ERF-Fire

This repository holds the documentation for mapping wildfire models to ERF, as well as links to the models themselves.

A wildland fire and the atmosphere drive each other: the wind spreads the fire, and the fire's heat drives the wind. The code is split along that line.

Part	What it does	Where it lives
Fire coupling	The atmosphere side: where the fire grid sits, what the fire is handed each step, and how its heat, water vapour and smoke enter the atmosphere	erf-model/ERF, Source/FireCoupling
Fire engine	The fire model: spreads the front and reports the heat it releases	Its own repository, which holds ERF as a Git submodule

ERF contains no fire engine of its own. An engine plugs into the coupling through one interface, and ERF needs no change to add one.

Every fire engine uses one repository layout. The engine's repository holds ERF as a Git submodule, pinned to an ERF release or commit, and builds its executable against it. The engine's cases and tests live in the engine's repository, not in ERF, so ERF's CI runs only ERF's own tests. FLARE and LSFIRE both use this layout; FLARE runs its tests in its own CI.

A change an engine needs in ERF goes to erf-model/ERF as a pull request. The engine then moves its submodule to an ERF commit that contains it.

Documentation

The documentation is published at erf-model.github.io/ERF-Fire. It is built with Sphinx from the pages in docs/. The Markdown pages below also read on GitHub:

• Fire–Atmosphere Coupling in ERF: the coupling components in ERF, how to build them, their inputs, and what an engine must provide.
• FLARE: the engine, how the FLARE repository uses ERF as a submodule, and what it holds besides the engine. The FLARE model documentation and its inputs, copied from the FLARE repository, are on the published site under FLARE.
• LSFIRE: the level-set engine, its ERF adapter, repository layout, and coupled test cases.
• Tutorials: placeholder; the tutorials are not written yet.

To build the pages locally:

python3 -m pip install -r docs/requirements.txt
sphinx-build -W --keep-going -b html docs _build/html

then open _build/html/index.html.

Fire models

Model	Repository	Selected with
FLARE (Fire-Line Advancement and Reaction Engine)	erf-model/FLARE	erf.fire.engine = flare
LSFIRE (level-set wildland fire spread model)	erf-model/LSFIRE	erf.fire.engine = lsfire

Each model's team maintains the description of its own model.

Names

Until October 2026 the native fire model was developed on the ERF-Fire branch of hgopalan/ERF. Its coupling code then moved into ERF, and the model became FLARE. In this repository, "ERF-Fire" means the fire coupling in ERF and this documentation, not one fire model.