Fly Fishing Madison River - Bear Trap Canyon

Overview

Bear Trap Canyon is the Madison River reach below the Madison Dam powerhouse at Ennis Lake, running through the Bear Trap unit of the Lee Metcalf Wilderness to Warm Springs on Highway 84. Canyon walls confine the river, and boulders break the current into buckets, seams and back eddies.

Brown trout, rainbow trout and mountain whitefish share this water. Reading the pockets is central to fishing it: small boulders create compact holding water, while larger rocks form deeper slots that call for a different drift and weight.

Reading the canyon

The canyon reshapes the river completely. Below the powerhouse it is compressed between canyon walls and dropped over house-sized rock, and the flow breaks into a sequence of buckets, seams and back eddies. Small boulders create compact pockets; larger ones create slots deep enough to call for a sink-tip and a heavy sculpin pattern. Sight-fishing gives way to reading the water.

Every large rock creates several places to examine: a cushion in front, a seam down each side and a softer pocket behind. Fish can use all three, and their positions change with the current. The useful drift is short, so cast close, keep the rod high and lead the fly through the slot rather than mending endlessly. Work each piece of water deliberately before moving to the next rock.

Weighted rigs and streamers

Tactics in Bear Trap reward simplicity and weight. A 9-foot 5- or 6-weight handles nymph rigs; a 7-weight is an option for articulated streamers in the deep slots. A short, stout leader keeps a two-nymph rig turning over in the wind that funnels through the canyon. Adjust the split shot to reach the depth of the bucket you are fishing, rather than drifting above it.

Girdle bugs, Pat's rubber legs and other big black stonefly nymphs can anchor a rig, trailed by a small dark pupa or a beadhead mayfly nymph. When the water is off-color or the light is low, try a sculpin or crayfish pattern along the boulder edges. Change the angle and depth of the presentation before assuming the pocket has nothing to offer.

Seasonal patterns

Midges are a winter and early-spring option, fished small and deep in slower slots. Blue-winged olives are a focus on grey, drizzly spring days and again in fall. The Mother's Day caddis and early-summer salmonflies give another reason to watch the surface as well as the pockets: big black nymphs before the salmonfly hatch and foam dries during it are familiar approaches here.

Pale morning duns follow through summer, while golden stones and yellow sallies are patterns to consider at riffled edges. Terrestrials offer another approach along the grassy canyon margins. Match what you see on the water rather than expecting the same activity throughout the reach.

The canyon is rocky and exposed, and Ennis Lake releases can change the depth and current around its boulders.

Access

Use the marked parking spaces at Warm Springs day-use area off Highway 84 for fishing access at the downstream end of Bear Trap Canyon.