Two weeks ago (or so), on the 28th, I saw the first few hickorynut husk bits on the sidewalk. Then, the very next day, Sunday the 29th, I heard nut and husk bits falling everywhere and they were abundant on the sidewalks and streets.
And, this holiday weekend, drifts of nut shell and husk shards. As hickories are taxonomic cousins to walnuts, the husk fragments become black and nasty after a few days.
More autumn evidence.