BEAR TRAP CANYON — In the turbulent waters beneath the Madison Dam the form of a single fly fisherman appears. An overcast sky cuts the glare from the water, and the rocks and pools and eddies reveal the topography of the river below.

No rising fish are breaking the surface of the water, but it's early. Perhaps the midge pupae and mayfly nymphs are stirring beneath the surface. A shift in the wind turns the light rain white, and suddenly the scene is cloaked in snow.

The flurries last just moments before the rain returns. The veil of snow lifts from the river, revealing the angler with an arced rod. A trout breaches the surface of the river and returns with a splash.

It's spring in Montana: tailwater time.

Here's a breakdown of the region's five best tailwater fisheries:

Hauser Dam

Located a short drive from the state capital, Hauser Dam, along with the Missouri River below, is one of Helena's premiere trout fisheries. Runs of spawning rainbow trout from Holter Lake offer anglers the chance to catch a legitimate trophy.

“It is a pretty mixed crowd of angling techniques,” said Chris Strainer of CrossCurrents Fly Shop in Helena. “There are lots of guys fishing with spinners and bait, as well as fly-fishing. It is a social event. You are there with a lot of other people.”

Strainer said many fly fishers use hot pink or hot orange fire beads ahead of a scud or sowbug pattern. Strainer said the fish take the bead as an egg but are hooked by the scud or sowbug.

Traditional nymph fishing isn't as effective as on other waters, Strainer said, but trout may take streamers.

“A few years ago our fisheries biologist, Steve Dalby, made the change on the strain of rainbow they stock in Holter Lake from an Alree strain to an Eagle Lake strain,” Strainer said. “The Eagle Lake strain lives about a year longer, they behave more like a wild rainbow and they may have the ability to reproduce naturally.”

Strainer said anglers fishing below Hauser Dam should be cautious not to wade over spawning areas and to exercise discretion when fishing to spawning trout.

Holter Dam

After the Missouri River passes through the Gates of the Mountains Wilderness, it emerges at Holter Lake. The river below Holter Dam, downstream to the town of Craig, provides excellent spring fishing opportunities.

“Midges are real thick right now,” Strainer said. “Blue-winged olives (baetis mayflies) will show up some time in April once we get into 40-degree temperatures. Dry fly fishing now with midges is weather dependent. If the wind kicks up, they are done.”

Strainer said anglers fishing below Holter Dam will have success with the same scud and sowbug patterns that are effective beneath Hauser Dam. Griffith Gnats, Parachute Adams and Buzz Balls will take fish on the surface during midge hatches.

“One of the nice things about fly-fishing right now, your box can be pretty sparse,” Strainer said. “One dry fly, one streamer and couple nymphs will get it done.”

Strainer said anglers focus on tailwaters during the spring because of their consistency, and Holter Dam offers some of the most consistent fishing around.

“Holter stays pretty consistent with temperature and runoff this time of year,” Strainer said. “And the fish are just big. People come in here pie-eyed after fishing either stretch, Hauser or Holter.”

Ruby Dam

The Ruby River rises in the Snowcrest Mountains south of Virginia City. The upper river flows through mainly private property before reaching Ruby River Reservoir on the east side of the Ruby Range.

The Ruby is a medium-size, easily waded river with healthy stocks of brown trout and the occasional rainbow.

Mike Lum, manager at Madison River Fishing Company in Ennis, said small wooly buggers and nymphs like Pheasant Tails, Hare's Ears and Copper Johns and good bets during the spring.

Lum said anglers headed to the Ruby should keep a close eye on stream flows.

“It can jump at any time and jump pretty substantially,” Lum said. “A spike in flows, when they come up it can put (the fish) off and create some dirty water.”

Access below the dam is currently limited due to construction.

“We lease (the Ruby Dam fishing access site) from DNRC,” said Ray Heagney, Montana Fish, Wildlife & Parks Region 3 fishing access site manager. “They are working on the spillway right now and there is heavy equipment in there operating. The work is scheduled to be complete by the first of July.”

Anglers interested in fishing the Ruby River below Ruby Dam should access the river at the Vigilante fishing access site several miles downstream from the dam, or the Alder Bridge fishing access site in Alder.

Hebgen Dam

The Madison River leaves Yellowstone National Park and flows briefly before dumping into Hebgen Lake. Highway 287 follows the north shore of Hebgen Lake west to Hebgen Dam.

Hebgen Dam feeds the upper Madison River. The river flows just over a mile beneath Hebgen Dam before entering Earthquake Lake, formed by a landslide caused by a magnitude 7.5 trembler on Aug. 17, 1959.

Cam Coffin, manager of Blue Ribbon Flies in West Yellowstone, said good numbers of spawning rainbow trout move from Earthquake Lake into the water below Hebgen Dam in the spring.

“Historically you do get a big run of fish that spawn there,” Coffin said Monday. “There are fish they have tagged at Lyons Bridge that move up there to spawn.”

Coffin said nymph fishing produces better results below Hebgen Dam until the dry fly bite starts with the arrive of baetis mayflies in April. San Juan worms and rubber leg nymph patterns are popular.

“Typically in April and even in May, if a guy is patient and looking around you can finds some heads up for sure,” Coffin said.

Coffin said flows below Hebgen Dam have risen in the last week. He said elevated discharge from the dam doesn't affect the fishing as much as on other tailwaters and that the bump in flows can spur a run of fish up from Earthquake Lake.

Madison Dam

Just east of McAllister, Madison Dam forms Ennis Lake. The Madison River spills over this top-water dam before coursing some 9 miles through Bear Trap Canyon. The mile-long section of turbulent river below Madison Dam is a favorite with spring anglers.

“(The Madison) has been really, really good, both (below Madison Dam) and down below in the canyon,” Lum said. “We've seen dries inconsistently. There is a great baetis hatch down there in that flat water on the lower river once we see 40s and 50s and no wind, which can be a tough combination. Once it gets going though, it is a really big deal around here.”

Lum said Yuck Bugs and crayfish patterns are working well on the lower Madison. He said anglers will also find success fishing egg patterns and Pheasant Tail, Hare's Ear and Copper John nymphs.

Ben Pierce can be reached at bpierce@dailychronicle.com and 582-2625.