This is ‘the’ time.
I know it’s not the best time to catch a lot of bass with a fly rod.
But, if you want to catch good bass, big bass, those heavy fish that many fly fishermen never see, now is the time.
You see, bass are very predictable in the winter. Much more so than in the warmer months. Once you find them, they will likely stay there until the water warms. If you are lucky or good enough to find a concentration of good fish, you can return to them again and again throughout the cold water season.
The keys to help you find fish this time of year are water temperature and the topography of your lake (what some of us like to call structure).
Of course, you’ll need open water. If your fly is likely to bounce when it hits, then I can’t help you much. But if you have open water, and if the temperature someplace on your lake is hovering in the low to mid 40s, you can catch bass. Maybe not a lot of them, but you can some catch good bass.
You’ll also need relatively clear water. That’s usually not too much of an issue in he winer, but if your lake is cold and muddy, find another place to fish.
The areas you are looking for are those steep banks that drop directly into the channels and deeper sections of the lake. You’ll want to find areas that drop fast from the surface down to twenty-five or more feet deep. If your lake isn’t that deep, fish the deepest areas you can find. Once you find these steep banks, look for points that intersect them, or prominent channel bends, anything that will differentiate a portion of the bank from the rest of the area. Bass like edges, and such areas offer this to them.
What the fish will be doing is holding on an edge or point along these steep banks. This allows them to move easily up or down in the water column without losing contact with the structure. The bass will move upwards if the water is warming at the surface, downwards if it’s getting colder. They won’t move much latterally, and they tend to group together at this time of year.
If you have a boat with good electronics, you can find these areas easily. The capabilities of modern sonar are amazing, and sometimes you can easily find the fish with them. If you are shorebound, you’ll have to eyeball the area generally, then learn it by fishing it. Just make sure that from where you will be standing you can cast to water that’s at least twenty-five feet deep or more.
This is slow, methodical fishing. You’ll need a sinking line for most of this type of fishing. Use the fastest sinking line you can throw. Bass are going to be close to the bottom most of the time in the winter, so you need to fish as close to it as you can. If you are going to fish from a boat or float tube, be sure to have an anchor and know how to use it. It takes a while for any fly line, even the really fast sinking ones, to get down to twenty or more feet of depth. If your boat is moving, it will take even longer.
Until you find the depth the fish are using, make your casts across the structure. Put your boat in shallow water and cast to deeper areas. It’s easier to work your fly up the incline and keep it close to the bottom than it is to do the reverse. Once you determine the depth the fish are using, move out to that depth and cast parallel. This gives your fly more time in the area the fish are actually using, and ups your odds considerably.
If you are fishing from shore shallow to deep is pretty much your only option. But optomize your fly’s time in the strike zone by casting only as far as you need to to reach the fish. Angling your cast somewhat can also help with this.
You’ll want to count your fly down on every cast. Sometimes the only way you’ll know you’ve been bit is that the fly will stop sinking too soon. Let whichever fly you choose to use sink all the way to the bottom. Retrieves that work best this time of year are usually slow ones, but there is still some room for experimenting with the whole ‘slow’ thing. Short quick strips, short slow strips, long slow strips, just gently and slowly lifting the rod tip, etc., can all be effective based on the mood of the fish. Pauses between movements are a constant, though, and most strikes happen as the fly settles after you’ve stopped moving it.
Strike detection can be tough. Sometimes the strikes are subtle. You’ll need to pay attention and strike at any change in the feel of your line. Often it’s just a heavy feeling or the reverse, it will feel like the fly is gone. Sometimes, though, especially with cold water smallmouths, the strikes are savage.
Depending on what is on the bottom of your lake, you may need weed guards on your flies. Any flies for this type of fishing should be tied so that the hook points ride upwards, whether you use weed guards or not.
Fly selection is always pretty subjective. I stick with simple leech type patterns in either crawfish colors or shad colors. Any pattern you feel comfortable with will do just fine. Minnow patterns like clousers, diamond hair minnows, etc. are all good choices. It’s really hard to go wrong with a large all black wooly bugger.
Fly size is something else. Bigger is usually better this time of year. Bass instinctually do the energy value of prey versus the energy expended to catch it equation for every meal. In the colder water, they eat less but seem to prefer a bigger meal. Flies that are tied to be three to five inches long should suffice.
I don’t usually weight my flies for this kind of fishing. I use the line to get the fly down. This give a bit more of a subtle action to the fly itself.
Another little trick is to use a shad or chartruese colored fly with a bit of foam at it’s head. All I usually do is just fold a piece of foam over the fly’s head and glue it in place with some CA glue. This will cause the fly to dive towards the bottom with each pull, and then float upwards on the pauses. Works especially well on smallies that are holding on rocks and largemouths anytime there are shad around.
Sometimes the fish will hold off the bottom. If this happens you can steal a tactic from the spin fishermen that’s so incredibly effective that a lot of trout fly fishemen that fish lakes have also appropriated it. In many areas it’s called a float and fly, and you can do it very well on a fly rod with a long leader and a strike indicator.
I tie my flies for this fishing on 90 degree jig hooks, keeps the fly horizontal in the water. I’ve used leaders up to eighteen feet with this technique, but it’s easier to throw with ten to twelve foot leaders. Same flies, but just suspend under a good indicator. Works best when there’s some chop on the water. Cast it over the fish, and let the wind and waves move and work the fly.
Don’t let a little cold water and some snow on the ground keep you from bass fishing. You won’t get many fish on poppers and gugglers this time of year, but you can still catch bass. And some good ones.
Good Luck!
Buddy
Got the same problem chucker. Like I tell everyone - you can fly fish in Iowa in the winter time - just takes a long time to cut the hole. 
