What is typically observed directly above a mountainous area?

When flying above mountainous areas, rotor clouds are a common phenomenon. These clouds form as a result of orographic lift, which occurs when airflow is disrupted by the terrain. As air ascends the mountains, it can create turbulence and rotating air currents in the region just above the peaks. This turbulent airflow often manifests as rotor clouds, which are characterized by their swirling, horizontal formations that signify significant turbulence and updrafts.

Other options, while they might seem plausible, do not typically represent the atmospheric conditions over mountainous regions. Clear skies may occur at times, but they are not a definitive or typical observation linked to mountainous terrain. Stormy weather can occur, particularly in the vicinity of mountains, but it does not specifically represent the direct impact of the terrain itself. Similarly, calm conditions are less frequent in mountainous regions due to the complex airflow patterns created by the terrain, which often leads to varying weather phenomena, including rotor clouds.