I'm convinced Salmon are affected by pressure swings, but dont apply the same thought to Steelhead. I think many who have been fishing for steelhead much longer than I would agree they can be caught on the sunniest of days, in the nastiest of weather, and most everything in between.
My layman's summary of what I've read so far is that fish will become more active just before a drop in barometric pressure, and less active the longer that the low pressure system is around. The last two trips to the river have been tough.
I actually like low pressure in the winter , when the river gets low and cold. I seem to do best fishing under those conditions because it concentrates the fish and the methods I typically employ get them to bite.
If you are referring to fishing at Reiter on the Sky during those last few trips.... There were a ton of fish caught on NYE morning when the river was dropping from ~11-10k. I hooked four and saw probably 40 fish on the bank. The next day I went up with three other members here and we fish from there down to Proctor and only hooked two, landed two for the group. Out of the the rest of the army of casters I saw roughly six fish for 40-50 people...
That's fishing....