Propagation
Wildfires spread through a process called propagation, which involves the movement of flames across a landscape from one fuel source to another. The fire can spread in several ways, primarily through three methods: convection, radiation, and direct flame contact. Convection occurs when hot air and gases rise, carrying embers that can ignite new fuel sources far from the original fire. Radiation transfers heat to nearby combustible materials, causing them to catch fire without direct contact. Direct flame contact happens when flames leap from one burning object to another, igniting surrounding vegetation. The speed and direction of fire propagation depend on how quickly these processes can transport heat and embers across the area.
Several factors influence the likelihood of wildfire propagation. Weather conditions such as high temperatures, low humidity, and strong winds can significantly accelerate the spread of a wildfire, as they provide the necessary heat and oxygen to fuel combustion. Wind, in particular, can carry embers over long distances, igniting new fires in areas far beyond the original blaze. The type, dryness, and arrangement of fuels also play a critical role; dry vegetation and dense, continuous fuel beds create ideal conditions for fast-moving fires. Additionally, the terrain can impact fire behaviour; fires tend to spread more quickly uphill due to the natural upward movement of heat and smoke. Human activities, such as poorly managed land or the presence of flammable structures, can further increase the likelihood of rapid fire propagation.