Fly Fisherman Throwback: A Primer of Stream Entomology­–V: The Snow Fly

Editor's note: Flyfisherman.com will periodically be posting articles written and published before the Internet, from the Fly Fisherman magazine print archives. The wit and wisdom from legendary fly-fishing writers like Ernest Schwiebert, Gary LaFontaine, Lefty Kreh, Robert Traver, Dave Whitlock, Al Caucci & Bob Nastasi, Vince Marinaro, Doug Swisher & Carl Richards, Nick Lyons, and many more deserve a second life. These articles are reprinted here exactly as published in their day and may contain information, philosophies, or language that reveals a different time and age. This should be used for historical purposes only.

This article originally appeared in the December 1972-January 1973 issue of Fly Fisherman magazine. Click here for a PDF of the print version of "A Primer of Stream Entomology-V."

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Part Five of a series of articles designed to familiarize fly fisherman with the practical aspects of stream­ side entomology. The series will cover the favorite fare of trout, smallmouth bass and even bluegill in all of their habitats, slow water and fast, from farm ponds to high mountain lakes. Mr. La Fontaine is both a scientist and fly fisherman who goes where the fish and the hatches are.

The sun sparkled brightly on the water and the edge-ice of the Clark's Fork of the Columbia.

My line landed upstream, with a slight curl brushed into the leader by a puff of wind. The #16 dry fly floated down the flat and I stripped in line. When the rainbow swirled under the fly I pulled out the slack and tipped the hook, and in the shallow water the trout ran and split into the air. I saw for certain that the fish was not a whitefish and I played him gently. I released the 13- inch trout back into the 40° water.

It was a warm day, with the air temperature reaching almost 50°, and it was a day that was part of the long season of the Rocky Mountain fly fisherman. The angling year ends on many streams in Montana on November 30, but other rivers remain open. The win­ter water runs clear, and trout and whitefish are caught on weighted nymphs, and even the dry-fly purist is not snow-bound.

The important insect of mid-winter on Western rivers, the attractor that will bring the fish to the surface, is the little stonefly, Plecoptera capnia. Beginning in late January, emergence begins with the movement of the larvae to the rocks and sticks along the bank. With a last molt, the skin of the larva splits and the adult clambers over the snow to seek a hiding place. On days that are cold the stonefly stays under the rocks. The best angling is on the warm days when the insect flies and glides to the water with a clumsy "splat."

I first heard about the insect called the "snowfly" when I came to Montana, but during the first winter, when the temperature dropped to 30° below zero in a cold snap, I did not think about fishing. Then a warm pocket of air settled on the valley and lingered. I waited at home one day for my wife. Child-bride, sympathetic although not a fly fisherwoman, came home from the university on February 18. Having recognized a hatch in progress, she said, "Guess what?"

I guessed right and I drove up to the north side of the Clark's Fork, on the flat above the horseshoe rapids in Missoula. I fished, and I began to learn that day. the hard way, how to fish the winter hatch. I watched the rain­ bows and whitefish cruise the shallows and nose up for the struggling stone­ flies. None of my standard assortment of patterns came near to matching the snowfly, so I tied on a # 14 Sedge in hopes of approximating its silhouette. I flailed, casting first to one rise and then to another, and even the whitefish would not strike. As the sun backed from the river and the chill drove me off, I went home knowing that I needed some polish.

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As my over-anxiousness about the first subsided, I began to refine both my fly pattern and my technique. On the still, clear water I experimented with the Little Black Stonefly pattern, starting with a fully hackled fly, but finding a clipped fly, with hackle trimmed top and bottom in the manner of E. R. Hewitt's Neversink imitations, generally to be more effective. I used this altered fly in sizes #18 and 16.

Further testing with pattern types (tied upwing to simulate a flying in­ sect, no-hackle, and fur flies were tried, all without improved results) proved a hairwing version of the Little Black Stonefly to be as effective and more durable than the prescribed duck quill dressing. This hairwing fly, with a sparse wing tied from the fine, black hair of a Monga ringtail, became one of my two staple patterns of the Mon­tana snowily season.

I tried also to imitate the insect in movement. The tiny stoneflies run across the surface film, wings fluttering, scattering an imprint of silver points onto the mirror of water. One day, with gusts of wind riffling the water, I tied on a small black bivisible. The fly was tied with natural. high-quality hackles, and it tossed with the wind. A 12-incher sucked in the fly as it danced across currents and I landed the fish. The soggy fly, even with false casting, did not float high, so I changed to the only other bivisible in my box. On the first cast this fly also hooked a fish. Similar experiences on windy days bore out the value of a fresh bivisible, or other type of skating pattern, but if the fly became lower-riding after a few casts or was sunk with a missed strike, it worked less effectively than the Little Black Stonefly. To be deadly the fly had to skate, not drag with a wake, and on calm days or in calm spells of windy days the bivisible was almost completely ignored by the fish.

My technique also evolved, changing to fit the cruising pattern of the fish. I made my approach a gentle one, wading the shallow water upstream, keeping my false casts away from the rises of the fish. I cast repeatedly and carefully to a lie or a current and tried to ignore the scattered rises. Since the fish do not hold a steady position, a cast to a rise is only to a spot where there used to be a fish. The cruising pattern of the trout and whitefish is similar to their method of feeding during many other stonefly hatches, including the salmon fly hatch (Pteronarcys), and on active terrestrials. The fish move to the fallen insect. The insects are not gathered into strict drift lanes and the fish move quickly to capture the insects before they can escape.

Taking twenty minutes on the lawn one day, I roughly mastered the basics of the negative curve cast. Out on the stream I under-powered my right-hand side-arm cast. I pushed the line across the current with a curved loop down­ stream to my right. This put the fly over the risers before the line and leader. When a fish rose in the vicinity of the drifting fly, a twitch on the line made the fly skip and I watched the trout ascend back into view and drift down to meet the artificial. Fooled, it turned with the fly and hooked itself. It thrashed against the snug line until it tired and I landed the 1½-pound rainbow.

There are anglers in the Rockies to whom this winter fishing is an art, and I plague these men with questions about places and times and horde the secrets that they sparingly divulge. Many Montana fishermen prefer catching the mountain whitefish (Prosopium williamsoni) rather than the trout, and, despite what some say, this relative of the trout offers both sporting and delicious eating. The rainbows are usually caught in a ratio of about 1 to 5 with the whitefish. I do hear stories, shady rumors whispered, about five-pound trout that are caught in the winter on the Clark's Fork near the town of Superior and in the Bitterroot near the town of Hamilton, and anything is likely on these big Western rivers.

In and near Missoula there are three major rivers that are locally known for being productive during the snow fly hatch. The Clark's Fork is a fickle river, muddying fast with a rain and subject to high winds, but it on the average produces the largest fish and it is an excellent rainbow fishery. The Bitterroot is the most consistent of the three rivers, and holds a large population of whitefish. The Blackfoot is a beautiful water with deep pools and long slicks, but like the Clark's Fork it produces best for those who know it well.

In Montana the emergence period of the numerous species of the genus Capnia is heavy from late January to mid-March. In any area of the West, local tackle shops, and especially fly shops, will have information about winter fishing. Fishing the snow-fly hatch is a popular past-time of the dedicated fly fisherman.

In the East, now that many states are opening rivers to all-year fishing, anglers can fish over the single Eastern species of the genus, Capnia vernalis. This insect has been recorded to emerge from late February through late April.

Many of the angling problems faced during the snow-fly season are identical to the challenges of low-water, mid­ summer angling. I look forward to the sporadic winter days when escape from the angling dreams to the reality of a well-placed cast or a jumping fish is possible. It is not an easy kind of fishing, but the best moments are the bright, beautiful days of the Rocky Mountain pre-spring, and the anomaly of catching winter fish on a dry fly is a unique thrill.

Snow Fly Imitations

Black Bivisible

• Body: Black thread
• Hackle: Black palmer over length of hook, sparse white front
• Tail: Black hackle fibers

Little Black Stonefly (Charles Wetzel)*

• Body: Badger hackle quill, stripped Hackle: very dark, blackish-grey dun
• Wings: Black duck tied flat over body and lacquered Tail: black hackle fibers
• Silk: Black

If a fly is to be trimmed top and bottom, I use the following hackl1ng procedure to prevent an unbalanced look in the clipped fibers. This method requires a few extra moments but the resulting product appeals more to the fly tier's sense of aesthetics.

*Pattern dressing listed in Matching the Hatch by Ernest G. Schwiebert, Jr.

1. The butts of two hackles are tied in (dull side of hackles to be facing forward) and secured with a half hitch.
2. The hook shank where the hackles will be wound is dabbed with head cement.
3. The first hackle is wound towards the tier (contrary to normal procedure) and wrapped securely and half hitched. The cement is allowed to sit for a few moments to dry.
4. The second hackle is wound away from the tier, worked evenly through the first hackle.
5. Whip finish. Clip notches into hackle top and bottom.

Little Black Stonefly

• Variation 1: The wing of the fly is tied down, and sparse, with the black hair from a Monga ringtail, or with any fine, straight black hair.
• Variation 2: The body of the fly is thinly dubbed with black rabbit fur and ribbed with tan thread.