Deciphering Winter Tailwaters

Deciphering Winter Tailwaters

It’s no secret that Colorado is blessed with an abundance of world-class tailwaters that support a rich and diversified aquatic life as well as impressive populations of trout. One of the advantages to a tailwater fishery is they remain fishable year-round. Free-flowing streams on the other hand are typically clogged with ice for several weeks (months) during the winter, which is a huge disappointment for freestone enthusiasts.

Strange as it might sound—winter is one of my favorite times of the year to fish, especially when I’m seeking a little solitude. Winter fishing is by no means easy—but those anglers willing to battle the elements typically find a few cooperative fish on just about any outing.


The good news is that die-hard anglers suffering from cabin fever can benefit from the thermal stratification that takes place within in the reservoir itself.  Aquatic biologists refer to this phenomenon as “winter warm—summer cool” because during the winter the warmest water flows from the base of the dam (the surface is frozen) and during the summer the exact opposite occurs. Understanding this paradox is the formula for success on many of Colorado’s watersheds.


Throughout the winter, the water closest to the dam provides the best opportunity to fool fish, but it quickly cools down in the mileage below the tailrace. Several miles below the dam it’s not uncommon to find slush ice or anchor ice (or find the river is completely frozen) because of the rapidly declining water temperatures. Being in the right place, at the right time, with the proper techniques is critical for success. Here are a few tips to help winterize your tactics and elevate your game to the next level.


Finding Winter Trout


One of the greatest challenges during the winter is locating fish that are willing to eat. Successful anglers must concentrate their efforts in the slow, deep pools and tailouts where lethargic trout stack up during the winter. Its important to avoid fast currents and target the soft water margins as these areas provide trout with the greatest amount of food while expending the least amount of energy.


The biggest hurdle to overcome is finding a feeding fish. For every dozen trout you locate, only a fish or two is actually engaged in the feeding process. Look for fish that are suspended in the water column, particularly in the transitional zones, or trout that are sweeping back and forth intercepting midge pupae, as these are good indications that the fish actually feeding. Fish that are hugging the stream bottom are typically non-feeders and should be ignored.  This is a huge tip as you can waste a lot of valuable fishing time on trout that are not eating!


The best window of opportunity is between 10 a.m. and 3 p.m. Get in a habit of carrying a digital thermometer and checking the temperature on a frequent basis. If the water temperature is below 38 degrees, chances are good you’ll struggle catching fish. If the water temperature warms up a few degrees, it often triggers a midge hatch that produces a small feeding frenzy. It’s important to capitalize on this opportunity while you can because the window of opportunity closes quickly.


Don’t be fooled by inclement weather—some of the best fishing occurs when it’s nasty out. I have experienced some of the best dry fly fishing during a snowstorm when midges have blanketed the water.  Subdued light and high humidity stalls the development of these aquatic insects keeping them on the water longer. This is true with both midges and blue-winged olives. It’s not uncommon to see “olives” hatching until the latter part of November or first week of December on many tailwaters in Colorado.


Less is More


During the winter, it is important to think simple, sparse, and most importantly small! The bulk of a trout’s diet during the winter months is midges. This means anglers need to familiarize themselves with a midges’ lifecycle and come prepared to imitate the various stages of their development during the winter. Oftentimes, the difference between catching a few fish, and not catching fish at all, is using a size 24 or 26 midge imitation, instead of a 22.


I strongly recommend carrying a thorough selection of pale-olive and red midge larva, brown and black midge pupae, and a few adults in the event you find some rising trout during the height of a midge emergence. Some of my favorite patterns include: Size 22-26 Pure Midge Larva, Mercury Blood Midge, Top Secret Midge, Black Beauty, Manhattan Midge, Bling Midge, Matt’s Midge, Griffith Gnat, and Parachute Adams.


Although it’s not the norm, we do have one tailwater in Colorado where we find blue-winged olives to be a factor during the winter months. This is the tailwater below Pueblo Dam (Arkansas River), and nifty little fishery that has a diverse aquatic life.  Pueblo Reservoir is not as deep as many western tailraces, coupled with it being in a warmer geographic locale, so the water temperatures are warmer than most tailwaters.


I would carry a few Baetis nymphs and blue-winged olives (duns) imitations in your arsenal of flies to cover your bases. Some of my favorites include: Size 20-24 Stalcup’s Baetis, JujuBaetis, Mercury Baetis, Chocolate Foam Wing Emergers, Sparkle Wing RS 2’s, Parachute Adams and Mathew’s Sparkle Duns.


It is important to downsize your tippets to 6 and 7X during the winter months.  I typically use 6X fluorocarbon for my nymphs and 7X nylon for my dry flies. Make sure you carry and extra spool of each in your vest or lumbar pack, as running out of tippet at the most inopportune time can make or break your success.


The Lead Attraction


In Colorado, a two or three tandem nymphing rig is the norm on most tailwaters. I personally use three flies, which allows me to run an attractor trailed by two nymphs to match any evident hatches. During the winter it’s hard to go wrong with a red larva, micro egg, or red Flossy Worm as an attractor the vast majority of the time. These patterns typically draw attention to the droppers and help separate your flies from the crowd. It’s important to check your local regulations with regard to tandem rigs—in some states you can only use two flies in your nymphing set-ups.


Choosing an attractor can be a double-edged sword however.  In some cases, (low, gin-clear flows, slow moving currents, flats, etc.) choosing the right attractor is a game changer.  For instance, if the flow is 50 cfs (in comparison to 200 cfs), a bright and gaudy fly might become a red flag and spook more fish than attract so each scenario requires some fine-tuning. It’s important not to get trapped in a rut with a “one size fits all” mentality. If the flow is low, I typically use a size 18 or 20 Rainbow Warrior, Mercury Flashback Black Beauty, or other flashy nymph as my attractor then trial two smaller nymphs (size 22-26) below it. This approach has proven itself to be deadly when the trout have a long time to inspect your artificial offerings.


I choose my droppers based on the prevailing conditions. If a midge hatch is in progress, I tend to use two pupae, if the hatch is sporadic, I might use one larva and one pupae, and so on. Mix things up as you see fit based on any visual observations.


Understanding the Nuances


Sometimes it’s the little things that add up to big things. Nothing could be further from the truth with regard to success during the winter. The old cliché “The difference between a good angler and a great angler is one split shot” is not far from the truth. 


It is important to constantly adjust your weight to keep your flies in the correct feeding zone. For instance, during the height of a midge hatch, your flies should be fished mid-column, and to the contrary, if there are no visible adults in the air, you should consider fishing your nymphs closer to the substrate.  Too much weight is as problematic as not enough; so it’s extremely important to constantly adjust your weight.


I recommend using a yarn strike indicator because the takes during the winter are extremely subtle. Yarn stacks the odds in your favor in comparison to bobber-type varieties. In slow moving currents, the strike indicator may only slow down or twitch, which is an indication a trout has taken your fly. If anything causes your indicator to hesitate at all—set the hook immediately! I recommend setting the hook downstream at a 45-degree angle, which helps pull the flies back into the trout’s jaw. The hook set should be a firm stroke but a short range of motion, otherwise; you’re at risk of breaking your tippet or pulling the fly out of the trout’s mouth.


Dress in Layers


Staying comfortable may be the biggest tip I can give you during the winter. If you get cold, the experience deteriorates quickly. I typically begin by wearing SmartWool socks, fleece mid layer bottoms, and fleece pants underneath my waders. This is a great base layer that keeps you warm under the most challenging conditions.


I typically wear two layers of mid layer fleece on my upper body depending on the conditions.  Over that, an insulated PrimaLoft vest or coat keeps your core warm and comfortable without too much bulk. I recommend wearing a Gore-tex jacket in the event it becomes windy or snows (rains).  Make sure you carry two pairs of gloves (one flip mitt and one fingerless) and a stocking hat to keep your hands and head warm. I typically wear my stocking hat over my ball cap to eliminate overhead glare.


Fishing in the winter is only as difficult as you make it. If you dress warm and have the right attitude fishing in the winter is a blast. There are certainly trade off’s and compromises to the winter season—but in my opinion—the rewards are worth the effort.


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