RAPID: Land surface hazards under accelerating climate change: Example from 2023 Hurricane Hilary

气候对固体地球灾害的影响，如山体滑坡、泥石流、河流聚集和洪水，在历史上很少受到关注，但近年来，这种影响正在破坏社区并改变我们生活的环境。我们迫切需要了解新的气候机制是如何产生风暴的，这些风暴引发了前所未有的侵蚀、地面破坏和沉积。例如，干旱环境是由长期缓慢的地貌活动形成的，其间穿插着可以在地质瞬间改变景观的重大事件。这些灾害通常由大风暴引发，同时也会带来一系列危害，包括洪水、山体滑坡和泥石流，这些灾害可能会破坏主要基础设施（如道路、建筑物）以及自然和文化遗产。2023年8月，四级太平洋飓风希拉里在南加州引发了前所未有的热带风暴警报，从墨西哥-美国边境一直延伸到洛杉矶县的北部和东部地区。与大多数冬季降水以狭窄、集中的方式到达该地区不同，希拉里飓风将强降雨分布在南加州的大片地区，这为研究一次重大降水事件对广泛地貌和社会的影响提供了机会。受影响最严重的地区是通常干旱的沙漠地区，那里的降雨量超过了典型的年降雨量，并引发了泥石流、突发洪水和泥沙碎屑波。该奖项的主要目标是收集易腐烂的现场数据，以深入了解泥石流观测，从而对灾害级联进行长期预测。这种可以检验模型和推动对陆地表面灾害的新认识的直接观测很少，部分原因是主要的景观变化事件虽然可能是灾难性的，但很少发生，因此很少有利用现代技术记录的自然例子。光探测和测距（激光雷达或激光扫描）和运动结构（SfM）等技术使变化检测和量化能够提供以前难以捉摸的见解。这些数据包括陆地表面变化的详细记录，被侵蚀和再沉积的地面物质的性质，以及对基础设施的影响。这项研究将在陆地表面灾害中心（CLaSH）的结构内进行，从而支持社区建设倡议，并通过包括新的研究人员和以前没有参与过CLaSH的学生，让跨学科的研究人员参与与灾害相关的科学。这项研究产生的数据将通过开放访问存储库公开提供，使更广泛的研究团体能够利用经验来了解飓风希拉里对地质环境的影响，同时也指导下一代危害级联模型，该模型可以根据从该项目收集的现场数据进行验证。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The climate impact on solid earth hazards, such as landslides, debris flows, river aggregation and flooding, has historically received little attention, but in recent years, this impact is disrupting communities and altering the environment we live in. There is an urgent need to understand how new climate regimes are generating storms that unleash unprecedented episodes of erosion, ground failure and deposition. For example, arid environments are shaped by long periods of slow geomorphic activity, punctuated by major events that can transform landscapes in a geological instant. These events, often triggered by major storms, also present a range of hazards, including floods, landslides, and debris flows that can damage major infrastructure (e.g., roads, buildings) as well as natural and cultural heritage sites. The August 2023 Hurricane Hilary was a Category 4 Pacific hurricane that triggered an unprecedented tropical-storm-warning for Southern California, extending from the Mexico-US border to regions north and east of Los Angeles County. Unlike most of the wintertime precipitation that arrives in this region in narrow, concentrated bands, Hurricane Hilary distributed heavy rainfall across a wide swath of southern California, providing an opportunity to study the widespread geomorphic and societal impact of a major precipitation event. The most severely affected regions have been the normally arid desert regions, which suffered heavy rainfall in excess of typical annual totals with triggered debris flows, flash flooding and sediment debris waves. Collection of perishable field data is the main goal of this award, to gain insights into the debris flow observations that enable longer term predictions of the hazard cascade. Such direct observations that can test models and drive new understanding of land surface hazards are sparse in part because major landscape-changing events, although potentially catastrophic, are rare and thus few natural examples are well documented using modern technologies. Technologies like Light Detection and Ranging (LiDAR, or laser scanning) and Structure-from-Motion (SfM) enable change detection and quantification that provide previously elusive insights. Such data include detailed records of land surface change, the properties of ground materials that were eroded and redeposited, and impact on infrastructure. The research will be conducted within the structure of the Center for Land Surface Hazards (CLaSH), thereby supporting community building initiative and engaging researchers across disciplines in hazard-related science, by including new researchers, and students who were not previously involved in CLaSH. Data generated from this research will be made publicly available via open access repositories, enabling use by the wider research community to empirically understand the impact of Hurricane Hilary on the geologic environment, but also guide next-generation hazard cascade models that can be validated against the field data collected from this project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.