Ground Effect 3 : Reaction of a rotor downdraft against the ground surface, forming a "ground cushion" that increases lifting capability of that section of air
National Wildfire Coordinating Group (NWCG), Glossary of Wildland Fire Terminology, NWCG Program Management Unit, National Interagency Fire Center, Boise, ID, USA 2014. http://www.nwcg.gov/pms/pubs/glossary/pms205.pdf, (For Fr - Amer) {45}