If it is a really rare coloration for your area, it might be someone's exotic pet that either escaped or was released. Hell, I wrote about this in early Spring in this forum, we had a wacky woman who claimed a Cobra bit her in a mall parking lot in the snow! DNR knew she was lying, they went and investigated her and she had another venomous snake, a Rattlesnake, in her house without the proper permit. So, anything is possible. A woman died years ago unpacking rattan furniture for a furniture store, bit by a Krait. Anything is possible.
As for the continuing "debate" about snakes being harmless and they're more afraid of you than you are of them and the rest of the propaganda...
If a snake is hungry, if a snake is feeding, if a snake is ready to mate, if a snake is ready to shed, is shedding or has just shed and if it is extremely HOT, they can be aggressive. They get lethargic from the cold and being stuffed to the gills with something they ate. I have not only observed snakes and know people I trust who have observed this behavior, it also stands with constrictors who are pets.
Where I grew up, black snakes, racers, and blue racers, had a really bad reputation for not standing their ground but coming right after you to give you a nasty bite. Sometimes the kids were pestering it, sometimes they were not.
Mannlicher has a thread going where he had a nice little camping trip down in Southwestern Virginia. A short distance from where he was, I watched a good-sized Timber Rattler sunning himself on top of a rock outcropping about as large as a VW Beetle. It was pretty neat because it was mid-November, if I remember correctly, but it was chilly and there was a smidge of snow on the ground in places. If they are layed up in under rocks like that and the sun heats them up, strange things can happen, you see. So, conventional wisdom is one thing and reality is another, watch where you put your hands even when you think it is otherwise okay to do so. If you are in Rattler country and the rocks are out in the sun, soaking that heat up. Don't just think because it is late Autumn or early Winter that everything is instantly okay.