Virga is precipitation that evaporates before hitting the ground. It often occurs in areas of low humidity, such as deserts. One important consequence is that the evaporation of the rain absorbs the latent heat from the air, creating a very cool and invisible parcel of air that may sink or even plummet quite rapidly toward the ground, resulting in a microburst or downburst (indications are high level virga and a ring of dust blown up on the ground).