Yup its true those big nasty Pteronarcys are flying around on the Upper Colorado making anglers go crazy. This hatch always marks the beginning of run off and I can only remember one season when water clarity was worth a damn during the famed Salmonfly Hatch. Every year I am one of the anglers driving up to Pump House to see what all the fuss is about, and each year I get similar results, high water, big bugs and few trout. Maybe I am just a poor angler, I am not arguing that, or maybe it is just that there is so much food in the water that these trout are gorging.
Of course when you hear Salmonfly hatch you think of fish ferociously thrashing the surface eating adult flies. And while that does happen the reality of the situation is that you are probably not going to be crushing fish on top. In fact you will probably have a bit more success just under the surface. But, if you are nuts about this hatch and want to catch these picky trout on dries here is a tiny bit of advice.
First there really is no need to rush to the river, in my experience the Salmonfly Hatch on the Colorado River tends to come off later in the day. Believe me you cannot miss it. All of a sudden you will see what look like small bats flying up the river. Occasionally you will have one land on your neck and a freak out will happen. Don’t worry they don’t bite.
Be careful. Like mentioned above the water tends to be very high so whether you are floating or wading be more cautious than usual. The water is cold and fast.
Look for overhanging trees and bushes. Salmonflies will land in these areas and start to mate. It is not uncommon to see clumps of bugs locked together in these areas. Fish hard under these trees and bushes, naturally a Salmonfly will fall out of the overhanging shrubbery and become an easy target for picky trout. This has been the most successful technique for me.
Bring a couple different nymph and dry patterns. I prefer a foam body dry but they do get saturated easily. For nymphs it is tough to beat a Black Pats Rubber Leg. These stonefly patterns are so simple yet very very effective. If the fish are not eating on top try dropping a Pats off your dry and see what happens. More times than not the trout are feeding just under the surface as the Salmonflies emerge.
The current flow on the upper Colorado is just over 4500 cfs. Thats 4500 basket balls coming down stream every second. Think about that for a minute. Have fun up there and be careful.