Wildfires Hazard: Introduction

Fire is a powerful force – out of place, out of proportion, or out of control, fire poses a serious threat to human life and property, and to our natural resources. Within just seconds a spark or even the sun’s radiant heat can set off an inferno.

Wildfire is one of the most destructive natural hazards known to mankind. It is a term given to any unwanted and/or unplanned fire burning in forest, shrub or grassland. A wildfire can quickly spread, consuming thick, dried-out vegetation and almost everything else in its path. In a seemingly instantaneous burst, wildfire has the potential to overtake thousands of hectares of surrounding land, threatening the homes and lives of many in the vicinity.

Compared with some hazards, such as earthquakes and volcanoes, wildfire occurrence and behaviour can often be predicted, and therefore adverse effects to humans and the environment can be minimised. Despite the relative simplicity of the combustion process by which a fire is formed, the biogeophysical science behind wildfire behaviour and prediction requires a multidisciplinary approach. A solid understanding of the chemistry and physics of fires, as well as background information on the topographical and meteorological features of the region at risk and characteristics of the fuel is essential.

In this module we will investigate the basic elements of fire: fuel, oxygen, and heat, as well as the factors that effect wildfire behaviour.  The impacts of wildfires on ecosystems, geosystems, atmosphere, and society will also be discussed.  Finally, we will look at various prevention and protective measures currently used to mitigate wildfire occurrence and its effects, followed by a brief look at New Zealand and overseas case studies.