Severe Storm Near Richmond, Virginia
July 13, 2012
The photo above showing a dramatic storm cloud approaching Richmond, Virginia was taken in the late afternoon on June 30, 2012; the day following the powerful derecho event that affected much of the lower Great Lakes and Mid-Atlantic regions of the U.S. This is another example of a shelf cloud or arc cloud (see yesterday's Earth Science Picture of the Day). These fearsome looking clouds mark areas of outflow (downdrafts) in convective storm systems that often form ahead of a cold front. Though the wind noticeably kicked up as this storm passed, damage at this particular location was minimal.
Photo details: Camera Maker: Canon; Camera Model: Canon EOS REBEL T3i; Lens: EF24-105mm f/4L IS USM; Focal Length: 24mm; Aperture: f/4.5; Exposure Time: 0.020 s (1/50); ISO equiv: 400; Exposure Bias: none; Metering Mode: Matrix; Exposure: aperture priority (semi-auto); White Balance: Auto; Flash Fired: No (enforced); A series of 4 vertical shots converted into a panorama using Adobe Photoshop Lightroom 4.1 (Windows).