I've seen that before, in old pine stumps where the bark is loose. When a colony of wasps finish their breeding season and abandon their nest, the bred females and a few males scout an area to find a place to go into hibernation. The initial gathering is pre-hibernation. The males will very quickly die off and only the bred females will survive for nest spring's nest building and colony re-population. Each of those bred females is capable of starting a new colony next spring. The social aspect of the colony is that after the last brood has exited the paper nest, the wasps just gather around something that provides shelter, but are pretty docile compared to when they were nesting and protecting their nest and young that are inside, in larval stage. There might just be a few, or hundreds from different nests, and might not even all be the same species. I've seen it also in equipment, like in the knuckle of my old backhoe boom. They would just hang out there, flying about as I operated the backhoe and settled back down in it when I would stop.
In the stumps I saw, I could peel the loose bark back in cold weather, and the red wasps just fell out onto the ground. Not dead, just immobile because of the cold and their metabolism has slowed down to a crawl. Only 1 or 2 actually able to fly.
At my sister's home, hundreds, maybe thousands hang out this time of year under the eaves of her house, and as soon as the 1st cold spell comes, they go in thru the ventilated soffits and spend the winter in her attic hibernating.
