The flats cover a vast expanse of area at the mouths of the Elk and Susquehanna River - both of which the stripers pour into to breed starting in early April. But before they go upriver and get busy, they need to feed. Enter the herring run. Both bass and herring cross paths on the flats, which average 4 to 10 feet deep. The result is a light-tackle anglers fantasy, where striper tails smack the surface and a popper fished on a light rod with a lot of backbone can produce strikes that will scare you so badly, you'll forget to set, forget to breathe, and then need to sit down for a while. These flats are one of a select few places where it's possible to stick a 50-plus-pound striper in four feet of water.