St. Vrain Creek (Lyons area)
St. Vrain Creek (Lyons Area) — Fishing Report for April 26, 2026
Quick Stats
Flow: 9 CFS | Trend: Falling sharply | Fishability: Fair | Weather: Showers and thunderstorms likely, high 54°F
The Bite
This has been a dry water year across the South Platte basin — snowpack is sitting at roughly 16% of normal, and the St. Vrain is showing it. At 9 CFS and falling, flows are well below the 25-80 CFS range you'd typically expect for late April. That's not necessarily a dealbreaker, but it changes the game: the water is low and likely clear, which means fish can see everything — your fly, your leader, and you. Stealth and presentation matter more than usual today.
The silver lining is that post-winter fish are still hungry, and low, clear conditions concentrate them in predictable lies — deeper slots, undercut banks, and the heads of pools where a trickle of current delivers food. Afternoon thunderstorms are in the forecast, so the window for comfortable fishing may be compressed. If you can get on the water mid-morning before storms build, that's your best opportunity. Any extended overcast period between cells could trigger a brief BWO emergence — watch the slower tailouts and eddies for rising fish.
Don't expect the aggressive spring feeding surge the seasonal outlook describes — the combination of very low flows and unsettled weather will keep fish cautious. That said, a careful angler working the right structure with small, precise presentations should find willing fish.
What to Fish
- RS2 (gray) #20-22 — Primary nymph for low, clear conditions. Dead-drift through deeper slots with a natural, drag-free presentation.
- Juju Baetis #20-22 — Excellent subsurface BWO imitation; fish it as a dropper 14-18" below a small beadhead anchor.
- Pheasant Tail #16-18 — Reliable searching nymph in the runs and riffles; go unweighted or lightly weighted to match the shallow flows.
- Don King #22-24 — Midge larva for slower, deeper pockets where fish are holding tight to the bottom.
- Parachute Adams #18-20 — If overcast breaks between storms produce surface activity, this is your dry fly; fish it in the slower tailouts.
- Elk Hair Caddis (olive) #14-16 — Worth having ready as early Mother's Day Caddis scouts may be present on warmer afternoon windows.
Tactics & Rigging
Given the low, clear water, go light on tippet — 6X fluorocarbon is a reasonable starting point, and dropping to 7X for the smaller patterns is worth considering if fish are spooky. A double-nymph setup works well here: use a lightly weighted Pheasant Tail on point as your anchor, with an RS2 or Juju Baetis trailed 14" above it on a tag off the tippet. Keep your indicator small or ditch it entirely in favor of a tight-line or high-stick approach in the shallower runs — a large indicator will spook fish in thin water.
Focus your casts on the deepest available water: undercut banks, the head of pools where current slows, and any seam where fast water meets slack. Approach from downstream and keep a low profile. If you catch a BWO emergence window between storm cells, switch to a Parachute Adams with a size 22 RS2 dropped 16" below as a dry-dropper — the dry acts as your indicator and the emerger does the work just under the surface film.
Access & Logistics
Thunderstorms are likely through the afternoon — lightning risk in the canyon is real. Keep an eye on the sky and have an exit plan. The Lyons area access points are straightforward, but trail surfaces may be slick after morning showers. Verify current regulations with CPW before fishing, as rules can change.
Stop by St. Vrain Anglers for flies, local intel, and to support the shops that keep these fisheries healthy.
Looking Ahead
Monday brings more showers and thunderstorms with a high of 59°F, so don't expect a dramatic improvement in conditions early in the week. With snowpack as thin as it is this year, a significant flow bump from spring runoff is unlikely — the St. Vrain may stay low and fishable well into May, which could actually extend the dry-fly season if water temps cooperate.