Mountain wave

{
  "id": "MLC-T-AVN-000638",
  "term": "Mountain wave",
  "field": "Aviation and air traffic control",
  "definition": "Mountain waves occur when air is being blown over a mountain range or even the ridge of a sharp bluff area. As the air hits the upwind side of the range, it starts to climb, thus creating what is generally a smooth updraft which turns into a turbulent downdraft as the air passes the crest of the ridge. Mountain waves can cause significant fluctuations in airspeed and altitude with or without associated turbulence.",
  "references": [
    "AIM",
    "FAA Pilot/Controller Glossary"
  ],
  "url": "https://mlchart.com/terminology/aviation/mountain-wave/"
}