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. 

We invite submissions to our session on hazards across Earth’s surface. We are particularly interested to hear from a range of processes that lead to hazards and their interactions across diverse environments! The session will explore the cutting-edge science at the heart of the NSF-sponsored Center for Land Surface Hazards (CLaSH) catalyst proposal and recent NSF initiative to support fundamental research that informs adaptive and/or resilient responses to natural hazards and disasters (

Invited speakers:

Chris Massey, GNS, New Zealand

Katy Barnhart, USGS, USA


Session Title:

EP006. Cascading Hazards: Linking Processes Across Earth’s Surface

Session Description:

Natural hazards often initiate a cascade of processes across the Earth’s surface that can propagate the consequences to life and property well beyond the triggering event. Both climatic (e.g., weather events, wildfire, and climate change) and geologic (e.g., earthquake and volcano) events can trigger landslides, debris flow, as well as multi-hazard chains related to sedimentation and floods. Moreover, the spatially variable and ever evolving properties of the Earth’s surface may induce a range of compound and cascading hazards as the landscape responds to these changing conditions. This session will highlight the cutting-edge science at the core of a proposed NSF-sponsored Solid Earth Geohazards Center for Land Surface Hazards (CLaSH). Presentations will explore both individual processes and the hazard cascade across a range of environments of Earth’s surface. We encourage submissions from various aspects of cascading hazard chains and approaches such as observational, theoretical, modeling, and applied studies.


The conveners:

Brian Yanites, Indiana University-Bloomington

Corina Cerovski-Darriau, USGS

Ben Mason, USGS

Seulgi Moon, UCLA

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

On August 17 – 20, 2023, Clash hosted a “Community Meeting” in Jackson, WY at the University of Michigan Camp Davis field station. Thirty members of the Clash team, partners, stakeholders and experts in the scientific community gathered to discuss progress with the Catalyst project, assess Center research and education goals, and contribute broadly to the Center Strategic Plan. The meeting was followed by an intense 1 ½ day planning session with the steering committee and PI team to draft the science plan of the Center.

Led by Steering Committee member Brian Yanites, we have initiated a research-based gap analysis and evaluation of data relevant to Center research themes, which we view as foundational to preparation of a Center strategic plan and necessary for exploring the connection between basic and applied science. A full draft of this white paper was shared at the 2023 Jackson Community Meeting where broad input was solicited. Scientific community engagement was advanced through focus groups that were developed at Community Meeting and engaged in regular meetings for two months. Focus groups contributed disciplinary specific knowledge to the paper effort from a broad cross-section of scientific disciplines. A complete document is planned for the end of the year.

  • Are you interested in studying land surface hazards like landslides and post-fire debris flow? And understanding how these processes relate to triggers like earthquakes and storms?
  • Does the study of extreme events to serve societal needs and advance understanding of how geomorphic systems work appeal to you?
  • Would training on cutting-edge technology to measure land surface change following disasters advance your graduate education?

If these questions speak to you, check out our graduate summer short-course sponsored by the Center for Land Surface Hazards (CLaSH). It’s a fully-funded opportunity by NSF to advance your skills, knowledge and connections to other researchers with a intensive, hands-on training experience in Colorado this summer. Better yet, it is an action-packed, six-day experience designed to fit into busy graduate student schedules. Your advisor is sure to say YES!

Eligibility: The course is open to any graduate student (MS or PhD) in relevant geoscience and engineering fields who is currently enrolled or matriculating in Fall 2023.

Course Description: This class will provide hands-on training for geodetic field surveys to generate high-resolution digital surface models and practical laboratory experience with data processing and digital surface model change detection. The study sites are mountain regions affected by the 2020 Cameron Peak fire that have experienced significant geomorphic change via post-wildfire erosion and flooding. Participants will gain hands-on experience with Uncrewed Arial Vehicles (UAVs) and Photogrammetry, Terrestrial Laser Scanning (TLS), and kinematic GPS and learn how to design and implement field surveys for surface change detection (supported by EarthScope Consortium). After the data acquisition is complete, participants will work with newly generated and existing datasets of the study sites to conduct change detection exercises in the computer lab on CSU’s Mountain Campus.

Location: Colorado State University, Mountain Campus (~2 hr drive from Fort Collins, CO).

Dates: Arrive in Fort Collins, CO, in the early afternoon of Monday, July 17th, and buses will take participants to CSU’s Mountain Campus. Depart CSU’s Mountain Campus on the morning of Saturday, July 22nd.

Instructors: Erika Schreiber (EarthScope Consortium), Samuel Beane (EarthScope Consortium), Ben Mason (USGS), Sean F. Gallen (CSU)

Accommodations: Shared cabins with bunks (Conference Center Cabins). Each cabin has six rooms. Each room has three to four bunks and its own bathroom. The facility has a cafeteria where participants and instructors will eat breakfast and dinner. Most days, participants will be provided with a bagged lunch.

Planned Activities Outline:

  • July 17th – Arrive in Fort Collins, CO, in the early afternoon. Load onto busses and arrive at Mountain Campus to get settled before dinner and a safety and overview briefing of the upcoming schedule.
  • July 18th – Meet on campus for a summary of previous and ongoing work related to the post-fire hazard cascade. This will be followed by a lecture on the basics of the equipment used during the course and considerations of designing a survey. Depart Mountain Campus to visit the fire burn site. Break into groups and begin surveys. Return to the Mountain Campus before dinner.
  • July 19th – Depart Mountain Campus to visit the fire burn site. Break into groups and continue surveys. Return to the Mountain Campus before dinner.
  • July 20th – If needed, finalize field surveys and return to Mountain Campus after lunch for a lecture on data processing and digital surface model change detection.
  • July 21st – Work in groups on change detection assignments provided newly generated and pre-existing data from the survey area.
  • July 22nd – Depart Mountain Campus after breakfast for Fort Collins, CO.



May 8: Applicants are notified of review committee decisions

May 15: Selected applicants must confirm acceptance and commitment to attend

Questions can be sent to More information about the CLaSH Catalyst at

Apply to CLaSH Graduate Summer Field Course

As the geoscience community confronts the challenges of interpreting and predicting the behavior of hazard cascades on a rapidly changing planet, we seek community input and vision on the formulation and coupling of models that address critical land surface processes. By convening a Modeling Expo in a two-part series, we will galvanize intellectual curiosity and creative thinking on hazard cascades. Most importantly, we invite you to attend and bring your modeling expertise!

Part 1: On May 1 and 2, the CLaSH team hosted a virtual Modeling Expo that featured 8 sessions with each focusing on individual process components of hazard cascades, such as flooding, landslides, earthquakes, and storms. The goals were to promote the awareness and study of hazard cascades, learn about state-of-the-art approaches to process modeling, and identify geoscientists with expertise and interest in our fall 2023 in-person workshop focused on model coupling and integration for risk assessment. The 2-day virtual event was advertised on numerous listservs and over 40 speakers from a wide array of career stages and backgrounds volunteered to present their work. In addition, the session coordinators recruited geoscientists with demonstrated expertise in surface process hazard modeling and the vast majority of those invited were eager to contribute. The speakers were asked to describe their models and implementation from a conceptual standpoint as well as imagine their contribution to coupled hazard cascade simulations. The sessions were composed of several 7-minute talks as well as ample time for discussion and synthesis at the conclusion of each session. CLaSH administrative staff were essential to the planning and execution of the event which enabled the CLaSH team to focus on science content. 

The average attendance over the course of the Expo averaged over 100 and the sessions were recorded in order to encourage additional viewership. During each session, the CLaSH team facilitated questions that were generated by attendees via zoom chat and a google document and the result was a vibrant discussion with the speakers and other attendees. Notably, the Exposure and Risk session featured talks by federal agency social scientists and insurance experts among others and these highlighted the importance of translating surface process hazard modeling into accessible and legible products that can inform regulatory, commercial, and other societal decision-making. In addition, many of the sessions included talks featuring highly innovative modeling frameworks that reflect significant community investment in land surface cascade hazards. 

The CLaSH team is currently planning the in-person Modeling Expo for Fall 2023.

The schedule for the May 1-2, 2023, virtual Modeling Expo is as follows:

Monday, May 1, 2023 (All times Pacific)

  • 8:00-9:00 am: Critical zone and near-surface properties (Seulgi Moon)
    • Seulgi Moon (UCLA) “Prediction of bedrock weathering based on the topographic stress model”
    • Harihar Rajaram (Johns Hopkins), “Advancing Coupled Process Models for Critical Zone Evolution”
    • Mong-Han Huang (U of Maryland) Using near-surface geophysics to constrain moisture and porosity distribution in the critical zones”
    • Miles Reed (U Wisconsin) “Modeling cosmogenic nuclides in transiently evolving topography and chemically weathering soils”
    • Roman Dibiase (Penn State) “Post-fire sediment delivery in steep landscapes

  • 9:00-10:00 am: Geologic forcing (Ben Mason)
    • Kate Allstadt (USGS), “Near-real-time Modeling of Earthquake-triggered Ground Failure”
    • Alex Hatem (USGS), “Fault geometries and activity rates for use in the 2023 update of the U.S. National Seismic Hazard Model
    • Robb Moss (USGS), “Probabilistic Forecasting of Surface Fault Rupture”
    • Erin McEwan (Canterbury), “Coseismic river flooding and avulsion: A new approach for modelling earthquake-induced flood hazards”
    • Theron Finley (Victoria), TBA

  • 10:00-11:00 am: Climate/environmental forcing (Jane Baldwin)
    • Jane Baldwin (UC Irvine), “Climate modeling overview”
    • Amir Aghakouchak (UC Irvine), “Modeling Cascading Hazards”
    • Park Williams (UCLA), “Modeling Forest Fire in the Western United States”
    • Chuxuan Li (Northwestern)  “Augmentation of WRF-Hydro to simulate postfire debris flow susceptibility at regional scales
    • Deanna Nash (UC San Diego), “Modeling Atmospheric Rivers associated with hazards in SE Alaska”

  • 11:00-12:00 pm: Cryosphere processes (Josh West)
    • Ann Rowan (University of Bergen), “Modelling rapid mass loss from debris-covered glaciers in the Himalaya and associated hazards”
    • Jaakko Putkonen (North Dakota), “Predicting the future ground instability in Alaska”
    • Xiong (Bill) Yu (Case Western), “Simulation of the Effects of Climate Change and Forest Fire on Permafrost Slope”
    • Madison Douglas (Caltech), “Sediment entrainment and slump blocks limit permafrost riverbank erosion”

 Tuesday, May 2, 2023 

  • 8:00-9:00 am: Hydrology and flood routing (Josh Roering)
    • Paul Bates (Bristol), “Combined modelling of US fluvial, pluvial and coastal flood inundation under current and future climates”
    • Brian Yanites (Indiana), “After the Storm: Increased Flood Hazard Persists for Decades Following the 2009 Typhoon Morakot in Southern Taiwan”
    • Francis Rengers (USGS), “Estimating Post-Fire Debris Flow timing with a Rainfall Runoff Model”
    • Guiseppe Formetta (Trento, Italy), “A three-dimensional hydrological model application for simulating critical zone processes”
    • Lauren Grimley (UNC Chapel Hill), “Modeling tropical cyclone induced flooding using ADCIRC+SFINCS”

  • 9:00-10:30 am: Slope stability and landslide processes (Dimitrios Zekkos)
    • Luke McGuire (University of Arizona), “Process-based modeling of runoff-generated debris flows following fire”
    • Ning Lu (Colorado School of Mines), “A Paradigm for Predicting Rainfall-induced Landslides”
    • Ben Leshchinsky (OSU), “Inverse Analysis of Landslide Inventories to Parameterize Distributed Ground Failure Models”
    • Nick Sitar (UC Berkeley), “Efficient DEM modeling of rock slides and avalanches”
    • Dino Bellugi (UC Berkeley), “A multi-dimensional shallow landslide model coupled to critical zone structures and subsurface hydrology”
    • Dalia Kirschbaum (NASA), “Advancing multi-scale landslide hazard assessment with satellite data and machine learning for stakeholder applications”
    • Katy Barnhart (USGS), “Debris flow and landslide runout simulations for postfire and tsunami hazard assessment”
    • David Milledge (Newcastle, UK), “Improving landslide hazard information through better detection, prediction and communication”
    • Alex Gorr (University of Arizona), “A reduced-complexity model for post-wildfire debris-flow inundation”

  • 10:30-11:15 am:  Sediment transport and dispersal in fluvial systems (Brian Yanites)
    • Jon Czuba (Virginia Tech), “Modeling sediment dynamics in river networks”
    • Colin Phillips (Utah State), “High resolution channel response to flooding, wildfire and debris flows”
    • Jeff Keck (WA DNR), “Mass Wasting Runout: A new tool for assessing landslide hazard and potential sediment delivery to the channel network”
    • Angel Monslave (Idaho), “RiverBedDynamics – A Landlab component for computing two-dimensional sediment transport and river bed evolution”

  • 11:15-12:00 pm: Exposure and risk (Corina Cerovski-Darriau)
    • Alex Dunant (Durham University), “Cascading multi-hazard modelling using graph theory”
    • Nate Wood (USGS), “Modeling societal vulnerability and risk reduction to natural hazards”
    • Jocelyn West (Natural Hazards Center, CU Boulder), “Assessing population exposure to landslide hazards in Puerto Rico”
    • JQ Su (Arbol), “Arbol’s hazard and climate models: a commercial perspective”

Part II: We will host a two-day in-person workshop in early fall 2023 that focuses on identifying future research and integration activities that would be needed to couple process models for advancing hazard cascade predictive capability. 

The product of this two-part series will include a white paper and/or review paper that will help inform our NSF Geohazards Center proposal scheduled for submission in March 2024.  We hope to attract a wide array of disciplinary scientists that bring a suite of new and exciting perspectives on modeling hazard cascades. Currently, our center catalyst is focused on the following generalized hazard cascade systems, although we anticipate revisiting and modifying these during the development of our proposal: 

  1.     Fire-storm-landslide-flood (e.g., Montecito, CA 2018), 
  2.     Climate change-thaw-cryosphere mass wasting-aggradation (e.g., Central Alaska), 
  3.     Earthquake-landslide-storms-damming-outburst floods (e.g., Gorkha EQ, 2015).