October 18, 2015
Somewhere above you, light is arriving from places so distant their names feel like poetry.
Mammatus Clouds Over Saskatchewan
Birthday · October 18, 2015
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APOD published October 18, 2015. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
Why is this cloud so bubbly? Normally, cloud bottoms are flat. The flatness is caused by moist warm air that rises and cools and so condenses into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such pockets may occur in turbulent air near a thunderstorm. Resulting mammatus clouds can appear especially dramatic if sunlit from the side. These mammatus clouds were photographed over Regina, Saskatchewan, Canada during the summer of 2012.