Pruning a storm damaged conifer is a little different than pruning a broadleaf hardwood when damaged by high winds and water/ice weight. A typical conifer usually has only one central trunk with many lateral branches variously spaced along that bole and up to the apical tip. Also, sprouting new growth is not as common for conifers as is seen after hardwood damage - developing a new top is tricky.
An interesting report by the United States Forest Service indicates that uprooting is the most common failure in storm damaged conifers followed by bole, limb, and butt failures. Not much you can do with an uprooted conifer but stem and limb damage can be corrected depending on species and severity of damage.
Spruces and firs can produce a few weak new lateral branches but pines will rarely grow new branch growth. The good news is that all conifers will work hard to replace a lost top by using existing leaders if enough are left to support such growth. If a conifer has less than 10 percent of its top branches left, tree growth stops and survival is poor.
One thing to remember is the difference in how spruces, firs and pines adapt to top pruning. Pines will normally recover after a 50% top loss but not much less. Spruces are the most adaptable and can recover from a 75% top loss if pruned properly. Firs will adapt somewhere in between these percentages but no conifer can full recover with only a 10% top remaining.
Conifers that have lost tops in a storm should have their main stem trimmed back to within an inch or two of healthy lateral branches. Unfortunately, this is not economically feasible to do when significant damage occurs in a large forest. But it is practical when a high value specimen or favorite tree is harmed.
Cut the center snag at a slight (10°) angle to allow for water to runoff and especially if callous growth forms a water-holding pocket around the edge. Cutting back to the first live branch will encourage potential "new" leaders to form from the lateral branches nearest the top. If possible try to maintain just one new leader as developing multiple tops will create a tree very prone to further wind damage.
To encourage proper future shaping, the topping site might need to be revisited for further form enhancement the second year. Pines tend to do better with a single leader to gain height growth so further pruning may be necessary.