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. 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 rare 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. This event gave the Clash team an opportunity to pivot the scenario planning exercise onto a real event. During the final day of the Jackson Community Meeting (and while the storm was starting to impact southern California in real time!) the group engaged in a pre-event planning session focused on rapid deployments and collection of perishable data that addresses the hazard cascade. Over the following week, the PI team developed and were subsequently awarded  a NSF-RAPID proposal. The field work took place in November and was concentrated in the Death Valley area and burn areas of the San Gabriel/ San Bernardino Mountains. Broader impacts include improved land surface hazards models, understanding of the impact of precipitation-triggered debris flows on infrastructure, and training of students in field data planning and acquisition following disasters. Graduate students from multiple institutions and at varying career stages led the field component including data collection, providing in-practice opportunities for mentoring and cohort building. The research will be conducted by the Center for Land Surface Hazards (CLaSH) team, thereby supporting a community building initiative and engaging researchers across disciplines in hazard-related science, by including new researchers 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. 

The Clash PI and steering committee team will host several events at the AGU Fall Meeting in San Francisco, including an oral and poster session on cascading hazards and our second Town Hall. We plan to give an overview of the Center vision and solicit feedback from attendees through active polling, Q&A periods and discussion. Come join us!

Links to the AGU sessions: (default is to show your local time not PST) (Town Hall) (oral session) (poster session)

Clash hosted a two-day in-person workshop on Oct 9-10 in Boulder, CO in partnership with CSDMS that focused on identifying future research and integration activities needed to couple process models for advancing hazard cascade predictive capability. We attracted a wide array of disciplinary scientists that brought a suite of new and exciting perspectives on modeling hazard cascades. During the meeting we developed approaches to generalized hazard cascade systems and identified linkages between model (process) components that are ripe for implementation and study. The product of the two-part modeling series will be contributed to our Research Gap white paper and will inform our NSF Geohazards Center proposal in March 2024. 

On July 17 – 22, Clash and partner Earthscope hosted a pilot graduate summer school, led by postdoc Stratis Karantanellis and steering committee member, Sean Gallen. The program offered an immersive learning experience using a mock hazard response team effort that resembled real-world study of coordinated hazard event data by interdisciplinary teams. The pilot’s collaborative, interdisciplinary focus around the breadth of land-surface hazards and their cascade is a distinguishing theme separate from more discipline-specific programs in geomorphic hazards (such as the LARAM and iRALL Summer Schools that focus specifically on landslides). Participants were exposed to various field technologies to measure land surface change in the Rocky Mountains, CO, affected by the 2020 Cameron Peak fire. Students gained practical knowledge in team project planning, data acquisition, processing, and analysis using cutting-edge geodetic techniques, including Uncrewed Aerial Vehicles (UAVs) and Photogrammetry, Terrestrial Laser Scanning (TLS), and differential GNSS with RTK corrections. Theoretical and practical skills advanced graduate students’ engagement with technology for their ongoing research efforts, while also fostering cohort building of interdisciplinary scientists from a range of institutions and cultural backgrounds. The program emphasized inclusive teaching practices around technical training, supported by education experts and technicians from the NSF-supported EarthScope Consortium. 162 applications were received for 20 spots in this course in just 4 days of advertisement, which demonstrates the broad interest of graduate students for such training.

Teaching team: Stratis Karantanellis, Sean Gallen, Ben Mason, Adrianna Trusiak, Erika Schreiber, Sam Beane, Beth Pratt-Situla, Marin Clark