As Flows on the south fork drop to around 2,500 cfs out of Palisades dam, we are starting to see what the wade options are going to look like during the first part of the fall and winter months. Talk is that the river flows will be re-evaluated after the 1st of December, in which case will most likely be increased. This can mean some good news for the boat fisherman, as float will take less time to complete, and you will be able to cover more water. For the wade fisherman these changes will have more effect than in winters past where we are use to seeing the flow around 1,200.
As for the current conditions, the South Fork streamer fishing has been pretty good on cloudy days, and even on some random sunny days as well.. Color is the name of the game her, so bring your sparkle, white, yellow, tans, and olives. Some days the darker colors really do well, but overall this river seems to respond best to brighter, and flashier patterns.
Dry fly fishing is good, but as per usual, the cloudy days reign supreme. Fish size 18-20 BWO patterns, and 18-20 midge patterns. Back eddies are a great option for finding fish feeding on the surface.
Try fishing nymphs from the boat set at 5-6 feet for floating. I generally run much deeper when standing on a riffle, and in most cases would recommend the same. Use a small rubberlegs, a san juan work, or a big caddis pattern, trailed by a small beadhead mayfly nymph in the size 14-18 range. If in doubt, a red Zebra midge will usually get the job done as a trailer fly.
As for fishing on the main (Idaho Falls to American Falls), the streamer is the main game here, as browns are in their pre spawn, and are on the streamer bite pretty well. Patterns I usually do best on are Tan or natural peanut envys, and sex dungeons, but like anywhere changing pattern and color can sometimes make the difference.
American Falls is running at 2,100 cfs, and the wade fishing is much tougher than usual. The water had changed colors the last time I was there a couple days ago, leaving the visibility at roughly 2′ tops. I would recommend that anybody planning on wading there to bring a wading staff so they can poke around before they step. Flies that are fishing well is pretty much any beadhead nymph in a size 12-18, and dead drifted streamer patterns. If your into dry fly fishing, you can fish blue winged olives and find success.