Additional influences and information

Extreme fire behaviour because a convection column has formed

Convection is the transfer of heat through the movement of heated air.

Most of the heat transferred from a bushfire is from convection currents of hot air. This process forms a convection column of rising hot air and a smoke plume above the fire.

The convection column can carry ash, embers and pieces of burning fuel, as well as preheating the vegetation above the fire (higher shrub layers and tree canopies). Large convection columns can produce severe weather events including cyclonic wind and lightning.

Key consideration for planning decision making:

The conditions in the broader landscape around a proposal influences the size to which a convection column can grow and in essence the destructive potential of a fire.  The conditions include the topography and the extent and ability of fire to run through vegetation.

Therefore, the planning system requires the bushfire hazard to be assessed at many scales. This allows for planning proposals to fully understand and respond to the bushfire risk.