The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
This video shows just how blizzard-like the Hexagenia limbata hatch can be. I only wish my digital camera had had respectable video capability back in 2005.
The Namekagon is not known as a Hex hatch river, for good reason: the hatch is extremely rare and localized, and there are often few if any trout where the Hexes are. During this trip I caught nothing and heard no risers, but it was still a memorable night out in the middle of nowhere.