Disclaimer: The following report is compiled using artificial intelligence from current available data. Accuracy is not guarenteed. Always check local laws and regulations before fishing.

South Fork Snake River Fishing Report - 2025-11-10

River Description

• The South Fork Snake River in Swan Valley, Bonneville County, Idaho, is a premier freestone fishery renowned for its native cutthroat trout and scenic canyon stretches. Currently, flows are exceptionally low at 912 cfs near Irwin (-86% below average) and 1,390 cfs near Heise (-79% below average), with water temperatures holding steady at 48.9°F—ideal for cold-weather trout activity but signaling a technical fishery where fish are holding in deeper pools and seams. Mild weather patterns, including partly sunny skies and light SE winds (3-7 mph), combined with a waning gibbous moon (66% illumination) approaching last quarter on Nov. 12, suggest subdued insect activity and nocturnal feeding influences. This is a technical nymphing and streamer river with low, clear water favoring stealthy approaches; dry fly opportunities may be limited to midges, but wading access is excellent due to reduced volumes.

3-Day Forecast

• Monday (Nov. 10): Partly sunny with highs near 57°F and lows around 30°F; light winds persist, improving visibility for sight fishing and nymphing while stable conditions could trigger subtle midge hatches in afternoons.
• Tuesday (Nov. 11): Similar partly sunny skies with highs in the mid-50s and lows near 28°F; minimal precipitation risk enhances dry fly potential if temperatures rise slightly, though cooler evenings may slow surface action.
• Wednesday (Nov. 12): Clearing trends with highs around 55°F and lows in the upper 20s; light winds continue, but the last quarter moon phase may concentrate fish feeding at dawn/dusk—overall, favorable for consistent subsurface success without major disruptions. (Note: Extended forecast data limited; based on current trends from NWS.)

Fishing Outlook

• Fair: Low flows concentrate trout in predictable lies but make them wary in ultra-clear water, reducing hookups for less precise presentations; cool temps (48.9°F) limit aggressive rises, favoring nymphs over dries. Moderate weather and waning lunar illumination support steady but not explosive action, with yesterday's windy conditions (up to 67.6 mph) giving way to calmer days that boost angler comfort and fish visibility—best for patient anglers targeting pools rather than riffles.

Recommendations

• Flies & Techniques: Focus on subsurface tactics for cutthroat trout—try Zebra Midges (sizes 18-22, black or olive) under indicators for low-light nymphing in seams; Egg Patterns like glo-bugs (size 10-12, peach or pink) to mimic spawning cues in tailouts; and Woolly Buggers (size 8-10, olive/black) swung on sinking lines for aggressive takes from deeper holds. Dead-drift nymphs in the 912 cfs flows near Irwin for best results.
• Best Times & Tips: Prime windows are dawn (moonset influence) and late afternoon (2-5 PM) when light winds aid casting; avoid mid-day glare on clear water. Wading is safer with low gage heights (4.46 ft at Irwin), but watch for icy banks and hypothermia risks in 30°F lows—wear layers and studded boots. Target undercut banks and confluences like the Teton River input (148 cfs, -28% average) for holding fish.
• Gear Notes: 5-6 wt rods for accurate short casts in technical water; pair with 4X-5X fluorocarbon tippet to combat spookiness; floating lines suffice, but add a sink-tip for streamers in 48.9°F depths.

(Word count: 512)