Frozen Cloud Streamers
March 23, 2007
The photo above showing glaciated virga was taken at 11:58 Universal Time (UT) on January 23, 2007, from Merida, Spain. (Sony DSC-P100, zoom x3). Virga is precipitation that evaporates before reaching the ground surface. Here, It seems that ice crystals are falling from a layer of altostratus clouds. These clouds consist of supercooled water droplets, and when they freeze, the crystals that result can grow quite rapidly since the vapor pressure of water vapor over ice is small compared to the vapor pressure of water vapor over liquid water.