2026 ATF Workshop

Workshop I: Post-Wildfire Flood and Debris-Flow Hazard Assessment Using HEC-HMS and HEC-RAS: 2025 Eaton and Palisades (Los Angeles) Wildfires Case Study

1:00pm - 5:00pm, Monday, 6 April 2026 

Suncadia/Cle Elum, WA

Training Description:

This hands-on workshop will demonstrate an integrated hydrologic and hydraulic modeling approach for assessing post-wildfire flood and debris-flow hazards, using the 2025 Eaton and Palisades wildfires in Los Angeles County as a case study of a coordinated, multi-agency emergency management response. Recent enhancements to the U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center (HEC) tools, HEC-HMS and HEC-RAS, now enable explicit simulation of debris yield and flow, as well as the non-Newtonian fluid behavior associated with mud and debris flows.

Objectives:

The workshop will combine:

1. Informative lectures on watershed-scale sediment transport, post-wildfire hydrologic response, and debris-flow processes, with emphasis on how these processes are represented in HEC-HMS (debris yield/flow computation) and HEC-RAS (non-Newtonian debris-flow hydraulics).
2. Hands-on training in building and applying coupled HEC-HMS and HEC-RAS models for post-wildfire conditions, including watershed and burn-area characterization, debris-flow parameterization, model setup, calibration, and scenario-based hazard assessment.

Participants will be able to configure, run, and interpret HEC-HMS and HEC-RAS models for post-wildfire flood and debris-flow analysis, directly improving local preparedness through their enhanced ability to support risk assessments, emergency planning, and debris-flow management. Beyond technical skills, the workshop will also outline key programs and authorities enabling partnerships with the USACE, further strengthening collaborative efforts to bolster local preparedness efforts.

This workshop is intended for engineers, hydrologists, geologists, and emergency management professionals seeking to apply state-of-practice debris and sediment modeling tools to real-world post-wildfire hazards. Instruction will be led by a multi-disciplinary, interagency team of experts from the Hydrologic Engineering Center (HEC), USACE Los Angeles District, and the California Department of Water Resources, ensuring a comprehensive and practical learning experience. A detailed agenda will be provided prior to the event.

It is recommended that you use this specific version of HEC-HMS for this workshop and HEC-DSSVue version 3.4.15 for the class. You do not need administrative privileges to install HEC-HMS and HEC-DSSVue. Download HEC-HMS special potable testing version 4.14 beta (HEC-HMS-4.14-beta.1-win-x64.zip) only for this workshop. Download HEC-DSSVue potable version 3.4.18 from this page, https://www.hec.usace.army.mil/software/hec-dssvue/downloads.aspx. Then use 7-zip and unzip the files to the C:\Programs directory on your computer (you should have a folder named HEC-HMS-4.13-beta within the C:\Programs directory). Then you can pin HEC-HMS.exe and HEC-DSSVue.exe to your taskbar and open these programs by clicking on the icons. You do need to install latest version of HEC-RAS 6.7 beta 5 using the app portal - https://app-portal.usace.army.mil/ESD/Loader.aspx?q=webext&f=sccm or from this page, https://www.hec.usace.army.mil/software/hec-ras/download.aspx.   

Workshop Details:

• Time:  Monday, 6 April 2026, 1300 – 1700 (PDT)
• Location: Owens B
• Coordinator: Jang (Jay) H. Pak, Ph.D., P.E., Sr. Research Hydraulic Engineer, US Army Corps of Engineers, Hydrologic Engineering Center
• Contact: jay.h.pak@usace.army.mil
• Instructors: Dr. Jay Pak ,Mr. Jose Paredez, Dr. Moosub Eom, Mr. Christopher Stanton, and Ms. Megan Whalen
  
  

Workshop Agenda:

Most Recent 4-Day Workshop (March 30–April 2, 2026):

2026 Post-Wildfire Debris Flow Modeling Application Workshop using HEC-HMS and HEC-RAS (SET Fund)