A couple of weeks ago, I saw a large Bald-faced Hornet nest being whipped around by the wind way up a tree overlooking the Dell Water. More recently, I looked up and saw nothing.
A clump of hornet paper stuck on a bush was my first clue. I scanned the ground up the slope with greater care.
Ah-ha! Stripped of the surrounding layers of paper, here were four levels of paper comb.
Remains of larval hornets were scattered about.
Dead worker, dead larva, live fly, and a pretty active ant. Temps were in the 40s.
Looking closely at the paper, you can see the wood fibers that make it up.
These incredible constructions are only built for one season. Only the queen over-winters. The nests rarely survive the winter. This one came crashing down. 
But this one was collected. Flatbush Gardener removed this one from a neighbor’s shrub, with permission from the neighbor. This was one of the biggest I’ve seen. (Party lighting here, sorry.) Notably in a shrub instead of way up in a tree. I’ve seen them in young street trees, too, barely above eye-level. There are a good number of these nests in Brooklyn, but the hornets themselves are a bit elusive. I mean, they are obviously all over, but you don’t see them everyday.
Similar experience with a nest in a tree on the dam (where it shouldn’t be) of the pond at my Ozark cabin. One season, so active, I didn’t dare walk across the dam. The next season, quiet (upon cautious approach), and then the next season, gone altogether. (Time to remove that tree!)
I wonder if they’ll use the tree again? I wonder how the queen chooses a place? I’ve also seen them on the sides of structures.
That was two years ago, and they hadn’t returned to it in the subsequent year. Nor did they return to a tree across the lake in a later year. And I’m still not eager to go to a part of the forest where I saw them coming up out of the ground!