The St. Joe is not much unlike any other famous Western trout stream like the Madison, Gallatin or Henry's Fork this time of year. The most productive winter fly fishing technique is to drift nymphs near the bottom in any good holding water. Fish do not feed aggressively this time of year. Their strike zones have decreased greatly in size, but you have the possibility of some good action if it is a solid drift where the trout want it. You may need to almost pop them in the head to get them to take. If you are partial to streamer fishing, try a green or black pattern and slow your retrieve to about 5/8 normal speed. Again, run your streamers through any solid holding water and be patient.
Many of the fish have moved down stream from their usual holding areas during the summer and fall months. Try fishing the stretches down stream from Prospector and Shookum creek. Dress warm and Happy Fishing!!