Mammatus Clouds above Newland, North Carolina

July 13, 2011

MammatusinNCIMGP3602 (3) 
Photographer: Rich Bruner
Summary Author: Rich Bruner; Jim Foster

Severe thunderstorms rolled through western North Carolina on the evening of June 7, 2011. Though we were spared the worst of the wind and rain, ominous looking mammatus clouds glared down at storm's end. Whenever mammatus clouds are observed, it's recognized that downdrafts of cool air are an active feature of the storm system.

The orange color of the clouds is attributed to a low Sun. Sunlight has been attenuated by the greater path-length that occurs when the Sun lies near or below the horizon. Here, the Sun has already set (at the surface), but the lofty clouds are still exposed to the Sun's lingering rays.

Photo details: Camera Maker: PENTAX; Camera Model: PENTAX Optio W80; Focal Length: 6.1mm (35mm equivalent: 34mm); Aperture: f/3.8; Exposure Time: 0.020 s (1/50); ISO equiv: 160; Exposure Bias: none; Metering Mode: Matrix; White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB.