What happens to air currents when flying over hills or mountains?

When flying over hills or mountains, the behavior of air currents can significantly change due to the interaction of airflow with the terrain. As air moves over elevated landforms, it is disturbed and can create turbulence, especially on the leeward side of the hills or mountains. This area, known as the "lee" side, can experience stronger, unpredictable winds, which are often turbulent and can lead to downdrafts or rotor effects. These phenomena can pose increased risks for lighter-than-air craft, making this choice the most accurate.

Navigating the leeward side requires increased caution because pilots may encounter unexpected turbulence and severe changes in wind direction, potentially affecting stability and control. Therefore, understanding these air currents is crucial for ensuring safety while flying in mountainous regions.