They are swarming steadily in North Arkansas too. Last week when we had the cold snap for a few days I met my first mean swarm. A guy called me about a swarm about 12 feet off the ground in a plum tree that had been there for a couple days.
As soon as I climbed up the step ladder they attacked. No head butting, No warning, just stinging. I got nailed 5 or 6 times getting back down the ladder and had to put on a veil,jacket and gloves to get them in the box.
I had a frame of honey and some drawn comb in the box and they started in on the honey immediately. I left them overnight and picked them up the next morning. I guess they were just hungry and that made them irritable, Since I've brought them home they've been as gentle as any hive I own.