Winter fly fishing in the Big Sky and Bozeman area on the Gallatin River is as consistent as any winter fishery as any in the area. Additionally, the flows on the Gallatin River in winter are low, which means the fish are concentrated in the deeper runs, pockets, and holes. Because the Gallatin River is low you will need to cover a lot of water when you fish. If you fish a deep run or hole and catch a few fish, consider moving up to the next run or hole. With the low and clear flows on the Gallatin River right now fishing subsurface is the best way to get into fish at the moment.
The Gallatin is low and gin clear right now. The fish are starting to stack up in the slower slicks and runs with some depth and slow to medium speed currents. Nymphing has been most productive most of the day with smaller baetis patterns offering the most productivity. Egg patterns are also producing in wake of the whitefish spawn and before the brown trout spawn. On mild days we have observed some decent midge hatches that are bring a few trout to the surface so bring some small midge dries just in case.
Choose tandem nymph rigs with flies in the size 18-22 range. See the list of flies below for the best choices. With the low, clear water for success you will need to drop down in tippet sizes so you are getting a better drift. Many anglers are going to 9 foot 5X leaders with 5X fluorocarbon for their tippets. Trout are being found in the 5-6 feet deep medium fast runs during most of the day. Be sure to read one of our latest blog posts on choosing the best leader for fishing.
The Gallatin is low and clear and is fishing well for most of its length. The ice shelves are still at bay on the lower water and the river in the valley is still fishing well. Mild days are even producing some risers over the midge hatch. Nymphing is the best bet and it pays to skip a lot of water and jump from one deep run to another. Look for steady currents that aren’t too strong but still enough to bring food to trout. Slow water that is 3-6 feet deep and located just below a riffle is always a good bet. Nymphing stone fly nymphs trailed by a baetis nymph or midge larva is a good bet but egg patterns and worms are also good flies to try.
The Month Ahead:
The Gallatin River near Big Sky and Bozeman fishes well all winter. Don’t mess with the fast water as the fish will have moved into the slower and deeper runs. There are several springs near the Big Sky junction that keep the upper canyon waters ice free and this is a great place to fish in the colder months. During cold snaps the valley waters develop slush and big ice shelves. If you find icy conditions just keep driving upstream towards Big Sky. Upstream of Big Sky ice is also a problem so the 15-20 miles from Big Sky down is the best on the coldest days. Nymphing smaller patterns and eggs is the big producer.
Flies for the Gallatin River for the Next Month:
Lightening Bugs in sizes 16-18
Juju baetis in black or olive in sizes 18-20
Firebhead or hotbead SJ worms in sizes 12-16
Sawyer PTs in sizes 18-22
Zebra Midges in black, red, or olive in sizes 18-22
Pheasant Tails in sizes 16-20
Little Spankers in sizes 18-20
Pat's Rubberlegs in sizes 12-14
Long Term Fishing Forecast:
The info above will be the forecast for most of the winter. Once March hits, the Gallatin River will produce a little more variety as the baeits mayflies become active again.