Never fished eufala but a lot of the lakes I fish, the creeks will hold Shad all winter. When the afternoon sun hits the creeks they can warm up quicker. I would drive into several creeks and compare their water temps to main channel water temps. I net a lot of Shad for bait and can almost always get them in creeks. Sometimes when it's real cold the creeks are frozen or close to it and the main channel is warmer. Like posted above, some bass never Leave the main and some never leave the creeks. Also, on eufala you probably have gizzard and threadfin Shad. The threadfin die off when it's super cold but the bass will still eat them while they are dying and dead. The gizzards will tolerate much colder water and don't seem to die off nearly as often