TRAIL — For a short window of time Tuesday, Chris Gross found himself in trout-bum heaven.

TRAIL — For a short window of time Tuesday, Chris Gross found himself in trout-bum heaven.

Cast after cast, his fat, imitation salmonfly would belly-flop onto the surface of the Rogue River's famed "Holy Water" impoundment, acting like a dinner bell to the rainbow trout below.

Thinking this 2-inch-long fly was the real McCoy, the rainbows darted after it like it was another of the free, double-cheeseburger-like salmonflies they'd been gorging on all morning. But this one had something sharper than cheese in it, and the tug-o-war that fly-fishers live for was on.

"For a bit, it was fantastic," Gross says. "I probably raised 30 fish and landed 10 or 11 of them, and it was all in 45 minutes. Then it was over."

This is the magic of the salmonfly hatch, a combination of massive flights of macro-bugs and bingeing rainbows that turn steelheaders into trout bums for one magical month on the upper Rogue.

Salmonflies now plying the skies over the far upper Rogue are the biggest of the water-born insects here, and their annual hatch triggers a feeding frenzy in the Rogue basin's trout waters that is unmatched by any other hatch.

It's all about casting huge, orange-bodied, dry flies among the rafts of real flies up to 21/2; inches long that are floating on the surface. They're the largest of the stoneflies revered by fly-fishers in Western states and go by the nickname salmonfly because they hatch in the midst of the spring chinook return in rivers such as the Rogue.

They hatch after the winter steelhead run but before the Rogue's summer steelhead show up in good numbers, mainly when water temperatures hit 55 degrees.

Their timing makes them a perfect bridge for steelheaders segueing from one addiction to another. They're also a hatch of choice for the myopic trout-lovers who relish a change from casting tiny dry flies or nymphs.

Cast them for resident rainbows throughout the Applegate River. Smallmouth bass eat them from the surface of Lost Creek Lake just upstream of the dam. A few resident trout as far up as Union Creek will mouth them, too.

Eagle Point fly-fishing guide Dave Roberts casts them exclusively from his driftboat this month on the upper Rogue near Eagle Point for native cutthroat trout, rainbows and even early-run summer steelhead — all of which can't pass up what appears to be a free meal.

"I've had seven (summer) steelhead come to hand this past week, plus big cutthroat," Roberts says. "The trick is locating the fish and dodging the salmon fishermen."

And nowhere is that better than the "Holy Water" impoundment, a .8-mile stretch between the base of Lost Creek Dam and Cole Rivers Hatchery. It's Oregon's only river stretch where hatchery trout are stocked strictly for catch-and-release angling with barbless flies and only traditional fly gear.

It also is the salmonfly's Mecca.

Bugs that hatch in the Rogue fly upstream until they hit the dam's edifice, and the salmonflies hover the thickest at the dam's water outlet.

Fly patterns start with the Rogue Foam Stone, a size No. 4 fly that emphasizes the salmonfly's orange body and pterodactyl-like wings that give the bug its scientific name, Pteronarcys californica. The smaller and more sparse Clark's Stonefly is another Rogue Basin staple, as is the "Stimulator."

The water's holy reputation drew Tim McDonald from Portland on Tuesday, who promptly battled and landed a 14-inch rainbow on his first visit.

"I keep hearing there are monsters in there," McDonald says. "We'll see."

But even in this buggy nirvana Tuesday, there was plenty of evidence why this endeavor is called fishing and not catching.

Mid-way through the season's hatch, the trout are so gorged on salmonflies that they have trouble fitting another in. And with so many live bugs on the water at any given time, the rainbows can get downright picky.

Gross knew the drill all too well.

For the past 20 years, the Corvallis man has spent a week in mid-June on the impoundment with his arsenal of salmonflies, with the all-too-predictable mixed results.

"It varies year to year, day to day, hour to hour," Gross says.

In between those magical 45-minute fishing fits like he had Tuesday, Gross can't help but continue casting while eyeing the ospreys, bald eagles and other fauna that call the impoundment home.

"If I'm not catching anything, I look around and say to myself, 'you've got nothing to complain about,' " Gross says. "And who would listen to you if you tried?"

Reach reporter Mark Freeman at 541-776-4470, or email Follow him on Twitter at