What condition causes anabatic winds to form?

Anabatic winds typically occur when the sun heats the slopes of mountains or hillsides. As the terrain warms, the air directly above it also heats up. Warm air is less dense than cooler air, causing the heated air to rise up the slope of the mountain. This upward movement creates anabatic winds, which are characterized by the flow of warm air ascending along the mountainsides.

In contrast, while cold air settling on mountains could contribute to other wind patterns, it does not create anabatic winds. Warm air flowing from valleys is also a different phenomenon known as katabatic wind, where dense, cold air moves down into the valley. High-pressure systems can influence wind patterns but are not directly related to the specific conditions that lead to anabatic winds. Therefore, the correct understanding lies in recognizing the role of direct sunlight heating the slopes, which is fundamental in the formation of anabatic winds.