WUI

WUI stands for Wildland-Urban Interface, a form of land where wildland vegetation and human development meet or intermingle. It is a dynamic zone rather than a fixed boundary, defined by factors such as vegetation type and density, topography, climate, and land-use patterns. The WUI is a focus of wildfire risk management because fires originating in natural fuels can threaten homes, infrastructure, and lives, and suppression efforts are complicated by the proximity of structures to flammable vegetation.

Two commonly used classifications describe the mix of structures and fuels: the interface, where development abuts wildland vegetation, and the intermix, where buildings are scattered among vegetation with limited gaps. The interface generally presents higher risk of direct flame contact from adjacent fuels, while intermix scenarios face continued embers and radiant heat hazards.

Mitigation strategies in WUI areas include land-use planning, building codes and ignition-resistant construction, and creating defensible space around properties by removing or spacing flammable vegetation. Fuel treatments, prescribed burning, and landscape management reduce wildfire intensity. Communities often develop wildfire protection plans, participate in programs such as Firewise USA, and implement evacuation and emergency response planning.

Climate change, expanding housing development into wildland areas, and increasing fire weather contribute to growing WUI risk. Accurate mapping and risk assessment inform policy and funding for fuel reduction, infrastructure hardening, and community engagement to improve resilience to wildfires.