abe,
Try fishing the hole just below rock creek ( the fly only deadline) under the bridge there is a deep slot. Ive fished there in the past. Cross the bridge and fish the top end of the hole. Try drift fishing it with lots of weight to slow your offering. I like to use a bigger bait when the water is high and cold.
The fishing will pick up when the water warms up a bit. Spring chinook are most active when the water approaches 54 degrees.