Fly Fishing the Missouri River
Just over the continental divide from Missoula lies the Missouri River. We run guide trips on the Missouri year round but tend to focus more on this river when streamflows closer to Missoula are fluctuting from snow melt in May and June.
Sometimes the Missouri below Holter Dam can fish like a trout pond, with anglers river-wide catching more 18-20” rainbows on nymphs than they ever dreamed of. Other times—say, when the size 24 Psuedocleon mayflies blanket the river and fish sip in six inches of water—“The Mighty Mo” can strike anglers as the most refined, technical fly fishing water in the world.
With roughly 6000 trout per mile and a biomass of bug life that rivals any fishery in the world, the Missouri is inarguably one of the West’s top fisheries. In Missoula, we consider it our “Ace in the Hole” because, as a tailwater with dam-controlled releases, it often fishes very well when the Westside’s river are unfishable with runoff (early May through mid-June). The Mo is a very adaptive, resilient fishery, too—for instance, we’ve logged outstanding days here at both 2000 and 20,000 CFS.
Although many anglers concentrate on the very productive first ten miles of water below the Dam (and certainly catch plenty of fish) they miss out on some of the river’s true character. The upper river from the Dam to Mid-Cannon, fishes like a gigantic spring creek, with fish concentrated near weed beds and drop offs.
Below mid-Cannon, the river enters a canyon with large red rock walls and boulder gardens holding huge brown trout and hard-fighting rainbows. It’s not uncommon to see bighorn sheep scaling these steep walls, or eagles soaring over the clear water for a better look below.
Just below Prewett Creek and Sheep Creek Rapids, the river leaves the canyon and winds through grasslands on its way past Cascade. The fish of the lower river tend to behave more like freestone fish, but they still gorge on prolific caddis and mayfly hatches, as well as terrestrials throughout the summer. Some of the biggest brown trout of the year are caught down here, and the coveted two-footer is a reasonable goal.
Fly Fishing the Missouri River by Season
This is when we move to the Missouri. Literally, we move there.
While the Missouri fishes well all year long, we typically start heading over Rogers Pass in late-April, when our early season Stonefly hatch on the Clark Fork and Bitterroot has begun to wane. This time of year usually finds the Missouri’s post-spawn rainbow trout piling back into the shallow riffles to bulk up after mating. The big ‘bows are hungry, and easy pickings on scud and sowbug patterns. This angling pattern is dependable for tackle-busting rainbows throughout early spring, and the big browns, fattened up from eating rainbow eggs, will often fall prey to large slowly stripped streamers. By early May we’ve usually begun to see our first hatches of Blue Wings, and March Browns. It is then we start “head-hunting,” looking for pods of risers in the back-eddies and singles (usually the brutes) along the grassy banks. Mother’s Day Caddis will come into play before too long, and the PMD hatch usually starts here before anywhere else in the state.
There is generally a high-water period on the Mo before the river drops into mid-summer shape, but this bump in flows often marks the start of “worming season,” when some of the biggest fish in the river get football-fat on aquatic worms knocked out of dirt banks by rising flows. Fishing a short-leash double worm along the undercuts or a long, long leash near the mid-river weeds can be a blast.
Summer on the Missouri River
In the average year, early June means tan caddis and PMDS and dependable dry fly fishing on the Missouri. This fun lasts for a good month before the bugs get smaller (Tricos) and the fish get pickier. Hoppers, ants, beetles, standard attractors, and even damselflies can produce throughout the summer as well.
Fall Fly Fishing on the Missouri River
As late summer gives way to early fall and first frosts, the Mo will see some weed die-off that makes for tough fishing everywhere but near the Dam. Tiny Psuedos dominate the water column making for the most technical fishing an angler will ever encounter. A dragging fly here will not only fail to catch fish, it will spook fish, and their friends. Come ready with a reach-cast, or don’t come at all.
Thankfully, this difficult portion of the season soon gives way to the gravy train of Baetis hatches and amazing wooly bugger fishing. Late fall on the Mo means nasty weather and even nastier trout feeding in shallow water on dense hatches. A short-leash nymph rig this time of year can rock em’ as well.