I've fished Pass lake about 10 times since March and have had only limited success. Indeed, Skagit Valley Anglers in Mt. Vernon says that it's been slow all spring.
However, I have caught fish there, and all were caught on the West side of the lake using large dark chironomids (12 and 14) suspended 18" under an indicator. Cast to within a foot of shore.
I've tried wooly buggers with no luck - this continues to be surprising because WBs are historically a productive fly. The last time I was out (last Sunday) I ran across an emergence of PMDs, but couldn't buy a fish.
I was out the past two friday nites in a row and had some good success on black buggers (heavily weighted) close to dark. i am fishing a floating line with about a thirteen foot leader, difficult to cast but productive lately. drag it around slowly and hold on tight, i managed one fish that was eighteen inches and two others that were sixteen. i also hit a really nice sixteen incher on an adams right before dark. i know, i know, it was like cheating tricking him like that but i was getting desperate, all of those rises you know. good luck. email in private if you want more details i guess.