Ursa

Ursa is a python tool for the setup, management, and analysis of postfire debris-flow runout simulations. Ursa provides (1) a set of python functions that accomplish each phase of a hazard assessment workflow and (2) a Snakemake snakefile that uses the python functions to run the entire workflow.

Ursa is intended as a flexible tool for a particular purpose. It is not intended as a general or extensible software package.

Warning

Before using ursa, review the Disclaimer and Limitations page.

Using the documentation

The documentation contains four elements. Most users should start with the User Guide, which provides an overview of what ursa does, the computational resources it needs, and the information it produces. Should a user find that they need to run ursa, the next portion of the documentation that may interest them is the Getting Started section, which describes the platform requirements and installation instructions. After installation, we suggest running the example case study for the 2016 Sherpa Fire described by the example application.

Most use-cases are accommodated by modifying the ursa config.yml file. However, for those with a need to add functionality or change the workflow, the API, and other development resources will be of interest.

Citation

If you use ursa in a publication, cite it as follows

Barnhart, K.R., and Fruge, A.S., 2026, ursa - Python library for postfire
debris-flow runout hazard assessments and research, version 1.0.0: U.S.
Geological Survey software release, https://doi.org/10.5066/P15CKL9J.

Bibtex

@misc{barnhart_2025,
    title = {ursa - Python library for postfire debris-flow runout hazard
             assessments and research, version 1.0.0},
    author = {Barnhart, K.R. and Fruge, A.S.},
    url = {https://code.usgs.gov/ghsc/lhp/ursa},
    year = {2026},
    doi = {10.5066/P15CKL9J}
}