Never been to Blue Ridge myself but big black cats are one of those things that keep cropping up all over the place and the authorities just keep batting it away. We get the same thing up here in Yorkshire - "escaped melanistic leopard" is usually what people settle on, and honestly that explanation holds more water than most officials will admit.
What did it look like when you saw it? Size relative to a dog is usually the best benchmark people use. The gait matters too, big cats move completely differently to dogs, theres a kind of fluid low-to-the-ground quality to it that people always mention after the fact.
Would love to hear more details from anyone who was out that way last summer. Sightings clusters are worth paying attention to, if multiple unconnected people are reporting the same area within a short window thats not nothing.