such communications. Findings describe how people make sense of risk dialogically over graphics, and show the presence of a fundamental tension in risk communication between accuracy and ambiguity. The interactive effort combats the unintended declarative quality of the graphical risk representation through communicative acts that maintain a hazard’s inherent ambiguity until risk can be foreclosed. We consider theoretical and practice-based implications of the limits and potentials of graphical risk representations and of widely diffused scientific communication, and offer reasons we need CSCW attention paid to the larger enterprise of risk communication.

与自然灾害（例如飓风）相关的风险越来越多地在社交媒体上传达。对于飓风风险沟通，气象机构的气象学家和科学家生成的视觉信息产品（图形）描述了天气预报和大气状况，并提供了这些信息来简化对大风暴的预测。这项研究通过检查特定的飓风图来考虑风险交互作用，该飓风图在先前的研究中显示出独特的扩散特征：“意大利面条图”，其中包含描述风暴的可能路径的多条离散线。我们首先分析了2017年大西洋飓风季节美国公众和权威天气源之间的意大利面条区周围的微博客互动的大型数据集。在初步发现勾勒出专家在此类交流中的作用后，我们随后与气象部门的样本进行了访谈。研究结果描述了人们如何通过图形对话来理解风险，并表明了风险之间存在根本性的张力沟通准确性和模糊性。交互工作通过保持危险固有的模糊性的沟通行为，消除了风险表示形式的意料之外的声明性质量，直到可以消除风险为止。我们考虑图形风险表示和广泛传播的科学交流的局限性和潜力的基于理论和实践的含义，并提供我们需要CSCW注意更大的风险交流企业的原因。