Living in a mountainous area we can get some unique clouds around here. During the winter months its not unheard of for spaceship like clouds to form. Especially on the leeward side of the mountains. These spaceship like clouds can be a sign that a storm is coming and can be called Sierra Wave Clouds. They can also be called lenticular clouds because of their smooth appearance and lens shape. While most clouds move, these clouds are stationary and can either be short lived or last for hours.
So how do they form? You need a few ingredients to get them to develop. For starters you need enough moisture, as well as stable air. Stable air is air that cannot rise on its own. The air is basically moving west to east, hits the mountains and creates waves on the other side of the mountain. This is similar to throwing a rock in water, and ripples surrounding it. Wave clouds form when the air rises, cools and condenses. All be it rare, lenticular clouds can also form when a front moves through.
Wave clouds are a sign of turbulence, which is not the best weather for flying. If you see a wave cloud, expect some delays and cancellations. Depending on the storm, winds can stray strong after the wave cloud has dissipated. They are common in the winter, when upper level winds are usually the strongest.
