Surface flies work this time of year-try a #18-22 Parachute Adams for both midges and Baetis but more importantly, hang a #20-22 WD40, Yong Special, or slim Pheasant Tail off the bend of the dry-fly hook. Most fish take the nymph just under the surface. Think dry-and-dropper for most Poudre and Big T hatches and you'll win big.

Prior to runoff from the beginning of March through April, you can also find hatches of Western March Browns. During peak runoff, from the end of May through June, the angling becomes difficult and wading nearly impossible. However, the tremendous water flow and warming trend triggers a multitude of hatches. Salmonflies (Pteronarcys californica), Pale Morning Duns, Green Drakes, and several species of caddis explode onto the scene and then taper off toward August.

Elk-hair Caddis and #12-16 olive or yellow Stimulators are great attractor patterns. Grannom caddis-the ones that build oblong rectangular homes from wood particles on the river bottom-produce the thickest hatches on the Big T.

Ben Walsmith, a guide in the area says, "Some nights the caddis hatch is so thick, you can't breath through your mouth."

A local caddis hatch tactic is to wet an Elk-hair Caddis and drift it subsurface through a pod of active feeders. Most of the time, Big T trout eat adult caddis right under the surface just as they emerge. Until they learn this technique, many anglers go home frustrated with floatant-covered fingers.

Ants and beetles find their way down to the Big Thompson by the end of June and stick around until the end of September. August provides a dependable Red Quill hatch as well as good numbers of Yellow Sallys. Anglers get another shot at Blue-winged Olives in September and October.

A 10-mile catch-and-release section from the dam in Estes Park to Waltonia Bridge is the most popular stretch for fly fishers. Catch-and-release signs posted along Highway 34 identify more than 40 public parking areas in this stretch. Every pull-off has healthy numbers of fish and a mix of flats, pockets, and bend pools. The steeper-sloped canyon water contains exceptional nymphing runs, but fish also rise for dry flys like a CDC emerger or X-Caddis.

Canyon Tackle

The Big Thompson special-regulation water is not stocked and is one of the few places in the state where whirling disease seems to have little effect on the trout population. Wild rainbow trout (above) are the river's main attraction.

A 4-weight rod is perfect for both the Poudre and the Big T. It has enough backbone to haul in any fish you might catch and is light enough to make the day enjoyable. You rarely make long casts here or use overly large flies, and although Northern Colorado is known to be windy, these canyon streams are relatively protected.

Breathable waders with studded-felt boots are the most comfortable for a day on either of these rivers during the summer months. The Big T especially is known for its rocky terrain. The 1976 flood that killed 139 people and stands as Colorado's single worst natural disaster displaced numerous large boulders. Some are still perched in precarious positions but most are just obstacles. It's easy to twist an ankle just negotiating along the river bank and wading can be difficult. Bring a wading staff. It can be hot and dry in the summer months so also bring plenty of water. A 9-foot leader tapered down to 4X tippet and spools of 4X, 5X, and 6X tippet will see you through most situations, although 3X is sometimes helpful for large Stimulators and grasshopper imitations, or those times when you feel the need to throw a Woolly Bugger.

Most of the fishing is dry-and-dropper rigs but when nothing is hatching, the fish can be unwilling to move up the water column for a fly. A deep- nymphing rig sometimes saves the day, so don't forget to bring strike indicators and split-shot.