Flavs are making their significant appearance on the Henry’s Fork around Last Chance where they are famed for bringing up big rainbows. But do not think of flavs as only a “big stream” mayfly. They also live in appropriate (quality moving water with gravelly substrate) small streams. I have fished them on eastern Idaho’s Salt River tributaries this time of year. Eventually flavs will be emerging from Bear, Big Elk, McCoy, and Palisades creeks, the Big Lost River and other local waters. Yesterday they were coming off from Birch Creek in enough numbers that every trout there seemed to be rising.