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Thunder River

PMDs on the Roaring Fork, Colorado's best freestone river.

Thunder River

In spring and early summer the Roaring Fork is a big, brawling river, but even then there are opportunities for wade fishing. Look for trout along the edges of riffles and in shallow water along the bank. (Landon Mayer photo)

This article originially appeared in the June-July 2011 issue of Fly Fisherman magazine.

The Roaring Fork River was once known to the Ute Indians as the Thunder River, and its fishing is no secret to serious Colorado fly fishers. Dropping fast in elevation from its headwaters in Independence Pass, the river widens after receiving tributaries like the Fryingpan and Crystal rivers. With a mix of private and public water along its 70-mile journey to the Colorado River, there is plenty of water to target trout by drift boat, making it the most popular float-fishing river in the state. As a result, many people overlook it as a wading destination, and prefer nearby foot-friendly rivers like the Fryingpan because of the Fork’s sometimes intimidating size and intermittent access.

Another peculiarity is that while a full-blown Gore-Tex hatch often breaks out during Green Drake time (first week or two of July), other hatches go relatively unnoticed. The thrill of seeing a heavy trout gulp down a mayfly with wings you can spot from across the river is hard to beat, but other hatches bring different thrills—often with better results. Massive swarms of caddis in the spring, early spring and late fall Blue-winged Olive hatches, and Pale Morning Duns from June through late August produce outstanding fishing during almost every season, leaving the Green Drakes as only icing on the cake.

Thunder River
John Barr’s PMD Flashback Emerger is a deadly imitation of a rising and emerging Pale Morning Dun. Use it as a dropper below a highly visible PMD Sparkle Dun to catch suspended trout gorging on the midday hatch. (Landon Mayer photo)

Three Rivers

Colorado 82 parallels most of the river from Independence Pass north to Glenwood Springs. Most fly fishers break the river down into three sections: the upper river from Aspen to Basalt, the middle river from Basalt to Carbondale, and the lower river from Carbondale to Glenwood Springs, where it finally meets the Colorado River.

Upper river. Mimicking a small mountain creek above the city of Aspen, the headwaters of the Roaring Fork have good populations of brook trout at higher elevations, with rainbows and brown trout up to 14 inches as you move downriver. The section from Woody Creek Bridge upstream to McFarlane Creek was the first water in the state designated as wild trout water. Today that label holds true, and there is plenty of public access along the Rio Grande Trail and through Jaffee Park.

The river is also open to the public well upstream in White River National Forest (Difficult Creek to Independence Pass) for about nine miles. This intimate setting is not known for large fish, but for its endless action with attractor drys, and for wild aggressive trout. It is a great break in the heat of a summer day to hit this section of the Fork, which is always cold from its high-elevation origins.

High-stick the pockets and seams with Fat Alberts, Puterbaugh’s Caddises, and Mini Hots. Remember to think small (#14-16) so the trout can actually fit the attractors into their mouths. 

Middle river. Possibly the best area to wade, the river between Basalt and Carbondale is narrow enough in many sections for walking anglers to cover most of the water effectively, and the fish are bigger.

The Fork has some of the slickest rocks in the state, so use caution, a wading staff, and metal studs to stay on your feet in this area.  

At the confluence with the Fryingpan River in Basalt, the river gains flow, nutrients, more quality holding water, and better hatches of midges, caddis, PMDs, BWOs, and stoneflies. This abundance of insects in the long riffled runs and tailouts can keep you busy with trout for hours in just one 100-yard section. So don’t get stuck in a glory hole—give yourself the chance to explore the many miles the middle section offers.

The north side of the river in Basalt has three miles of public water between the upper and lower bypass bridges off Colorado 82. Parking for this section along 2 Rivers Road is obvious. Farther downstream, Hook’s Bridge provides a short stretch, with the parking off Willits Lane, as well as a 1.5-mile stretch off Valley Road. Both areas have north shore access only.

Reach Blue Creek Ranch Access and Catherine Bridge Access by turning left (as you travel downstream) at Catherine’s Store Road and parking at the parking lot. If you decide to float, a good put-in is at Hook’s Bridge, and the takeout is the Carbondale Bridge. By raft it is approximately 12 miles—drift boats are not recommended.


Lower river. From Carbondale, the addition of the Crystal River creates ideal water for drift boats, although wading is still productive along the edges. By boat there are numerous runs where you can spend time doing laps, and there are areas where it’s best to concentrate on rocks, eddies, seams, and tailouts.

Thunder River
Floating is the most popular way to fish the river below Carbondale. In the fall and in spring when the water is high, throw streamers into the sheltered water near the banks to find large trout. In lower flows, drifting nymphs along the bottom pays dividends. (Landon Mayer photo)

With both resident trout and seasonally migrating fish from the Colorado River, the lower river has the largest rainbows, cuttbows, and browns averaging 14 to 18 inches, and numerous fish beyond 20 inches. If you are looking for bigger fish, this is the place to do it.

The best floats are from Carbondale to Westbank Bridge (8 miles), or Carbondale to Two Rivers Park on the Colorado River in Glenwood Springs (14 miles). During prime caddis season, it is worth the trip to Two Rivers Park, as the lower reaches have excellent evening dry-fly fishing.

Four Seasons

Spring. As the winter days gradually disappear, quality fishing blooms on all three sections of the Fork. The water near Glenwood Springs warms first, and most hatches begin there and travel upstream. Typical flows pre-runoff are 400-600 cubic feet per second (cfs) in Glenwood, 175-350 cfs below Basalt, and 100 cfs near Aspen.

As the snow melts and the flow increases on the Crystal and Fryingpan rivers, as well as smaller tributaries, it does not take long for the river to blow out. This typically occurs during May, but can change from year to year with Colorado’s unpredictable weather.

As the days get longer, the hatches intensify with Blue-winged Olives, small black stoneflies, and a massive caddis hatch before or during spring high-water events. The so-called Mother’s Day caddis hatch actually begins in the Colorado River in April and proceeds upstream into the tributaries in early May.

Somewhere there is a massive caddis hatch on Mother’s Day, but you need to do some detective work to find out where, and consider yourself lucky if  the water is clear enough to find rising trout.

In the spring, many rainbows migrate upriver from the lower Roaring Fork and the Colorado River. Don’t wade or fish in shallow riffled tail-outs where wild rainbows may be spawning. The future of the fishery depends on successful wild trout reproduction.

Instead, concentrate on deep water below the riffles, meaty runs, and pocketwater to target hungry browns and avoid interrupting spawning rainbow trout. I use streamers in the spring to hunt for large browns that have traveled up from the Colorado River, following the rainbows and the moving spring hatches. Some great patterns are Autumn Splendors, Slumpbusters, Will’s Stinging Sculpins, and Lawson’s Conehead Sculpins (#6-10).

For a nymph rig, start with an egg as an attractor, and trail a midge or Blue-winged Olive imitation such as an STD or BLM (#18-22).

Summer. For those familiar with the Roaring Fork’s Green Drake hatch, there’s no need to explain what a spectacular sight it is to see size 10 to 14 mayflies engulfed by aggressive trout. It is truly one of Colorado’s epic hatches—if you hit it just right.

However, many people are disappointed  every season due to the short seasonal duration of the hatch, and the often brief daily time frame—typically late evening into darkness. (The hatch in theory can begin as early as noon on gloomy, overcast days, but on regular Colorado bluebird days you’ll probably have to wait until dark.) The Green Drake hatch can make you feel like you are chasing a mythical insect if you are not there at the right time or else stick around until after dark.

The opposite is true of perhaps the most productive and underrated hatch of the summer season—Pale Morning Duns. PMDs hatch on sunny days from midmorning to early afternoon all through July and into August some years.  

While you do not always see fish rising on the surface, you can be effective at every water level from top, to middle, to bottom throughout the day during the PMD bite. One of my favorite ways to rig for this sunny event is using a dry such as a #16-18 Mathews PMD Sparkle Dun, with 3 feet of 5X dropper tippet attached to a beadhead  Barr Emerger or Juju PMD slightly weighted to reach suspended trout.

Thunder River
Will Sands says Roaring Fork trout feed heavily on PMDs and become focused on them because they hatch for several hours of the day during two months of the summer. (Landon Mayer photo)

You can also swing soft-hackles like Craven’s PMD Soft-Hackle or a soft-hackle Hare’s Ear to target trout focused on emerging PMDs. [See Dave Whitlock’s article “Old School” on page 40 for more information on fishing soft-hackles. The Editor.]

Local experts like Will Sands of Taylor Creek Fly Shop know firsthand the results of concentrating on this sometimes overshadowed mayfly. “What separates the PMDs from other mayflies is how long the hatch lasts most days from late morning into the afternoon,” he says.

“PMDs on the Fork often do not provide great dry-fly action because so many days are bright and sunny, but suspended fish crush and chase nymphs or emergers recklessly. You can often sight-fish to suspended fish or see many of the subsurface strikes. But the PMDs hatch for so many hours of the day the fish really get keyed on them and in the right conditions they will take the duns as well.”

The PMD hatch is generally heaviest from noon to 3 P.M., and spinner falls can occur any time of day from early afternoon until evening. Look for clouds of spinners hovering over the riffles, and carry #14-16  Rusty Spinners for the evening rise, which can be complicated by simultaneous spent PMD spinners, hatching caddis, Green Drakes, and occasionally Golden Stones.

Fall. September and October in the Roaring Fork Valley supplies some of the most breathtaking scenery in Colorado. With a steady population of rainbows, and migrating brown trout and whitefish from the Colorado, the fishing can heat up to where many anglers refer to this season as “Bugger Time.”

With flows near Glenwood from 450-800 cfs, you can pursue trout by foot or boat, but the most effective tactic is to float and throw streamers toward the banks. This allows you to cover more water, trigger more strikes, and find the most aggressive fish in the river.

Sands says the dry-fly fishing in late fall can also be outstanding. “Blue-winged Olives and midges dominate the fall season, but there are also sporadic October ‘pumpkin’ caddis hatches that can produce fast and furious surface activity,” he says.

“Egg patterns are also effective as the browns and whities spawn during the fall. Prince Nymphs, Autumn Splendors, and Stinging Sculpins are my favorite patterns for this season.”

Whether you are nymphing, using streamers, or looking for dry-fly fishing, fall is a good opportunity to practice all three disciplines in comfortable weather.

Winter. With low flows throughout the system from December through March, some areas are accessible by foot where it would be impossible during high flows.

The river drops below 400 cfs in the cold season and the fish move out of the shallow and fast water, increasing the concentration of trout in the deep runs and wintering holes. Crowds are at a minimum and on an overcast, snowing day in March you can experience solitude and unpressured rising fish feeding on midges and Blue-winged Olives.

The best areas on the coldest days are from Basalt to Carbondale, where the influence of the Fryingpan is the greatest. The upper river toward Aspen is usually frozen.

For nymphs, consider small Pheasant Tails, BLMs, STDs, eggs, and stonefly imitations like Prince Nymphs or 20-Inchers. My starting rig is often a #14-16 Prince Nymph trailing an emerging midge like a #18-22 Rojo Midge. Adjust the color of your midge, if needed, throughout the day or swap it for a Blue-winged Olive.

When trout are confined due to low flows, deep pools are great areas to find concentrations of trout. The slow water is perfect for spotting tiny midge drys during hatches that typically occur on cloud-insulated days.

It’s these late winter dry-fly days that close the loop, making the Roaring Fork a true four-season fishery, and one of the best freestone rivers in the state. Whether it’s PMDs in the summer, streamer fishing in the fall, or massive caddis hatches in the spring, the Fork has something for everyone.

PMD Patterns for the Roaring Fork

PMD Flashback Barr Emerger

Thunder River
(Charlie Craven photo)

HOOK: #16-20 Tiemco 2487.
THREAD: Light Cahill 8/0 UNI-Thread.
TAIL: Brown hackle fibers.
ABDOMEN: Olive-brown Superfine dubbing.
FLASHBACK: Medium opal Mirage Tinsel.
WINGCASE: Pale yellow hackle fibers.
THORAX: PMD Superfine dubbing or dyed beaver.
LEGS: Leftover butts of wingcase fibers.

PMD Soft Hackle

Thunder River
(Charlie Craven photo)

HOOK: #16-20 Tiemco 100SP-BL.
THREAD: Light Cahill 8/0 UNI-Thread.
TAIL: White Fluoro Fiber, three strands.
ABDOMEN: Sulphur yellow Superfine dubbing.
WING: White Fluoro Fiber.
HACKLE: Blue dun hen neck hackle.
THORAX: Sulphur yellow Superfine dubbing.

Craven’s Juju PMD

Thunder River
(Charlie Craven photo)

HOOK: #16-20 Tiemco 2488.
THREAD: 16/0 white for abdomen, dark brown 8/0 UNI-Thread for thorax.
TAIL: Mottled brown India hen saddle fibers.
ABDOMEN: Two strands of dark brown and one strand of orange Super Hair.
FLASHBACK: Medium opal Mirage Tinsel.
WINGCASE/LEGS: Brown Fluoro Fiber.
THORAX: Dark brown 8/0 UNI-Thread.
COATING: Clear Cure Goo.

Thunder River
Getting There: Basalt is 180 miles west of Denver via I-70 through Glenwood Springs, and 177 miles through Leadville and Independence Pass. The best wading areas are near Basalt off 2 Rivers Road and along the Rio Grande Trail at Jaffee Park and Stein Park. (David Deis graphic)

Landon Mayer ( is an author and fly-fishing guide. 

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