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.

River Description

• The South Fork Snake River in Swan Valley flows clear and steady through Bonneville County's scenic canyons on this mid-January day, with below-average flows at 912 cfs near Irwin and 1380 cfs near Heise creating technical wading opportunities in a classic freestone river.
• Water temps hover at 48.9°F, keeping fish sluggish but active in deeper pools, while high humidity and light ESE winds limit surface disturbance for precise presentations.
• Lunar conditions feature a waning crescent moon at 40% illumination, with last quarter phase yesterday promoting subtle feeding rhythms best during low-light periods; overall, this setup favors technical nymphing over dry flies in the cold, with moderate fishing potential for trophy cutthroat and rainbows holding in slower seams.

3-Day Forecast

• Day 1 (Jan 12): Highs reaching 42°F under partly cloudy skies with light winds (5-10 mph), improving visibility for sight-nymphing while steady cold fronts keep hatches minimal but boost subsurface activity in stable water.
• Day 2 (Jan 13): Warming to 45°F with clearing conditions and calmer winds, potentially triggering sparse midges on warmer afternoons and enhancing streamer retrieves as fish metabolism ticks up slightly.
• Day 3 (Jan 14): Highs near 40°F with possible light snow flurries and increasing humidity, which could murk up edges but concentrate fish in main channels for consistent nymphing success despite reduced surface action.

Fishing Outlook

• Fair conditions overall, as cold water temps and low flows demand precise, slow presentations to entice lethargic trout, but stable gage heights (4.46 ft near Irwin, 1.61 ft near Heise) minimize flood risks and allow access to prime winter lies.
• High humidity (88%) and yesterday's wind gusts up to 50 mph have transitioned to calmer air today, reducing drift boat challenges while the waning moon supports better bites around dawn and dusk when illumination dips.
• Combined factors limit explosive hatches but reward patience with nymphs in riffles, yielding solid hookups for 16-20 inch cutthroats if anglers target deeper runs amid the Teton River's tributary influence keeping flows consistent.

Recommendations

• Flies & Techniques: Go with small nymphs like #14-16 Pheasant Tail or Hare's Ear in natural tones for dead-drift indicator setups in 3-5 ft depths; add #8-10 Woolly Buggers in black or olive for swinging streamers through undercut banks to provoke aggressive strikes from winter rainbows.
• For sparse midge activity, try #18-20 Griffith's Gnat dry flies during midday calm, focusing on soft hackle droppers below indicators to mimic emerging larvae.
• Best Times & Tips: Target dawn (6-8 AM) and dusk (4-6 PM) windows when low light and moon phase align for peak feeding; wade cautiously in low flows to avoid slick rocks, and watch for hypothermia risks with today's 39°F high—layer up and fish from boats if winds pick up.
• Pack thermos for breaks, as high humidity can chill you fast post-wade.
• Gear Notes: A 4-5 wt rod with a 9-10 ft leader excels for delicate nymph presentations in clear water; use 4X fluorocarbon tippet to handle subtle takes, and opt for mid-action reels to manage occasional larger fish without spooking the school.