5 Best Flies for Trout in Utah

The San Juan Worm is the anchor pattern on both the Green River at Flaming Gorge and the Provo below Deer Creek - two of Utah's most productive tailwaters. Aquatic annelid worms are an important food source in the rich, silty environments created below dams, and Utah's tailwater trout have learned to seek them out year-round. Red and pink in #12 are the standard starting colors.

On the Green River's A section, the most productive near-dam stretch, the San Juan Worm fished as the point fly in a two-nymph rig accounts for an enormous percentage of the fish caught throughout the season. It doesn't look like much, but it produces with remarkable consistency.

Utah's tailwaters are fundamentally midge fisheries. The cold, stable water below Flaming Gorge and Deer Creek Dam creates perfect chironomid habitat, and the trout's diet reflects it - midges in all life stages are available and consumed throughout the year. The Zebra Midge, Disco Midge, and Mercury Midge are the three patterns that cover the most situations.

Size is critical - Utah tailwater fish see enormous fishing pressure and will refuse midges that are even one size too large. Carry sizes #20 through #26, and don't hesitate to drop to the smallest sizes on heavily pressured sections. Use fluorocarbon tippet in 6X or 7X for the most natural presentation.

Spring and fall BWO hatches on the Green and Provo rivers provide Utah's best dry-fly opportunities. On the Green River, overcast autumn days from September through November trigger dense BWO emergences that bring large rainbows and browns to the surface - the best surface fishing of the year for anglers used to nymphing Utah's tailwaters. A #20 Parachute BWO on 6X tippet is the standard approach.

Spring BWO hatches on the Provo in March and April can also be excellent, particularly in the canyon section where fish are accessible and the hatches are visible and predictable. Watch for overcast, cooler afternoons - these conditions consistently produce the best emergences.

The Pheasant Tail Nymph is the versatile workhorse across all Utah trout rivers. On the Green River, it works well as a dropper behind a San Juan Worm, covering the mayfly-nymphing behavior that Green River trout engage in when they're not focused on worms. On the Logan and Weber rivers' more diverse insect communities, the PT Nymph is an essential all-around nymph.

During BWO hatches on the Green and Provo, a #18–20 PT Nymph fished in the film is often more effective than a dry fly in the early stages of the emergence - Utah's tailwater fish key on emerging nymphs before switching to fully hatched duns on the surface.

Utah's freestone rivers - the Logan in Cache Valley and the Weber in the Wasatch Back - have good summer caddis hatches that call for the Elk Hair Caddis. These rivers offer a different experience from the tailwaters: freestone pocket water, more varied trout behavior, and evening caddis hatches that produce aggressive surface rises from smaller but eager wild trout.

On the Logan River in particular, summer caddis hatches from late June through August produce excellent dry-fly fishing in the scenic Logan Canyon. A tan Elk Hair Caddis in #14–16 is the searching fly that covers this water from opening to close.