The Shortest Season
Fall on the Henry's Fork
by: Mike Lawson
The elk were still bugling when I parked my mountain bike next to the hitching post on the bend of the river. I could see a big bull through the mist on the river. He was pacing back and forth between his cows and the challenger. As they worked through the meadow toward the timber I turned my attention back to the river.
It had been a cold night and there was still a hint of frost in the shadows. There were no trout rising, no insects on the water but I had the entire river to myself. Last June there had been thirty or forty anglers on this stretch. I casually strung my rod and knotted a size 18 No-Hackle to the fragile 6X tippet. I expected to see plenty of tiny blue winged olive mayflies as well as some larger mahogany duns once the sun warmed things up a bit.
It took a while for the trout to start rising. I watched until I saw a good fish start rising in a dependable feeding pattern and waded into position. The pattern was right but the fish didn't take until the presentation was perfect. The trout was large and powerful, having utilized a full summer of rich insect hatches to grow fat and strong. He finally pulled off in the weeds after a couple of jumps and a long, powerful run.
The river's surface was soon filled with feeding trout. Another angler had waded in about one hundred yards downstream but there were enough trout between us to last the rest of the day. I heard the distant clap of a rifle shot, a reminder of the ongoing elk season and why I had the river almost to myself. Two more shots rang out and then it was silent again, with only the sounds of the river and the geese calling in the distance. On Bishop Mountain, where the shots came from, the forest was crowded with orange clad hunters. A few of them would be lucky but most wouldn't. I sometimes spend a morning with them, hoping to fill the freezer, but when I'm hunting, I always think of the river and the solitude it offers. It isn't long before I'm back with the trout.
After Labor Day the masses thin out. It's more than hunting that takes them away. School starts which eliminates a lot of distant anglers who have families. The weather also plays a part. There is always a long line of Winnebagos and other campers, heading south after the first snow that almost always comes in September. Little do they know that the sun shines most of time in September and October. Nothing terrifies a Californian more than a howling cold wind and a few inches of snow.
I have read that autumn is the time to fish large nymphs and streamers. The big trout go on the feed stocking up for the oncoming winter. I have caught some large trout using these methods. Fall is spawning time for brook trout and browns. They move up out of deep water and are much more accessible and aggressive. What I haven't read is how good the dry fly fishing can be. Several species of mayflies wait until September to emerge. Blue winged olives are small but extremely prolific. The surface of the water often gets carpeted with them. Mahogany duns are larger and the trout love them. Some of my finest dry fly fishing has occurred during mid September to late October on the Henry's Fork, Teton, Firehole and South Blue winged olives include the most widely distributed family of mayflies called Baetis. They seem to love cold nasty weather and some of the most prolific hatches occur when the weather is blustery. Most mayflies need an entire year to develop from nymph to winged adult but many Baetis species need only a few months to reach maturity. They are the only mayfly specie on some cold tailwater rivers where the maximum water temperature never reaches 60¡F. They usually start emerging during mid morning in September but later in the year, as the nights get colder, they hatch better in the afternoon.
I like to use a size 20 No-Hackle with a grey olive body and grey wings to imitate the Baetis. Parachutes and Sparkle Duns in the same color scheme work well to imitate the tiny duns. When the trout get real selective you may need to use emergers or floating nymphs.
These mayflies are so prolific that they can literally cover the entire surface. When this occurs you are often wasting your time trying to "match the hatch". What you have to consider is that if every square foot of surface area is covered with 50 tiny mayflies and you match the hatch perfectly, you've simply increased the surface area to 51 mayflies per square foot. Those aren't very good odds! The advantage in this situation is to offer the trout something that is different enough to get his attention. When trout are heavily feeding on the surface, they work with a deliberate rising rhythm, gulping at regular intervals. Wait until you've determined the trout's feeding rhythm and then try a small terrestrial like an ant or beetle, or an attractor fly like a Royal Wulff, Goofus, or Parachute Adams. Make sure to keep the fly in size 16 or smaller because trout are more selective to size than anything else. You need to remember to be patient. It may take a lot of perfect casts before the fish takes the fly. All you have to do is notice that for every mayfly the trout takes, he lets dozens of naturals float over him without attention.
Most of our local waters also have good hatches of mahogany duns. These are larger mayflies that belong to a family called Paraleptophlebia. They have a dark reddish brown body and dark grey wings. My favorite patterns for the mahogany dun include the No-Hackle, Thorax and Sparkle Dun with the appropriate body and wing color in size 16 or 18. The mahogany duns usually start to emerge earlier in the day than the Baetis but their imitations work well even after the hatch is over and the trout are feeding on the smaller mayflies. You can expect to see mahogany duns on the HenryÕs Fork and the South Fork from early September until mid October most years.
Most of the rivers and lakes in the Upper Snake River Basin offer excellent fishing opportunities during the late season. To try to write about all of these waters would fill a good sized book. My biggest problem is autumn is so short and there are too many places to fish and hunt. I've had to learn to narrow my choices down to a few special places and spend my time there before this special time of the year is gone and winter is here. The Henry's Fork fishes well from the Ashton Dam to St. Anthony late in the season. Some of this water is open year round and produces exceptional fishing on mild winter afternoons. I love to walk from my home in St Anthony to fish dry flies on the river above town. Last September after school, my son, Chris, caught a big brown just upstream from the city park.
There are big trout below the Ashton Dam. Most of them are rainbows but there are also browns. The browns probably filtered down through the Ashton Reservoir. The Henry's Fork has a good brown trout population from Lower Mesa Falls to the Ashton Reservoir. They came from a stocking of fingerlings in the early 80Õs through a cooperative project with the Upper Snake River Chapter of Trout Unlimited and the Idaho Department of Fish & Game.
The tailwater below the Ashton Dam to St. Anthony is some of the finest and varied dry fly water in the world. The population of fish is incredible. Wild trout management with a two trout slot limit has resulted in an increase in average size over the past several years. The water is rich and fertile with exceptional insect hatches.
The trout in this stretch are not usually as selective as their cousins in the Harriman State Park. A size 18 Parachute Adams is usually all you need even though the water is covered with tiny blue winged olives. The larger trout fight hard and you need plenty of backing behind your flyline to allow for long runs. Nymphs also work well but are not as much fun to fish as dry flies. One of my favorite methods is to attach a size 16 Pheasant Tail Nymph behind the dry fly as a dropper. I tie on the dry fly with a clinch knot and tie another section of tippet to the bend of the dry fly. I tie the nymph to the dangling tippet about 18Ó below the dry fly. This method gives me two chances. The trout may take the dry fly but the dry fly acts as an indicator if he takes the nymph.
Fall River is another great spot for late season dry fly fishing. Like most freestone streams, it has torrential runoff in June but is reduced to a fraction of its water volume by late summer. Fall River's rainbows are fat and healthy. They don't average as large as the faster growing Henry's Fork trout but they are wild and beautiful. They take hoppers and other terrestrials as well as bright attractor dry flies.
All of our rivers are beautiful after the frost starts to turn the leaves golden but I don't know of a more picturesque place than Fall River. The rich blends of color from Cottonwood and Aspen trees mixed with fir, junipers and pine contrast with the tumbling water. The trout are eager and easy to catch. When the water is low the holding water is well defined. Most of the trout are small but the deeper water can hold some lunkers. Access is challenging with most of the lower ten miles crossing private land. Most landowners accommodate those who ask permission. There are plenty of public access points at the bridges. There are miles of good water flowing through national forest land upstream to the Yellowstone Park boundary. The fishing is also good from there up above Cave Falls. You need to pick up a Yellowstone Park fishing permit if you fish above the park boundary. You can get that at the Bechler Ranger Station. (The Bechler River is also a great spot if you don't mind hiking 4 or 5 miles).
Another of my favorite fishing spots late in the year is Henry's Lake. I don't know if fishing is better then than at other times of the year but it is usually very good. The period between late September and the end of October is a great time to catch a real big fish. The biggest trout are rainbow/cutthroat hybrids. There are some between 10 and 15 pounds caught each autumn and every time I feel a strike in the deep water, I think it could be one of those monsters.
There are also some big brook trout in Henry's Lake. They move into the mouths of the streams and springs to spawn in the fall. I've had my best luck with them by getting out on the lake before the sun comes up. It can be a chilling experience in October and you might have to break the ice out of your guides in order to cast. The brookies usually stop hitting after the sun gets up except on cloudy days. They also seem to like brighter flies. I've had good luck on peacock wooly buggers with yellow or orange tails.
One of the secrets to success on Henry's Lake is getting the fly down to the fish. This often requires having a couple of rods set up, one with a slow sinking line and one with a fast sinker. In the shallows, early in the morning, the fast sinker will go down too quickly and you'll be hung up in the weeds all the time. In the deep holes, toward the middle of the lake, you'll need the fast sinking line to get down. The big hybrids hang out in these deep holes, so I'm told. One of the things I like about fishing in the fall is the requirements are pretty simple. You don't have to worry about what species of insects the trout are feeding on, even in the technical Harriman State Park. The two mayfly species I've already mentioned are likely the only aquatic insects you'll find on the water. There are also terrestrial insects like ants, beetles and hoppers, that hang out until cold weather finally freezes them out. A simple selection of flies will work on most of the water you'll fish here in Snake River Country.
I addition to the mayfly imitations, I like to carry a few Parachute Adams, Renegade, Yellow Humpy, Royal Wulff and Royal Trude dry flies. I really like the Renegade because it looks a little like a beetle and it works as well fished as a wet fly as a dry. Size 14 and 16 is best for the rough water you'll find on Fall River and sections of the Teton, Henry's Fork and South Fork.
My favorite nymphs include the Pheasant Tail, Gold Ribbed Hare's Ear and Prince Nymph. Another favorite is a simple pattern developed for the Madison called a Serendipity. These patterns also work great when tied in a bead head version. The gold bead gives a little more attraction and provides enough weight to keep the fly down. Some larger stonefly nymphs and dark wooly worms are also a good idea. A few years ago my good friend, Koke Winter caught 10 pound and 13 pound rainbows consecutively with a size 6 Black Wooly Worm in the Box Canyon. I wouldn't have believed that fish story but I was there and actually saw both fish. A small selection of streamers is also important. My favorites include a Silver Zonker, Olive Woolhead Sculpin and Clouser Minnow. Wooly Buggers are also important. Serious streamer fishermen frequently use a sink tip flyline to get down but I like to fish my streamers on a floating line. The boil made by a fast charging trout is usually enough to provide a respectable adrenaline rush.
As a young boy, growing up in this magnificent part of the world, I used to start bouncing off the walls in September and October because I tried to do everything. I feel sorry for my poor school teachers. I wanted to get as much hunting and fishing in as I could. If I could have been granted one wish it would have been to extend the month of October to 90 days. As I've matured I've come to realize that no matter where I am, whether on the banks of the Henry's Fork in the Harriman State Park or in the canyons of Fall River, I know I'm in the right place. There couldn't be any place better.