My favorite hatch is the giant stonefly hatch on the colorado river. You have thousands of large, clumsy flying, bright orange stoneflies the size of your finger covering the willows. Flip a rock near the banks and there are crazy numbers if nymphs under every one. I flipped a rock last year and found a wad of stonefly nymphs the size of a baseball, literally.
My second favorite is the august/september trico hatch, also on my home river the upper colorado. These tiny mayflies, often mistaken for midges, hatch in the morning covering the river in tiny duns. A few hours later the mating swarm starts up creating a cloud of tricos that looks like smoke from downstream at times. Then, comes the spinner fall. All the adults that have just mated fall to the water exhausted and die, what a way to go. From there its game on fishing double dry setups to sipping trout. I usually lead with a #20 for visibility and drop a #24 spinner for the picky fish. The trico hatch is technical fishing at its finest.
