"Explanation: Normal cloud bottoms are flat. This is because moist warm air that rises and cools will condense 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 past summer."
"This image from the Landsat 5 satellite was acquired on October 27, 2011. The false-color view shows the high desert—bare soil and sparse vegetation appear in shades of brown and pink—and the deep green vegetation on the west side of the Cascade Mountains. The one blue spot is the glacial cap of Mount Hood.
The transition from green to brown is indicative of a rain shadow. Winds blow in from the west, carrying moisture from the Pacific Ocean. As the air moves across the landscape and up into the high elevations of the Cascade Range, air pressure decreases. The air cools and becomes unable to hold as much moisture, causing water to fall out as rain or snow. For this reason, the Cascades spend most of the year blanketed by cloud cover, and the frequent precipitation provides ample water for lush vegetation and gigantic trees.
On the eastern, leeward side of the mountains, the elevation drops, the air warms, and the air pressure increases. This effectively shuts off the rain because the air can better hold the remaining moisture. This effect is called a rain shadow and is largely responsible for the desert landscape beyond the mountains."
"A huge, lingering ridge of high pressure over the eastern half of the United States brought summer-like temperatures to North America in March 2012. The warm weather shattered records across the central and eastern United States and much of Canada."
"An invisible, ancient source of energy surrounds us—energy that powered the first explorations of the world, and that may be a key to the future. This map shows you the delicate tracery of wind flowing over the US right now."
"The photo above shows a cloudburst I observed just before sunset in Jones County, Texas on September 17, 2011. This rain shaft looked more foreboding than was actually the case and indeed any rain in drought-stricken Texas was welcome. January through July of 2011 was the driest six-month period ever recorded in Texas. Additionally, the summer of 2011 was the hottest on record. Convective storms can sometimes produce very localized rains; a deluge in a particular spot but only a few drops just a few hundred yards away."
"The mysterious “Relámpago del Catatumbo” (Catatumbo lightning) is a unique natural phenomenon in the world. Located on the mouth of the Catatumbo river at Lake Maracaibo (Venezuela), the phenomenon is a cloud-to-cloud lightning that forms a voltage arc more than five kilometre high during 140 to 160 nights a year, 10 hours a night, and as many as 280 times an hour."
Promotional Video of the "Catatumbo Lightning", tourist icon of the Zulia State,Venezuela. Declared Natural Patrimony of the Nation in 2007; and Natural Heriage of Humanity by UNESCO.
Photographer : Hector Fabian Garrido
"The photo above showing a sensational display of lenticular clouds was snapped near La Rioja, Argentina, at the base of the Andes Mountains, on September 9, 2011. I was doing seismic testing just after sunrise and was taken aback by the gold and tawny wave clouds that appeared across much of the sky. These lenticulars took shape to the lee (east) of the Andes, just west of my location -- the Sun was behind the camera. Lenticular clouds are generally orographic in origin, forming in lee waves when air is forced to rise over elevated terrain. On this early spring morning, the smooth structure of the waves, the illumination by the low Sun, and the absence of other types of clouds, gave the sky a surreal look."
This shot, taken in May 2010 at Nødebohuse, North Zealand, in Denmark, shows a natural phenomenon referred to as a solar pillar. These vertical beams of light areusually created in cold air by ice crystals falling from high clouds. The crystals are sometimes flat, and air resistance will cause them to float flatly, rather than knifing downward on edge. As sunlight reflects off the crystals, the resulting column of light shining up into the sky seems to come from the sun, but in reality it's just a few miles away from the observer.