The Extended Attack Assessment Index (EAA) evaluates fire control difficulty after initial suppression efforts have failed to contain a fire. Where the Initial Attack Assessment (IAA) focuses on the first one to two hours post-ignition, the EAA addresses the extended attack phase, when a fire has escaped or is at risk of escaping initial containment and requires a sustained, coordinated response.
The EAA was developed primarily for fire agencies and is intended to support resource prioritization, communication of wildfire potential across an incident, and operational decision-making during the extended attack phase. Higher values indicate greater fire activity, increased suppression difficulty, and elevated potential for a fire to become a major incident. EAA is a continuous variable with no theoretical upper bound, but is reclassified into a 1 to 5 scale for interpretability
The key distinguishing factor of the EAA is its inclusion of pyroconvection effects (the atmospheric instability and convective processes that can develop as a fire grows and generates its own weather). These effects can dramatically accelerate fire spread, alter fire behavior in ways that defy surface-level predictions, and significantly increase risk to suppression resources. Because pyroconvective conditions are not captured in simpler fire behavior indices, the EAA provides a more complete picture of conditions that determine whether extended attack operations are likely to succeed.
The EAA draws on a range of inputs: fuel type and loading, drought conditions, meteorological variables, fuel physiological responses to environmental stress, and atmospheric instability. Technosylva uses a machine learning approach to analyze each variable's contribution to the index and improve model performance over time.