I tipped the flies out onto the kitchen table then began to sift and separate, some of them so tiny I wondered if, on an overcast, windy day such as Wyoming often serves up this time of the year, Iâd be able to see well enough to thread slender tippet through the eye of the hook. The flies were purchased in preparation for an upcoming trip to Grey Reef, a section of the North Platte River near Casper. Renowned for its prolific population of large trout, Iâd fished Grey Reef once before, a decade and a half ago, and recall it as one of my most challenging, cold and unproductive days ever spent on a river. Iâm looking forward to the return.