Cirrocumulus Sky Over Missouri

March 18, 2012


Photographer: Ramona Miller; Grant Miller
Summary Author: Grant Miller; Jim Foster

The photo above, captured about an hour before sunset at our home in west-central Missouri, shows a "mackerel sky" composed of cirrocumulus undulatus clouds. The rippling is a result of upper atmospheric waves. Cirrocumulus clouds form at altitudes above about 15,000 feet (4,572 m). They're composed of ice crystals and, as with most wave clouds, are oriented roughly perpendicular to the direction of the wind. This sort of sky is often indicative of an approaching front; a warm front ahead of a storm system. On this evening the National Weather Service forecast 100 percent chance of rain for our location the next day -- the forecast held. Photo taken on February 14, 2012.

Photo details: Camera Maker: Canon; Camera Model: Canon PowerShot A3300 IS; Focal Length: 5mm; Aperture: f/8.0; Exposure Time: 0.0016 s (1/640); ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB.