I am kneeling in the silt at the edge of the Madison River, halfway down the Madison Valley north of Yellowstone Park. The afternoon light is dropping, and the clouds hover just above the asphalt on the highway across the river. Snow is coming down hard, skidding upstream as if it were falling in horizontal threads. I am casting a trout fly no bigger than a snowflake, letting the wind carry it above the fish - rainbows and browns - that are feeding in the shallows in front of me.
