Wildland Firefighting Practice Exam

When are Dust Devils most prevalent?

1. Early morning

2. Midday

3. Late afternoon

4. Evening

The correct answer is: Midday

Dust devils are most prevalent during midday. This phenomenon occurs primarily because, at this time, the ground has had the maximum amount of sunlight exposure, resulting in higher surface temperatures. As the ground heats up, the air just above it also warms up, becoming less dense and rising quickly. This upward movement of hot air creates a low-pressure area, which can draw in cooler air from surrounding areas. This interaction can lead to the formation of a rotating column of air, known as a dust devil. Additionally, the midday conditions typically include strong solar heating coupled with low wind speeds, which are conducive conditions for dust devil development. In contrast, during early morning and evening, the ground is cooler, which minimizes the temperature differential that drives the formation of these whirlwinds. The dynamics that favor dust devil formation are less pronounced, making midday the most likely time to observe them in action.