Canadian Fire Weather Index System

Canada Buildup Index (BUI) Map

BUI combines Duff Moisture Code and Drought Code to provide a relative indication of the total amount of fuel available for combustion in the FWI System's standard fuel complex.

Natural Resources Canada · CWFIS
Buildup Index (BUI)

Loading the official BUI layer…

What it means

How to interpret BUI

Higher BUI values generally reflect greater cumulative drying and more fuel potentially available to burn. BUI is combined with Initial Spread Index to calculate Fire Weather Index.

Important limitation

Fire weather is context, not a local prediction

BUI is not measured fuel loading at a site and does not determine fire size, severity or suppression outcome on its own.

How BUI fits into CFFDRS

Canada's Fire Weather Index System connects weather observations to fuel-moisture codes and fire-behaviour indices. FireRadar keeps each component separate so users can see what is actually being measured or derived instead of receiving an opaque combined risk score.

Use official operational guidance for decisions

CWFIS products are broad national fire-weather guidance. Provincial, territorial, Indigenous, municipal and Parks Canada authorities remain responsible for operational fire danger, restrictions, wildfire response and emergency decisions.

Official methodology and source

FireRadar renders the official Natural Resources Canada CWFIS layer directly and preserves the upstream symbology. It does not interpolate a value when the source is unavailable or transform this component into a FireRadar property-risk score.