The co-occurrence of freezing rain, ice accumulation and wind gusts (FZG) poses a significant hazard to infrastructure and transportation. However, quantification of the frequency and intensity of FZG is challenged by the lack of direct icing measurements. In this work, we evaluate and then apply an energy balance model to high-frequency data collected during 2005–2022 to derive hourly ice accumulation at 883 stations across the contiguous USA. These estimates are combined with wind gust observations to compute time series of hourly FZG hazard magnitude using the Sperry–Piltz Ice Accumulation (SPIA) index. Results are evaluated using Storm Reports of damage and economic disruption. The hourly SPIA estimates are also used to (i) derive a geospatial atlas of the hazard including the 50 yr return period event intensities for each US state derived using superstations, and (ii) describe storylines of significant events in terms of meteorological drivers and socioeconomic impacts. The highest values of SPIA during the 18 yr study period occur in a region extending from the Southern Great Plains over the Midwest into the densely populated Northeast. States in these regions also have high 50 yr return period maximum radial ice accumulation of 3–5 cm and co-occurring wind gusts >30 ms⁻¹. These values are comparable to past estimates for the 500 yr event which may imply this hazard has been previously underestimated. This atlas can be used to inform optimal FZG hazard mitigation strategies for each state/region.

中文翻译：

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量化美国大陆冻雨和阵风的复合危害

冻雨、积冰和阵风（FZG）同时发生，对基础设施和交通造成重大危害。然而，由于缺乏直接的结冰测量，FZG 的频率和强度的量化受到了挑战。在这项工作中，我们评估了能量平衡模型，然后将其应用于 2005 年至 2022 年期间收集的高频数据，以得出美国本土 883 个观测站每小时的冰积累量。这些估计与阵风观测相结合，使用 Sperry-Piltz 积冰 (SPIA) 指数计算每小时 FZG 灾害等级的时间序列。使用损害和经济破坏的风暴报告来评估结果。每小时 SPIA 估计还用于 (i) 得出灾害的地理空间图集，包括使用超级站得出的美国每个州 50 年重现期事件强度，以及 (ii) 从气象驱动因素和社会经济角度描述重大事件的故事情节影响。 18 年研究期间 SPIA 的最高值出现在从中西部南部大平原延伸到人口稠密的东北部的地区。这些地区各州的 50 年重现期最大径向积冰量也高达 3-5 厘米，并且同时发生>30 毫秒^{-1 的}阵风。这些值与过去对 500 年事件的估计相当，这可能意味着这种危险以前被低估了。该图集可用于为每个州/地区提供最佳 FZG 减灾策略。