Winter Fly Fishing on the Blue River: Tactics for Tailwater Success

The Blue River below Green Mountain Reservoir is a classic Colorado tailwater known for its clear flows, consistent temperatures, and thriving trout population.

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Winter on the Blue River below Green Mountain Reservoir is a mix of stunning solitude and technical fishing. With low flows and gin-clear water, the trout here aren’t handing out easy eats, but if you dial in your presentation, you can hook into some truly impressive fish. Browns and rainbows are stacked in the deeper runs, feeding lightly on midges and Baetis nymphs, while the occasional streamer bite can entice a larger, more aggressive fish.

Access can be tricky in winter, especially with snow and ice on the trails, but for those willing to put in the effort, the payoff is there. Long leaders, 6X tippet, and tiny flies are the name of the game. If you’re looking for big-water nymphing, this is your spot. Just be ready for some cold mornings and the occasional frozen guide.

Conditions Summary

• Flow Rate: 50-75 CFS (low, but steady)
• Water Temperature: 34-38°F
• Clarity: Crystal clear
• Best Times: Late morning to mid-afternoon
• Star Rating: ⭐⭐ (2/5 – Technical but rewarding if fished correctly)

River Flow Chart

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Blue River Hatch Chart

Top 3 Flies for the Week

• Dry Fly: Griffith’s Gnat (#20-22) – If you get lucky with rising fish in slow tailouts.
• Nymph: Jujubee Midge (#20-24) – The go-to pattern for low and slow winter drifts.
• Streamer: Pine Squirrel Leech (#10-12) – Slowly dead-drifted or lightly twitched.

Tips for Fly Fishing the Blue River Below Green Mountain

Seasonal Tip

Fish are hunkered down and feeding selectively—adjust your depth frequently and stay subtle in your presentations.

Dry Fly

Minimal surface activity, but small midges in slow pools can bring occasional risers.

Nymphing

The most productive technique right now—midges, Baetis, and scuds on light tippet with a long, natural drift will put fish in the net.

Streamer Fishing

With low flows, trout won’t chase much, but a dead-drifted leech or sculpin can still pick up a bigger brown.

Access Points

Green Mountain Canyon Trailhead

• Description: The main access point below the dam, offering deep pools and runs.
• Why Fish Here: Year-round fishery with solid holding water.
• Locals’ Rating: ⭐⭐⭐⭐⭐

Blue River State Wildlife Area

• Description: Good bank access with some productive riffles and pocket water.
• Why Fish Here: Less pressured than the immediate tailwater below the dam.
• Locals’ Rating: ⭐⭐⭐⭐

Lower Blue River (Further Downstream)

• Description: Tougher access in winter but worth it for adventurous anglers.
• Why Fish Here: Bigger fish, fewer people.
• Locals’ Rating: ⭐⭐⭐⭐

Local Regulations and Notes on Landowner Rights

• Artificial flies and lures only—no bait fishing allowed.
• Catch-and-release recommended to maintain the wild trout population.
• Private property markers: Look for fence lines, posted signs, and ranch property boundaries along the lower sections.
• Winter safety tip: Watch for icy riverbanks and deep snowdrifts on access trails.

If you’re up for a challenge and want to escape the crowds, the Blue River below Green Mountain Reservoir offers beautiful scenery, technical fishing, and the potential for big trout—just be prepared to work for them.