Hi Matt: In my book a slot is formed when water passes between to major obstructions, most commonly between two submerged boulders. Because more water is being forced through the gap current speed is accelerated and some turbulence created. The water excavates the bottom below the obstructions and deeper water moves more slowly . In surface appearance ;wheras the general surface is broken by small waves in good steelhead currents the surface of the slot is smoother and darker . Steelhead like to lie in water that has equal speed on both sides of their bodies thus keeping them in balance . Usually they will lie just below the start of the slot where the water starts to slow again after being speeded up in the slot.
This is my understanding of the situation but I wish we would get some discussion and other opinions .Its difficult to find good descripions of the hydrolics of the process and the relation to fish behaviour.
RT are you listening please give us the gospel.