SOMEWHERE OVER IDAHO – Between steep canyon walls, the Selway River wound below us among boulders the size of pickup trucks. This was a few days ago, and Paul Ehlen banked the helicopter over the tops of ponderosa pines and Douglas firs so thick the craggy landscape seemed impenetrable. Losing altitude now and still more, Paul angled the Eurocopter A/S 350 steeply within the river canyon, then raced the machine downstream about a mile before arresting its forward speed, tilting it slightly tailward and settling us gently onto a bed of dry grass and small rocks. Not far away, the Selway, one of the world's most beautiful rivers, rumbled and spilled, bisecting the Lower 48's third-largest wilderness area.

We had come to fish the Selway's westslope cutthroat trout in water so clear you can see a fish rise to a fly from 4 feet down. On this day, two small bush planes were parked helter-skelter alongside our remote landing strip, perhaps having dared the mountain updrafts and sudden cloudbursts on a lark, or perhaps to camp or to start or end a rafting trip. In any case, the strip undulated in the manner of a kiddie roller coaster, challenging pilots on approach, and is one of more than a dozen such makeshift fields carved out of Idaho's backcountry, kept there for fly-ins such as ours, but mostly for forest-fire crews and rescue teams.

With six of us on board, we had come in heavy. Also we toted our fishing gear, lunches, emergency equipment and the odd really big revolver. This last, we imagined, might serve no good purpose, except perhaps to discourage the occasional rattlesnake. Also its heft feels comfortable in hand, and anyway we were west of the Mississippi, suggesting, somehow, the sidearm's appropriateness, if not necessity.

"It's about a 2-mile hike back upriver,'' Paul said as we assembled fly rods in the chopper's long shadow.

We were a motley crew.

Paul is a longtime friend from Bloomington and hobbyist pilot who can fly just about anything with wings — or, as in this case, with blades and a rotor.

Also along was Ken Weinheimer, a helicopter pilot who for years flew rescues, among other work, in these same mountains, before which he ferried L.A.'s beautiful people to fancy lunches and beach galas, all the while dodging other helicopters on similar vectors while hovering high above the clogged 405 or Hollywood Split.

"It was good to get out of there,'' Ken said.

In our group as well was Robert Gary, an expert angler, Montana fly fishing guide and owner of Latitudes Outfitting Co. in Hamilton, Mont. And we had picked up my son, Trevor, a student in Missoula and also a Montana fly fishing guide whose boss, Robert, had given him the day off to fish with his old man.

Finally, and as evidence of just how accepting the five of us were of foreign cultures, we allowed a California guy, Doug Gloff, to tag along — but only because he's originally a Midwesterner (Indiana) who is happiest while residing at his Montana river place.

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Horses are the other way to reach this portion of the wilderness, and the six of us followed a tired path beaten over many years by tired hooves, this while the morning revealed itself in bursts of optimism.

As we hiked, the very wild Selway twisted below us in varying degrees of declension, and from the trail we spotted deep pools and other areas likely to hold trout. Littering the way forward were pine deadfalls and the craggy flotsam of ancient geologic collisions. Finally we dropped down to the river in ones and twos, tiptoeing from rock to rock with fly rods in hand.

Streamside, Trevor said, "Try this,'' and handed me a Chernobyl Ant, also known as a foamy thing with legs.

I tied the fly on.

Then, throwing a 5-weight with 4X tippet, I sent a loop of line airborne, watching as the fake bug settled onto the rushing river, and watching also as it gathered itself quickly amid foam lines of separating currents.

Then it was carried downstream, its appearance to trout, I hoped, that of fast food offered free.

There.

This was my first Selway cutthroat, a small but feisty specimen whose blood-colored slash beneath its gills revealed its delicate lineage.

Calf-deep in the river, with my arched fly rod pulsing against the fish and the fast water, I felt the Selway envelop my legs in bubbles, just as it did its innumerable rocks — some small, many large, a few massive.

The river, I thought, appeared so clean and devoid of obvious food sources that it should be incapable of supporting fish, much less populations large enough to supply anglers' routine claims of 50-trout days.

Yet mayflies and stoneflies are found here, also caddisflies. And spotting one of these, or its reasonable facsimile — think Chernobyl Ant — can incite a Selway cutthroat to sling from its shadowy haunts like an arrow from a bow.

My fish measured about 10 inches, and when I released it, the trout disappeared instantly, unharmed, in part because of the barbless flies we cast.

Downstream and upstream, meanwhile, amid the din of the swift river, muffled whoops and hollers regularly arose to signal trout had been caught there as well.

Perhaps these fish would be bigger than mine — our largest of the day measured about 15 inches. Or perhaps they would be rainbows, or even bull trout, both of which also swim in these waters.

But fish size and species didn't seem so much the issue on this day.

Downriver, where the Selway joins the Lochsa River to become the Middle Fork of the Clearwater, which ties into the South Fork to form the main Clearwater, Lewis and Clark climbed into dugout canoes in October 1805 en route to the Pacific Ocean.

Whether this rough country is any less wild now than it was then might be a toss-up. If it is, perhaps not by much. Witness the large elk herd that roams here, also bighorn sheep and now, again, wolves.

Early afternoon came and we gathered on the horse path to eat sandwiches. By then, the higher sun had chased shadows from the river that earlier had hung like curtains from the canyon walls.

The fishing had been good and would continue good, and the freshness of it all seemed not to wear off.

But finally we worked our way back to the airfield.

Ken would fly us out, and after we had stowed our gear and clambered aboard the helicopter, he red-lined its motor in the now-lighter afternoon air.

Soon airborne, but barely, he turned us downwind, toward the tall ponderosas and firs at the end of the strip, still gaining no altitude.

Then he banked the machine steeply back into the wind, dipping its nose smartly and springing us quickly skyward, as if from a launching pad.

Smaller and smaller below us, the Selway narrowed until it was only a ribbon of blue dividing tall mountains.

danderson@startribune.com