From what I have seen its easier to get a steelhead to bite when it is holding especially in the winter than when its moving. Most steelhead caught in the winter you catch when they are holding and that's why its best to fish a dropping and clearing river. The fish have been shooting up the river not looking at anything then slow down once the river starts to drop. You can catch them when they are moving but for the most part even fish in fast water are holding for one reason or another (behind a boulder in a slower seam). Why do you think that most people have a hard time catching steelhead when the rivers are blown out or rising? The fish are on a mission to get to the hatchery and one of the only ways to get them to bite when they are moving like that is to plunk.
There are obviously exceptions like the steelhead fishing on the Columbia but for the most part you catch holding steelhead.