I too have a bit of a worm problem at different times of the year. They get on my concrete carport. They do that when we have had much rain, and the soil is totally saturated. They are merely heading to higher ground to keep from drowning. There is really nothing that can be done, other than trying to provide some drainage, so they won't be forced to go to higher ground.

Mine end up dying on the carport, as I don't go out and get them and put them somewhere where they can survive. Possibly they are near death or dying by the time they find the higher ground. I have thought many times that I should gather them while they ar still alive, and put them in the garden spot, or a flower bed, but just have not made or taken the time to do that when it is raining out, or shortly after it quits. Subsequently, most die, dry out, stick to the concrete, and then have to be scraped up later. They won't just sweep off...sigh...

I've not noticed the color of mine particularly, or that they stink, but then mine are in the open air. Dead worms do stick though...remembering many a bait box with dead worms in it.

Sue