Southwest Montana Fishing Report Overview
Fishing area waters has settled into a very predictable winter pattern. Days are short, water temperatures are cold and trout are now largely on maintenance diets and are primarily focused on conserving energy. Ice shelves and slush in rivers can be an issue during cold snaps but there are still plenty of options when temps are in the upper 20s or above (colder temps result in guides icing rapidly and make fishing difficult. The best options now are on a few of the bigger rivers as well as the spring creeks. The smaller freestone streams are cold and tough to fish at the moment.
Trout are now in the mode of a maintenance diet and their metabolism is directly tied to the water temperature which means it is slow. Most of the fish in our well entrenched in their winter runs. This time of year you need to be have laser focus on where you fish and target the deeper runs with slow to medium currents. Trout will no longer be found in the fast riffles or bustling pocket water that was so productive in the warmer months. The good news is that once you find some of these winter time honey holes they will be packed with trout. Fish densities in the best winter runs can be staggering with dozens upon dozens of trout packed together.
Nymphing is hands down the most effective technique in the cold weather months (although streamers and even dries can still be an option). The fly selection doesn’t have to be fancy but will very from fishery to fishery. On the bigger freestone rivers such as the Yellowstone, Gallatin and Madison it is nice to still fish something larger as the top fly such as a stonefly nymph, crayfish pattern or sculpin trailed by a smaller nymph. For small nymphs shoot for something in the 18-20 range. Patterns that produce include small baetis emergers, pheasant tails and midge larva. San Juan worms and eggs are also good patterns to try and if you are fishing a tailwater or spring creek a sow bug can produce (especially pink). The reality in the winter is where and how you fish is more important than the pattern. On spring creeks the big/small rule for nymphing can still apply but the “big fly” might be a size 14 sow bug trailed by a size 22 midge larva. Takes in the cold weather months are always very “soft”. The fact that trout are not moving much for flies along with the slow water that they are found in produces a very light reaction on a strike indicator. It is important to experiment with weighting to ensure flies are right on the bottom. Many of our guides also prefer a yarn indicator in the winter which makes it easier to see subtle ticks and changes of speed. If your indicator tilts, slows down, speeds up, or looks “funny” set the hook and ask questions later.
On a mild winter day you might be lucky enough to run into some rising trout feeding on midges. Even freestone streams like the Gallatin will produce some sporadic midge hatches, especially on mild days. If the hatch isn’t too strong dries that imitate single midges are more productive such as a palomino pattern. On tail waters like the Bighorn the midge hatches in the winter can be thick in the late morning and the insects will cluster together so many of the patterns such as the Griffiths gnat that imitate these “rafts” of insects can out produce single insect patterns.
Time of day is also important this time of year. Early mornings can be very tough fishing. The magic window in the winter is from around 1pm until 4:30 or so each day when water temperatures are peaking.
As we progress farther into the winter months it will pay to seek out waters that have some thermal protection from frigid air temperatures. Waters that are great producers even during cold snaps include the spring creeks, tail waters and certain freestone waters that have significant spring fed influences. Big freestone waters like the Yellowstone River will develop large ice shelves resulting in dangerous wading conditions.
Winter time water levels are always on the low side and there is a lot of definition to the water. The key to winter fishing is finding slower holding water and fishing in the afternoon when water temperatures are at their peak.
Midge hatches can be strong in some locations in the late morning and early afternoon when warmer mild weather settles in. Otherwise the fishing is a nymphing game.