What is a characteristic feature of Foehn winds?

Foehn winds are characterized by warm, dry air descending the leeward side of a mountain range. As air ascends over a mountain, it cools and loses moisture. Upon descending, this air compresses and warms, leading to the characteristic dry and warm conditions associated with Foehn winds. This descending movement is crucial because it differentiates Foehn winds from other wind types that may be influenced by other meteorological factors.

The warm and dry nature of Foehn winds contributes to increased temperatures and decreases in humidity on the leeward side, which can significantly alter local weather conditions and create a fire-prone environment. Understanding this mechanism is vital in fire behavior analysis, especially in regions where Foehn winds can exacerbate wildfire conditions.

In contrast, some of the other options describe features that do not apply to Foehn winds. For instance, these winds are not cool and moist; instead, they are notably warm and dry. They can occur at various times of the year, not just in the winter months, and their speed and direction can vary significantly, lacking the consistency described in one of the options.