RAPID: Death Valley after Hurricane Hilary: A study of desert landscape re-equilibration after extreme events

2023年8月20日，自20世纪30年代以来袭击加州的第一场热带风暴穿越死亡谷国家公园。一天之内，公园的降雨量达到2.2英寸，创下了相当于公园年平均降雨量的新纪录。这导致了前所未有的洪水和景观变化，其程度仍在确定中。在正常情况下，死亡谷是世界上最干旱的地方之一，景观变化由风和罕见的冲积和河流活动驱动。在飓风希拉里之后，大范围的山洪暴发和泥石流将从根本上改变景观，为了解极端事件后景观变化的速度和驱动因素提供了前所未有的机会。这项工作将确定风暴造成的米至百米尺度的变化，并定量记录风暴后的景观状态。泥石流、洪水和相关侵蚀的直接结果确定了未来景观开发和恢复的边界条件。这一基线景观状态正在积极衰减，必须迅速记录，以解决科学问题的景观变化后的极端事件，包括什么是景观再平衡的时间尺度在米到百米尺度？极端事件如何重新分配或创造新的沉积物源和沉积物汇？在极端事件发生后，植被如何恢复？这个奖项反映了NSF的法定使命，并被认为是值得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的支持。

On August 20, 2023, the first tropical storm to hit California since the 1930’s traversed Death Valley National Park. Total of 2.2 inches of rain fell over the park in a single day, setting a new record equivalent to the park’s average annual rainfall. This led to unprecedented flooding and landscape change, the extent of which is still being determined. During normal conditions, Death Valley is among the most arid places in the world with landscape change driven by wind and infrequent alluvial and fluvial activity. In the aftermath of Hurricane Hilary, widespread flash flooding and debris flows carved deep channels will fundamentally alter the landscape providing an unprecedented opportunity to learn about the rates and drivers of landscape change following extreme events.This work will identify meter- to hundred-meter-scale changes caused by the storm and quantitatively document the post-storm landscape state. The immediate results of debris flows, flooding, and associated erosion define the boundary condition for future landscape development and recovery. This baseline landscape state is actively decaying and must be rapidly documented to address scientific questions related to landscape change in the wake of extreme events including What are the timescales of landscape re-equilibration at meter- to hundred-meter scales? How do extreme events redistribute or create new sources and sinks of sediment? How does vegetation recover in the wake of an extreme event? Exploring these questions requires the proposed baseline dataset that will be collected in this effort.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.