Last updated: July 25, 2023
Fly fishing with dry flies for big trout is one of my favorite activities. When the Green Drakes hatch the rivers are alive with big fish actively chasing and eating big bugs.
Watching big browns break the surface to inhale a dry fly is an activity that is relished by most fly fishermen. You may have a couple of eats during any given day on the river, but that textbook take by a big brown is what you play out in your mind’s eye in slow motion. But, when the stars align and the weather is perfect for a hatch, the water temperature is cooperating, and the fish gods are in a good mood, you may experience a full blown hatch.
When Does the Hatch Happen?
One of the most prolific in the state of Utah is the Green Drake hatch which occurs mid-to-late-June and often continues past the 4th of July. When these big mayflies are hatching the trout take notice and are more easily caught on dry flies in big numbers. While it is no secret that this is a great hatch to fish, I am sure to get some backlash for even writing about it.
Drunella grandis, D. doddsi, D. spinefera are the scientific names of the Green Drake. It is a crawling mayfly that is large and strong, spending most of its life in fast riffles and runs. It is not often dislodged from its nymphal home and so it is not fished as a nymph very often. Most anglers wait until the Drakes mature and begin to migrate into slower-moving waters, the heads or tails of pools and areas of more moderate flows. This migration is the precursor to the hatch.
Often when the first adults begin to break free of the surface, fish will be feeding on the nymphs and the emergers. At times it may take a day or two for the trout to really start feeding well on the dry fly. Then the magic happens. Big browns begin to look up for food and lose the wariness of the past six months. Gone are the days of small flies. Nymph rigs are forgotten and 4x tippet smiles at you as you tie on big dry flies. Runs you have been fishing the last few months have more fish rising in them than you can remember seeing.
How to Catch Big Browns During the Hatch
Green Drakes hatch in large numbers and the conditions need to be right. I have had times on the river when the hatch was really turning on and a thunderstorm came over the mountain and put a quick end to it. Droughts can push the hatch early while excessively cold and rainy spring weather can push it back a few weeks.
Word gets out quickly when the hatch is on and the local rivers, with good populations of Drakes, become busy. Don’t be afraid of the increased anglers on the water. You do not need as much water as before. Just look for noses punching through the surface and big flies acting as struggling helicopters in the surface film and you will catch fish.
A great strategy to picking off a lot of risers is to start at the tail of a pool and wait for rising fish. A lot of false casting and wading will spook the trout. Be patient and pick off fish slowly as you move through the run. Green Drakes have a dun wing upon hatching and then molt into the mature adult with clear wings known as spinners. The females return to the water to lay eggs, but this is typically after sunset. Size 10 and 12 dry flies are my favorite sizes for the hatch. Green Drake specific flies in standard, parachute, and cripple patterns all produce, as well as green-colored flies of other varieties such as stimulators. One of my go-to setups is a double dry rig with a foam or hair wing Drake followed by a cripple.
It Only Happens Once a Year
While there is no way to know the exact time or day of the hatch, it usually occurs around the summer solstice each year. The hatch travels upstream and can move a mile a day on the Middle Provo River. If you hear the Green Drakes are hatching, get out on the river and enjoy the fun. It will not last long, so burn some vacation time and throw some big bugs at big browns.
Travis Jay Vernon, Fly Fishing Guide & Sales Associate