Fly Fishing Stream Conditions Report: Henry's Fork - Box Canyon

This year: Fishing on the Box Canyon stretch of the Henry's Fork has been good, with flows holding around 600 CFS. These flows are just high enough to allow for floating with a hard boat. Anglers should focus on nymphing, especially with larger stonefly imitations. Keep an eye out for significant hatches of Salmonflies and Golden Stones. Caddis and Blue Wing Olives are also present, and you'll find plenty of March Browns as you approach the Last Chance boat ramp. For nymphing, try dropping a size 6 black rubber leg with a size 16 Mic Drop.

Prior years: Fishing in the Box Canyon is generally good this month. Flows have varied significantly, starting low at 359 cfs and increasing to 1600 cfs. At lower flows around 359-450 cfs, the canyon can be a bumpy ride, and hard-sided boat bottoms may suffer. As flows increase to 750 cfs, the ride becomes less bumpy. Flows around 1400 cfs are comfortable for drifting and indicator nymph fishing. At 1600 cfs, the river is high and can be very dangerous if you are not paying attention, with river rescues common at these flows. Clarity has been stained at higher flows, with turbidity improving after sediment pushes. Nymphing is a highly productive method, especially with indicator rigs. Standard nymphing involves Rubberlegs and various bead heads. Small flies are often the name of the game, with a strong favoring of nymphs in sizes 16-20. When flows are increasing, trout tend to favor larger food, while stable flows lead to a preference for smaller flies. It is critical to change split shot frequently and match your rig to the water you are fishing, especially with increased flows. Dry/dropper rigs are also an excellent choice and offer plenty of room for exploration. Streamers can be effective, particularly if clouds and afternoon thunder-bumpers move through. Golden Stones are flying around, and some anglers are doing well running dry Golden Stones through the canyon. Gray Drake Spinners are also present, with fish eating them near the boat ramp. Giant stoneflies are diminished, but Golden Stones remain active. In the afternoons, Golden Stones continue to trickle off, providing a fun dry fly option. Evening caddis activity offers some of the best dry fly fishing. PMDs, caddis, and midges are also important to consider for nymph selections. Recommended nymphs include PTs, Rubberlegs, Zebra Midges, Caddis Pupa, Copper John, Hare/Copper, 101 Stone Nymph, Perdigons, and Split Cases. For dry flies, Splitsville Trico is a good choice. Have a supply of Perdigons, Daggers, PTs, and Zebra Midges in sizes #14-20. Rubberlegs in #8-10 are also effective. For indicator nymph rigs, consider Tungsten PTs, R/L Tactical PTs, Split Cases, Hare/Copper, HP Caddis Pupa, Rednecks, red Zebra Midges #14-18, Olive Hot Spots, red Napoleon Jigs, and Duracells.