Apparently they really like white clousers!
There were schools of 40-60 buffalo. Some tailing, some cruising, and some just chilling in the river. If you drift a white clouser through the school you'll get a strike or two and bump a few fish in the process. I've found the key to keeping them on is to put them on the reel as soon as possible, because if you have any slack they will spit the fly. These fish are freight trains and they will run faster than Usain Bolt, which makes for one amazing fight!