What consequences can ground effect have on the UAV in stationary flight?

Question

Question EASA Drone Quiz - Flight performance and planning

QuizVDS · Accepted Answer

Freezing rain

QuizVDS · Answer

None of the answers is correct

QuizVDS · Answer

The ice that slowly accumulates on the airfoil and that we can remove

QuizVDS · Answer

Ice slowly accumulates on the airfoil and we cannot remove

Id 160 - EASA Drone Quiz – Drone Pilot Certification - What consequences can ground effect have on the UAV in stationary flight?