What is the typical behavior of fires on South-facing slopes?

The typical behavior of fires on south-facing slopes is characterized by their tendency to spread quickly due to high temperatures and low humidity. This phenomenon occurs because south-facing slopes receive more direct sunlight throughout the day, leading to increased temperatures and reduced moisture in the fuels—such as grasses and shrubs—found in these areas. The combination of elevated temperatures and lower humidity creates optimal conditions for fire ignition and rapid spread.

As the sun heats the slope, the moisture in the vegetation decreases, making it more combustible. In wildfire behavior, this is critical as vegetation with lower moisture content ignites more easily and burns more fiercely. Therefore, south-facing slopes are generally known to be more fire-prone compared to other slopes that might receive less sunlight, contributing to the potential for faster rates of spread and more intense fire behavior.