Kolob report and help needed

[frogfish]

I happend to be in So. Utah on Monday. and fished Kolob at dusk. There was a hatch that the fish were going nuts on. A barrage of feeding trout for an hour. I'm embarrassed to say I landed nothing. The insects hatching looked like mosquitos but they left us alone so I wonder if they were something else. The trout looked like they were feeding right below the surface on emergers but there were a lot of bugs on top. (I saw a lot of fins and not too many mouths.) I tried a giffiths gnat (this was the closest match to what was going on), a pmd, a green wooley bugger, and a few lures. The lures were untouched. I had a few hits on the flies but I couldn't hook anything. Any ideas on what pattern would work at these times? Given the amount of surface action I should have had a hit every cast if the pattern and/or presentation was right. I am going back next week and hope to have a better report with your ideas!
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