Wisconsin Winter Fly Fishing Tips

A Primer on Winter Fishing

You need two things to increase your success during our two states’ (WI & MN) winter trout seasons:

  1. First, you need some basic knowledge about trout behavior and insect populations.
  2. Second, you need to employ a certain flexibility in applying your craft at this time of year.

While mountain streams are sparkling clear and postcard perfect our local streams usually have some color.   Let’s explore the reasons for this difference.

Mountain streams are high gradient streams which have eroded their stream course to bedrock and the bedrock is usually igneous.

Local streams are lower gradient, flowing through valleys rich with alluvial soil and a edimentary bedrock. In addition, mountain streams are not very fertile because they lack nutrients and a mineral content. Our local spring creeks have both, receiving their nutrients from watershed run-off and spring seeps and their mineral content from the calcium carbonate leached from the limestone.

Water Clarity

OK, the next question is why are our local streams clearer in winter than in summer? Those of you who have fished the winter season will recognize this phenomenon:

When you see the lower Kinni in March it’s almost as clear as a mountain stream. The answer is that all those nutrients in our local streams foster algae growth and when the algae dies back in winter the stream clears.

Therefore, in winter you are more likely to find trout in deep water than shallow water.  Because the water is clearer they’ll seek deeper water to assure their safety. The successful angers in the winter season will be seeking out the deeper holes and fishing their nymph or scud as close to the bottom as possible.

Insect Activity

Most trout stream insects are herbivores. They’re specifically adapted to foraging leafy material or algae and the excrement of other organisms. Yes, you read that correctly. Thus does a stream cleanse itself.

The materials these insects forage are either called coarse or fine organic particulate matter (COPM or FOPM). All of these materials are found on the stream bottom, which is why you find the insects there. Since the water is colder in winter these invertebrates will be less active. As the water warms the insects become more active and more available to the trout based on their particular biology.

Even in the dead of winter insects will be available for the trout’s dinner.


Probably the earliest of these will be the winter stoneflies.   I’ve seen these insects struggling on the water’s surface in late January and various species will hatch through April.


On good spring creeks scud populations are abundant and, relative to other insects at this time of year, one of the more important trout foods.


Though it’s possible to find a Baetis dun on the snow on Valentines Day, the Baetis nymphs really begin to grow and become more active in March preparatory to their emergence in April.

And some time in April the Ephemerella nymphs will undergo the same behavioral changes prior to their emergence in May.

So, now you have a general idea of what to expect and when.

Where Trout Are Feeding

Now for flexible, a relative term if ever there was one. If the trout are in the deeper holes you’ll need to adjust your depth. If you tie you should either tie with tungsten beads, wrap heavier lead wire on your hook shank or add lead beads or split shot to your leader. You’ll need to move your indicator incrementally farther away from the fly until you start hooking fish.

You’ll also have to carry some flies that aren’t as heavily weighted because…guess what?…this year my informants tell me they’re finding fish in shallower runs and riffles.  And, as the water warms with Spring’s arrival, more and more fish will move into the riffles to feed. Be prepared.

As a final note, you will occasionally find fish rising to midges, winter stones and the sporadic Baetis in the middle of winter in even flows. These fish are small. The larger fish are in the deeper water. But, if catching four inch tiddlers is your idea of trout fishing heaven, by all means tie on a dry fly leader and go crazy.

Winter Ice

Somebody asked me recently if the mild winter we’ve has thus far was going to make things easier for the trout. The questioner was interested in the effects of ultra cold water on trout eggs and fry and that got me to thinking about trout survival again.

We all know that trout streams are special places because of the copius groundwater that keeps them cool. Ironically, the same groundwater keeps the stream relatively warm in winter: Cold is just a relative absence of heat. Good trout streams are usually free of ice in winter. You might see some shelf ice along the edges when it gets really cold but it won’t be frozen over like a warm water stream or a marginal trout stream will be.

Temperatures in a marginal trout are too warm in summer and too cold in winter. Water that is too cold will not incubate trout eggs. Too warm is lethal for trout, too cold is lethal for trout eggs…a double whammy.

There are two kinds of ice that can form in a trout stream, frazile ice and anchor ice.

Frazile Ice

Frazile ice is formed when the water super cools on very cold nights. Ice crystals actually form in the water column, further cooling the water. Even good trout streams can cool off at night under these conditions and a marginal trout stream has a lower buffering capacity because of its lack of groundwater.

Anchor Ice

Anchor ice is formed on the bottom of the stream during these same very cold periods. I can’t remember if it’s a separate kind of ice or whether it was frazile ice that anchors to the bottom. In any event the effect is the same…it covers the bottom and every living organism on it, from invertibrate larva to trout eggs. If they freeze, they die.

So, the mild winter we’ve been having will have some positive effects, although you might not be able to measure them. First, trout survival will be relatively high because water temps were improved and bottom-dwelling invertibrates didn’t die off.

Second, trout eggs didn’t get frozen either and they might actually hatch a day or two earlier than normal if the water temps were higher than normal. We’ll probably never notice these results, although we’ll all admire the condition of the first trout we catch this season. We should, because while it’s a pastime for us, a pleasant diversion, for a trout it’s a life and death struggle.

Strike Indicators and Fishing Deep

Have you ever fished Hay Creek near Red Wing? If you have you know it ranges in width from 6-15 feet. How deep is it? If you’ve fished often you know that it’s loaded with fish, yet most winter anglers are happy if they catch three or four trout there on any given outing. How about a nice big rhetorical “Why?”

Gordy fished it two days in succession the week before. He picked up a fish here and there before reaching a pool he anticipated fishing. He told me that no matter how carefully he drifted his nymph through the pool, he didn’t start picking up fish until he’d raised his strike indicator to eight feet! He caught about a dozen fish from that hole and finished the two days with over fifty fish.

So the answer to the rhetorical querie posed earlier is that you’re not fishing deep enough.

In winter when the water temperatures plummet south of 40 degrees F, trout really need to conserve energy and will not move far for food. Even though the invertebrate larvae are active, grazing and growing through a number of instars, they are only available to the trout on the bottom.

OK, occasionally you might see a winter stonefly or some midge activity, but for the most part, insects don’t hatch in the middle of winter, or hadn’t you noticed? Ergo, you must fish your nymph on the bottom, adding or subtracting weight and raising or lowering your strike indicator as conditions dictate.

The key to this winter fishing is to adapt. So, take a reality pill and do what Gordy says: Adjust to conditions.

I first encountered the concept of changing conditions and the need to adjust to meet those conditions in the 1981 book, JOE HUMPHREYS’ TROUT TACTICS. Humphrey is bombastic, but he hammered home the point until even I got it.

Joe Humphreys’s Trout Tactics: Updated & Expanded

  • An updated classic now available in hardcover
  • Tips on casting, nymph and wet fly patterns, hints on controlling fishing depth, and much more

Without belaboring the point. Let me just offer you two concepts. First, in dry fly fishing what matters most is the diameter and length of the tippet. It’s these two factors that allow you to best compensate for surface currents in order to get a drag free float.

Second, in nymph fishing what matters most is getting the fly down to the fishes level. To do that you have to adjust the amount of weight on the leader as well as adjust the strike indicator to the correct depth.

There are other factors of course, like fly selection, leader design, casting ability and approach. But, other than casting ability, the two factors I mentioned earlier are supreme. If you’re not willing to adjust your tippet when fishing dry or adjust your depth when nymphing, you’ll be missing fish.

Reread TROUT TACTICS if you need a refresher…it belongs on every serious anglers book shelf.

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