Montana's Smith River is one of the West's legendary fly fishing trips. The river winds through 60 miles of wilderness between public access points and is strictly regulated by Montana Fish Wildlife and Parks to ensure the pristine beauty of the canyon is not overrun. The river corridor is comprised of towering limestone cliffs and heavily timbered forests broken only by a few small clusters of cabins on private land. Because of the strict permit system, fishing pressure on the Smith is much lighter than on other major Montana rivers. Both Rainbows and Browns are present in good numbers, and fish over 20" are taken on virtually every trip. Floating and fishing on the Smith generally takes place in May, June, early July and September. Late July and August are generally too low for floating. There is typically enough water to float again in the fall after irrigation season ends and fall rains help to raise the river. The exact conditions during your Smith trip are very hard to predict because launch dates are set far in advance and runoff is different every year depending on snowpack levels and weather.
Seasons for Fly Fishing the Smith River
During the pre-runoff period, which generally means April until sometime in mid-May, both surface and sub-surface fishing can be very productive. Spring sees hatches of Caddis and Skwala Stonefly's that bring trout to the surface in the afternoons. During the mornings and non-hatch periods, nymphing with Rubber-legged Stoneflys and Prince Nymphs is very productive. Streamer fishing can be dynamite in the spring as well. The Smith has a large population of Brown Trout, and the larger, predatory Browns can be suckers for a big streamer. Oftentimes the largest fish of the trip falls victim to a streamer. The Salmonfly hatch typically begins on the Smith during the middle of May and lasts for several weeks. The big wildcard here are water conditions, as this is often right at the beginning of runoff. If the water conditions are favorable, the Salmonfly hatch is a sight to behold. There are not many opportunities to have fish rise to a size 2 or size 4 dry fly, and this is one of them. The nymphing should be stellar at this time as well with big, black stonefly imitations.
The Smith will typically come out of runoff around the second week of June, but this is highly variable and different every year. There is a chance that the Salmonflies may still be hatching, but more than likely the Golden Stones will be the main course for the trout in June. These bugs are slightly smaller but still draw large fish to the surface. The streamer and nymph fishing will be lights out as the river begins to drop and clear. The falling water puts the fish on the feed and this is a great time to swing for the fences with a streamer. Productive nymph patterns will continue to be stonefly and caddis imitations. As the summer moves along, the giant stonefly hatches subside and are replaced by smaller varieties of stones and caddis. This is the time to start fishing your smaller attractor patterns like Chubby's, PMX's, Turk's Tarantula's and the like. These patterns can be mistaken for any number of insects and terrestrials so they cover all your bases. By the time July rolls around there will be little need to fish subsurface, except for perhaps first thing in the morning.
During the fall float season the water will be much lower and clearer than it was during the spring and early summer. This necessitates smaller flies and lighter tippets. In September, hopper fishing will still be good on warm afternoons and Blue Winged Olives will hatch on cloudy days. Small attractor patterns will pick up fish as well, as will Mayfly types like Parachute Adam's and Purple Haze's. Nymph fishing will continue to be good, and will be a good bet before lunch and on colder days. During the fall, small stonefly patterns and Pheasant Tail's are good choices. Streamer fishing will pick up again in the fall as the Brown Trout start to feed aggressively in preparation for the spawn. Streamer fishing will be best on cloudy days but it should produce at least a handful of fish on sunny days as well.