Mountain waves is an atmospheric phenomenon that consists in the existence of atmospheric waves caused by orographic forcing = mountains. Atmospheric waves are imperceptible to our eyes, and constitute an increase danger to aviation.
Just like in the ocean, atmospheric waves carry mass and energy through its propagation. Mountain waves create at the zones adjacent to mountains regions of elevated turbulence that can literally crash planes into ground or make them go up and down through wave forcing.
It’s difficult for many human beings to imagine that the atmosphere holds waves, because the atmosphere is invisible to us. It would be similar to a fish trying to perceive internal waves in the ocean, because sea water is invisible to fish, just as what we call “air” to is invisible to us. However, it exists and it’s not “nothing”. As a fish can see air out of water and we can see water out of air, we can perceive waves in other mediums that are not invisible to us: water. When you look at the sea you can see waves on it, and in it. However, you cannot perceive waves in the atmosphere, because it is invisible to us and therefore its waves are too.
Nevertheless, waves in the ocean and atmosphere are complex transport of mass and energy phenomena, with complex differential equations defining them.
Because mountains are orographic forcing into the atmosphere they cause the flow of air in their surroundings to fluctuate, creating well defined atmospheric waves. These waves have crests and throughs and create zones of increased turbulence in the vicinity of the mountain. These waves are particularly dangerous to aviation, and have been the cause of many plane crashes. What happens is because they are an added forcing to a plane they either throw the plane up and down if not that pronounced, or they can literally force a plane to the ground if in the presence of pronounced mountain waves.
In aviation, mountain waves and the study / research of them is of extreme importance. Most planes that crash near mountains have been in a way forced by mountain turbulence that is more often than not related to mountain waves. If mountains are near the ocean, planes can crash into the sea. When a plane crashes close to a mountain or a mountain range, it’s important to research if mountain waves haven’t been the cause of such crash.
Mountain waves are unpredictable and imperceptible, therefore severely dangerous for aviation close to mountains. Experienced pilots and aviators have some experience and can perceive them in their acquired experience and wisdom. New pilots can have studies and know how to identify mountain waves as well, even if they do not own as much experience as more advanced professionals in aviation.
It’s very important to know about mountain waves conditions, if possible and available, before flying in areas where mountains are present, specially tall mountains or mountain ranges.
Sara Vanessa Wxx