Howdy,
Winter fishing has its own unique set of challenges. You have to deal with the weather and a number of other factors - rain, snow, wind, air temperature, water temperature, river levels, river flow, water clarity, etc. Getting all of those factors to align for a “perfect day” is rare, or impossible.
Around here we hope for a “fishable day”, one in which it isn’t raining hard, the rivers are dropping, the flow is moderate and the clarity is “steelhead green”. We also hope for water temps above 40 degrees and the air temp above 45 degrees. This is as close to perfect as it gets and it happens 3 or 4 times during the winter. Those days usually coincide with a day when your schedule is full – meetings or big projects of some sort at work, travel plans that aren’t near water or other commitments you just can’t get out of.

Wild Rainbow caught in January 2010
In the winter, the fish aren’t very cooperative either. They are cold, lethargic and their primary interest is conserving energy to sustain them until spring. They will eat, but the food has to come to them. They won’t move much to find it. Moving burns precious energy.
To have fishing success, we need to think differently in the winter. We can’t just walk up to the waters edge and watch for rises, hatching bugs and other signs of where fish are and what they’re dining on. We have to make assumptions about location and food sources. We can do some investigation using a seine and/or overturning a few rocks. Hopefully we’ll find some bugs that will give us a clue as to what food source is in the water. That may or may not help tell us what’s being eaten, but it will tell us what is available. If we are fortunate to catch a single fish, we can suction it’s stomach (very carefully please) and then find out exactly what that fish is consuming.
That’s all well and good if your target species is trout, but if you’re stalking steelhead, entomology won’t do much good. Since the big ocean going fish don’t eat (or eat very little), food isn’t their reason for being in the rivers – they are in the river system to spawn. You have to get their attention by other means. There is a “feeding instinct” that can be triggered, but a lot of the time you’ll get a better response from them by triggering their “protection instinct”. Steelhead like to “camp out” and establish a territory which they will defend. We can also prey on a steelhead’s curiosity, as they like to “check things out” on occasion.

December 2009 Half Pounder Wild Steelhead
Now that we’ve determined what we’re going to use to entice a fish to strike, we need to figure out where and how we’re going to present it. Under “perfect” winter conditions, the fish will hold in similar places that you’d expect during the rest of the year, but remember, we seldom have perfect days in the winter. That gentle riffle that produces fish for you in the summer is now a raging torrent with an extra 1,000 cfs of water rushing through it, that pool that was clear and glassy is now a boiling cauldron of whirlpools and undertows, littered with branches and other debris.
Look beyond your normal “honey holes” and find water that a fish might prefer. Think about where you normally find the fish, then search for those types of conditions - water moving at the correct pace, seams between slow and fast water, cut banks, structure, etc. Those places do exist, even in crappy conditions, you just need to find them.
Finally, once you have found the right fly AND the right location, present that fly so that it gets to where the fish is holding – put it in front of their noses so they don’t have to move to get it. Vary your depth, speed and angle until you find the combination that works. You can have success fishing in the winter, it’s just measured differently. It’s not so much about quantity or size in the winter, it’s often more rewarding because you had to think and work a little harder. Even if you come home empty handed, you’ll have spent some time learning new things about the fish and the water. You’ll be a better angler because of it and have even more success in the coming months when things are “easy”.
Tight Lines!
Dave