Wildland Firefighting Practice Exam 2025 – All-in-One Guide to Master Your Firefighter Certification!

Winds that occur when the sun sets and surface cooling begins are defined as downslope winds. These winds typically happen because the air, having been heated during the day, rises as the surface loses warmth after sunset. As the cooler air descends from elevated areas, it creates a flow of downslope winds. This phenomenon is particularly common in mountainous regions where cooler air descends into valleys, following the logic of cold air being denser than warm air.

Understanding downslope winds is essential for wildfire behavior, as these winds can push flames and embers downhill, potentially spreading a fire more quickly in the evening hours. This contrasts with upslope winds, which occur during the day when the sun heats the surface, causing the air to rise. Thermal winds and trade winds are related to different atmospheric dynamics and are not specifically linked to the cooling effects that occur at sunset.