https://images.fiberglassflyrodders.com/u/1/pi/kXtQsW-9c~yellerhammer.jpg

This is a pic (sorry for the poor quality of the photo, but I am definitely not a photographer) of my version of the Yellar Hammer wet fly which is a Smoky Mountain creation. It works. The trout in the Park streams will hit it hard. I'm not sure what it is supposed to represent (possibly a stone fly nymph?) The fly was originally tied with the the wing feathers of the Yellow Hammer Flicker. The feathers of this bird are now illegal to possess and it is illegal to kill one. There are many substitutes for the flicker feathers that work very well. My version involves the died yellow of a duck quill.
Hook: any nymph hook size 6 down to about a 14. I usually add a copper bead and wrap the hook with lead (or other) wire.
Thread: yellow tying thread
Tail: any reasonable hair or hackle
Body: Usually yellow chenille or yarn, but other colors work well and provide a little contrast with all the yellow.
Hackle: I soak a died yellow duck wing quill for 15 minutes or so, usually by wrapping in wet paper towel. Starting at the tip end of the feather I trim off some of the feather on both sides. Tie the tip at the tail end of the hook and wrap toward the eye. Tie off when the eye or bead is reached.
Joe

It might work up there. Tie some up and give it a shot.
Joe

Whrlpool, I can't remember exactly what I tied the tail with; it was either deer hair or squirrel tail, depending on what was readily in reach on the tying bench. Sometimes I use more yellow such as duck quill. The tail material doesn't really matter too much. The only other version I have tied is what is called the "crow fly" which is another local mountain fly going way back. It is tied in black with some kind of black wing feather for the hackle. Originally crow feathers were used.
Joe