Thermal beard
The term thermal beard comes from gliding and describes an apparently drooping part at the base of a cumulus cloud, looking like a beard when viewed from cloud height. Where it occurs, it marks the point of the strongest climb and is used synonymously in pilot jargon as "beard" = updraft.
literature
- Roger P. Frey: Cross country flying . BoD - Books on Demand, Norderstedt 2017, ISBN 978-3-7431-4872-7 , pp. 39 ( limited preview in Google Book search).