Stone Cold: How to Fish Winter’s Big-Bug Hatch

February 12, 2024 By: Kubie Brown

“Variation of Carl Pennington’s D-Rib Golden Stone Nymph” ~ Tie and image by Freddy Block

For many fly anglers, winter is a time to tie flies, watch fishing videos, and prep gear while they wait for spring to arrive. They sit curled up on the couch and look gloomily out the window like a dog waiting for their owner to come home while the seemingly endless white cold of winter scratches and claws at the walls trying to get in. Even when they can’t stand it any longer and brave the icy waters, winter fly fishing is often about drifting frustratingly tiny flies past sluggish, lock-jawed trout repeatedly, hoping for a strike. However, there is another option often overlooked by anglers. One where you can fish larger bugs that, under the right conditions, winter trout will pounce on like starving coyotes on a three-legged rabbit. I’m talking about winter stoneflies.

The World of Winter Stones
Most rivers have a regular procession of stoneflies hatching during the winter months. Yet, for the most part, these hatches are ignored by both anglers and fish during the early winter as they are generally made up of small bugs hatching in sparse numbers. However, as the winter goes on, these bugs begin to draw more consideration from trout who have been living on a limited diet of midges and other micro insect larvae.

Stoneflies are larger insects that offer a more significant meal for fish. On warm mid-winter days sluggish, energy-conserving trout will swim well out of their holding lies to snatch a drifting stonefly nymph out of the current. This presents a great opportunity for some hot deep-winter fishing action so long as you’re fishing with the right flies and techniques.

Equipment and Fly Patterns
Winter stonefly fishing is a very different animal from splashing giant foam patterns down in rapids or bouncing monster nymphs along bank edges like we do in the spring and summer. It’s a game of subtlety and discretion that sees you slowly working flies in low, clear water and trying to tantalize reluctant trout into coming out to play. Standard 9 foot, 5-weight rods will work just fine for the job, but it also can be a great time to pull out a 10 foot rod if you have it. The extra length will give you more reach and line control in what can be some hard to reach parts of the river.

Leaders and tippet for winter stonefly fishing should be lighter than the 1x to 3x suspension cable used for summer stonefly fishing. In winter, lighter 4x to 5x fluorocarbon leaders and tippet will have less chance of spooking trout. However, you’re not going to want to go much lighter than that as strikes from trout can still be quite aggressive and you’ll risk breaking fish off if your line is too light.

Winter stonefly patterns can be extremely varied. In some Western rivers, larger stoneflies like salmonflies can have a three or four year life cycle, meaning that the nymphs can come in many different sizes. In other places, you may have a mix of small black winter stones and/or golden stones that make up the bulk of a river’s population. Since most stoneflies are the same size and shape, though, you really only need three or four different patterns in a couple different sizes to get on top of the fish.

For the most part, small dark stonefly patterns like the Beadhead Biot and the Twenty Incher in sizes 8 to 16 are going to cover most of your bases. However, in rivers where larger stoneflies are present or when trout are showing a bit more aggression, larger patterns like Pat’s Rubberleg in sizes 8 to 4 can really help you connect with some bigger fish.

Fishing Winter Stoneflies
Deep holes are always going to be the first thing you should pay attention to during any sort of winter trout fishing. In low-clear water, these deep spots of slow moving current become sanctuaries where trout can easily hold and feed. However, it’s important to remember that when fishing with winter stoneflies that not all holes are created equal and by focusing your attentions on specific areas of the holes with specific techniques, you can be much more productive.

Stoneflies have periodic intervals of activity during the winter and areas where they move and concentrate in and around. They’ll gather around logs jams, brush piles, and other decaying plant matter in the middle of the river where they can find food and some species also begin to push up onto gravelly flats and bank edges to breed. On cold days, set up an indicator rig with a pair of stonefly patterns and a couple of split shot and drift it through the center of any deep hole that is directly downstream of these flats and mid-river debris. Try to drop the flies as close to the top of the hole as you can and then mend heavily so that the flies will sink quickly and drift the entire length of the deep water.

On warmer days, in the mid to upper 40s, both the trout and flies will be more active and you’ll have better luck focusing on outside turns. These are areas of faster, shallower water that run along the edges of the deep holding water, acting as conveyer belts where trout can dash in quickly and grab a meal. You can drift these outside turns with shallow indicator rigs or by casting and drifting stoneflies on a tightline. It can also be productive to swing stoneflies through these spots as well. Do this by casting slightly downstream into the shallow edges of the turn, making a mend so the flies will sink, and then tightening up your line so that the stoneflies drift through the outside turn and out into the hole. This can be a great way to get your flies absolutely smashed by a hungry trout jumping on a big bug opportunity.

Fight the Cold
Winter is always going to be a time that we fly anglers must grit out teeth and bear. The sparkling rivers we love so well are locked up in a frozen hiatus and often the only thing that can get you through is knowing that spring is on its way. However, if you’re not the sort who can just sit idly by and wait, fishing winter stoneflies might be just thing to get you on the water where you can look forward to warmer days with a bent rod and some big trout.