Ice-off is legendary 'way up by Yellowstone Park in the southeast corner of Idaho. We skunked out last weekend, (one hook-up, on an olive leech) These bigger-than-mosquito midges (diptera or chironomids) hung in clouds everywhere. Happy fish, they were slurping the emergers by the bushel. Locals call 'em Snow Flies because on sunny winter days, you'll see a few hatching near open water.