As we approach late February, the smallmouth rivers warm slightly. They do not get warm enough to prompt the bass to head for the shallows along the banks, but instead will remain in the deep sections. There are several 4 foot deep cuts that are 40 feet long below the river crossing ledges on the North Fork of the Shenandoah River. There is excellent hellgrammite habitat on both ends of these ledges and I usually catch my first smallmouth here on a Murray's Black Heavy Hellgrammite size 4.
Another approach is to use a canoe or kayak and fish upstream of the dams where the water is very deep. Get your fly as deep as you possibly can using split shot or a Murray's Fluorocarbon Sinking 6ft 2X leader.
Middle May to October is the best time to fish for the smallmouth as that is when the water is warm enough to prompt the bass to feed. So I will add posts as the conditions improve but if you cannot wait to get out then use the techniques I have listed above.