By Steve Smith
Rivers Wild Flies

One of the great summer hatches of the west is the Pale Morning Dun. When the weather starts to warm and the rivers return to their normal flows, the PMD hatch is one of the most reliable hatches all summer long. These pale-yellow mayflies will emerge not just in the morning as the name implies but throughout the day. The hatch usually begins in June and can last into September.
I’ve enjoyed PMD hatches on my home waters of the Blacksmith Fork and Logan rivers in Northern Utah, along with fantastic fishing on the South Fork of the Snake and the Henry’s Fork in Eastern Idaho. The South Fork especially stands out in my mind where beautiful Cutthroat trout stack into shallow riffles along the gravel bars. When the hatch is on you’ll see noses and tails swirling in the choppy water. I’ve have great days on the South Fork and I’ve gotten my butt kicked. These fish see their fair share of PMD patterns thrown at them so they get educated quickly. That’s why I make sure my fly box is stocked with a variety of patterns to match the PMD hatch. I like Pheasant Tails for the nymph stage, a RS2 PMD for the emerger stage, and a Thorax Dun for the adult stage. I also carry a few Rusty Spinners for the spinner stage. The Thorax PMD is my favorite pattern. I use it as my main fly and may trail a Pheasant tail or an RS2 behind.
The key features that set the Thorax style PMD apart from the traditional PMD is the straight upright wing and spaced hackle. The wing is tied with Turkey flats which can be frustrating but it gives the fly a unique profile similar to the natural. Poly yarn is a good substitute for the wing. Traditional style PMDs are tied with tight wraps of hackle giving the fly a “fluffy” appearance. This is nice in fast moving water where flotation is important but may be a little overdressed in slower moving riffles where PMDs are more likely to hatch. The Thorax style hackle is evenly spaced through the front half of the hook and is clipped on the bottom. This allows the fly to sit lower in the water creating a more defined body outline. Sportsman’s Warehouse has beautifully tied Thorax PMD’s at ridiculously low prices. So stop in and grab a couple because there’s a good chance you’ll see PMDs on the river this summer.