@JeremyECrawford is a creature with reach (or reach weapon) at disadvantage melee attacking a prone target that is 10ft away (PHB 292)
— Latreille Yannick (@laty2212) May 22, 2017
The prone condition imposes disadvantage on any attack roll that originates from an attacker who is more than 5 ft. from the target. #DnD https://t.co/II4XZslk4Q
— Jeremy Crawford (@JeremyECrawford) May 22, 2017
@JeremyECrawford does the prone condition allow a rogue to use uncanny dodge against an attack?
— Jim Miller (@pokereleran) May 22, 2017
No rule prevents a prone character from using Uncanny Dodge. #DnD https://t.co/UHqeaSpyMl
— Jeremy Crawford (@JeremyECrawford) May 22, 2017