I know this because a week or so ago, I tromped through a good foot and a half of powder along the river, up past the first set of falls, to a series of pools that call to me when the regular stream season closes at the end of November. Thanks to Utah Power and Light — the corporation that allows access to the area — and the Department of Fish and Game, the Bear River  through Black Canyon remains open all year, providing a winter retreat for stream fishers flushed from the banks of the Henry’s Fork, the South Fork and the upper Portneuf.

But it’s no picnic. The Gem Valley gets its share of winter — iced-up guides, frozen fly reels and 10 numb toes will attest to that after a December day on the water. Nevertheless, winter’s the prime time to visit Black Canyon, in my opinion. During the summer months, I prefer to venture into the backcountry in search of wild trout and some solitude. During the snowy months, solitude aplenty can be found between the walls of Black Canyon, and the rainbows can be coaxed to a fly with some regularity.

I visited Black Canyon last week between storms, breaking a squeaky trail through the unbroken crust of snow in the process. Enjoying what’s become a rare sunny day, my old dog Spooner and I had the river to ourselves — a rarity for flyfishers who visit the same stretch of water during warmer months.

The sunshine, while welcomed by the soul, kept the river’s midges from hatching out. Generally, during a cloudy winter day, thousands of tiny black bugs will plop from the surface of the Bear River, enticing the resident rainbows to rise in search of a meal. It’s a wonderful stretch of water to visit on a cloudy day armed with a fly box full of Griffith’s Gnats. On a clear day, though, a fly fisherman must take a hint from Jerry Rice and go deep.

But sinking a fly in the crystal waters of Black Canyon is a risky proposition. Anyone visiting the Bear can tell just by looking that the river is a moss-lined quagmire, even during the cold winter months. On nearly every cast, a weighted fly will pick up a tail of moss.

Small sacrifice, however, for if an angler is lucky enough, as I was last week, he’ll stumble on some deep pools holding hungry trout willing to strike a dead-drifted nymph imitation.

I use an olive green attractor tied on a size 14 scud hook and equipped with a heavy tungsten bead head. To give the fly a little swimming action, I tie in a short olive maribou tail and a couple strands of flash material. The body is dubbed and reinforced with thin brass wire. The thorax consists of peacock herl wrapped right behind the shiny tungsten bead. It’s easy to tie and very effective.

While the heavy fly works in all kinds of colors, during the winter months the olive dubbing or a Canadian brown mohair yarn version seem to be most attractive to Black Canyon’s rainbows. Don’t bother with a sink-tip line — a full floating line is adequate. With the heavy fly at the end of the leader, the fly line acts as a poor man’s strike indicator.

Casting directly upstream into one pool no larger than the average coffee table, I was able to reel in five rainbows — I had a strike on nearly every cast into the hole. The largest fish was about 15 inches and the smallest measured about 10 inches. I cast the heavy fly to the head of the pool, and left just enough tension on the line during the downstream drift to recognize a subtle strike — the fish weren’t as aggressive as they might have been on a warmer day.

Chris Hunt is the Journal’s city editor.