Fly Fishing Report for the Treasure Valley 12/4/2024

Hello Winter!

Now is the time to slow down and refine your cold-weather fishing techniques. Some of the best walk-and-wade fishing on the Boise River happens during the off-season. While fair-weather fly fishers pack up their gear and wait for warmer days, those who know fish feed year-round adjust their approach for the winter.

To succeed in winter, a few key adjustments are necessary. Start by downsizing both your tippet and flies. Then, ensure your rig is perfectly tuned to the water you’re fishing. If you’re not deep enough, go deeper! Proper depth and split shot placement are crucial. In contrast to summer, where morning feeding windows align with cooler temperatures or specific hatches like mayflies, caddis, or summer stones, winter fishing is more about timing and location.

Forget about early-morning fishing unless that’s your only window. A slight increase in water temperature is often enough to trigger a feeding frenzy, meaning afternoons will be your best bet for success.

Indicator or Euro nymphing will always be the most productive in winter, but don’t overlook streamers. Whether large articulated patterns or smaller single-hook variations, streamers can be just as effective. And if you’re lucky enough to spot midge sippers in the foam, dry fly fishing can be challenging but incredibly rewarding. Not many fly fishers have the patience to target risers in the winter months—but those who do, often find the experience unforgettable.

Boise River Fishing Report – In Town

With flows around 300 cfs, now is the perfect time to access the entire stretch of the Boise River, from Highway 21 down to Middleton. The greenbelt, public parks, and bridge crossings provide excellent access. The key is to pick a section of river and thoroughly cover it—there isn’t one section that consistently fishes better than another; it’s all about timing.

Whether you’re using an indicator setup or Euro nymphing, these techniques will generally outperform streamer fishing. However, if you prefer quality over quantity, streamer fishing is a great way to target larger resident browns. While a faster retrieve works in warmer months, winter requires slowing things down. Try slow stripping, jigging, or swinging flies for better hook-ups. You may also encounter a late afternoon midge hatch—look for foam lines and slower seams, as these are prime feeding zones.

Steelhead have been stocked at the usual five locations around town: Glenwood, Americana, Boise State, Park Center, and Barber Park. If you’re targeting steelhead, this is a great opportunity! After the initial stocking, crowds thin out and the fish start to spread throughout the river. Effective setups include egg-sucking leeches, egg patterns, and larger nymphs. Use the same nymph rig you’d use for trout, but with heavier tippet (10-12 lb fluorocarbon) and a 6 or 7 weight rod. Just remember, if you’re targeting steelhead, a steelhead tag is required. They’re delicious on the smoker!

Recommended Boise River Flies: FB Pheasant Tail (#16-20), Copper John (#14-20), Higa’s SOS (#16-20), Red Neck (#14-18), SOB Czech Ginger (#14-18), Sheila Sculpin #4, Galloups Boogieman #2, Sculpzilla #2 (Zebra Midge (#18-22).

South Fork Boise Fishing Report – Tailwater

After the heavy fall fishing traffic subsides, the crowds thin out, making the South Fork an ideal day-trip destination. Before heading out, keep a few things in mind: ensure your vehicle’s tires have good traction, consider bringing chains, and always check road and weather conditions beforehand.

For those who don’t have the chance to float during the summer season, winter fishing can be exceptional—just be prepared for the cold! Midge activity is often a daily occurrence, and larger fish can be found sipping in the foam lines. When you see rises, they may appear to be smaller fish, but don’t be fooled—larger fish can sip just as discreetly. To target these fish, small midge emergers and adults in sizes 20–24 are essential. Presentation and stealth are crucial, so be sure to use longer leaders (5x or 6x). Positioning yourself for an optimal cast and avoiding micro drag will be key to success.

As usual, indicator fishing with stoneflies and smaller midge or baetis droppers is a reliable strategy. If you’re euro nymphing, use an oversized bead jig head nymph as your anchor, with a small midge or baetis (#18–22) as the tag fly. Jig head stonefly nymphs or leeches also work well as anchor flies.

In winter, we typically focus on fishing the slower seams outside of faster riffles as compared to summer. With the South Fork tailwater, remember that the water temperatures below the dam are stable all winter long, ranging from 46–48°F, which is typically warmer than the daytime air temperatures. Don’t overlook the faster water, as fish are still holding or moving in to feed.

If you’re fishing streamers, the same techniques apply: slow swinging, jigging, and stripping can all be effective. Bull trout are present in the system and can provide an exciting catch. Be sure to keep them wet, quickly remove the hook, and release them promptly after a memorable photo. Color combinations that tend to work best include olive, white, and natural combos.

Recommended South Fork Boise Flies: Pat’s Rubber Legs (#6-12), Split case BWO (#16-20), Mercer’s Jigster Baetis (#16-18), Quill Jig (#14-16), RS2 (#18-22), Captive Dun BWO (#18-22), BWO Comparadun (#18-22), Sheila Sculpin (#4), Sculpzilla (#4)