RS-
Doing that comparison is not really a good one to do when it comes to the realities of weather. The atmospheric setup that produces the heavy, flooding rains in the warm season does not occur during the winter, or at least when it is cold enough for the precip to fall as snow. However, for the sake of dreaming, one could say that approximately 10-12" of snow would result from 1" of rain. Keep in mind the areas that were under 3-4 feet of water did not get 3-4 feet of rain, it was due to runoff from surrounding areas.
-John