Erica's Answer:
Virga happens when clouds precipitate into a very dry atmosphere. The dry air below the cloud soaks up the precipitation like a sponge, and all that rain and snow evaporates before it has a chance to reach ground level. Virga happens occasionally in our area. To locate virga, look for dark streaks below the base of a cloud. If the streaks don't reach the ground, you're looking at virga!- Erica