What typically happens to relative humidity (RH) when foehn winds begin?

When foehn winds begin, relative humidity typically drops. This phenomenon occurs due to the warming effect associated with these winds. As the air descends on the leeward side of a mountain range, it compresses and heats up, which reduces its relative humidity. The warmer air can hold more moisture, leading to a decrease in relative humidity levels. This drop in RH can exacerbate fire conditions, as lower humidity means drier air, which can enhance fire behavior and spread. Understanding this relationship between foehn winds and relative humidity is crucial for fire behavior analysis and risk assessment in wildland fire management.