LENTICULAR CLOUDS
What is Lenticular cloud?
Lenticular clouds, technically known as altocumulus standing lenticularis, are stationary lens-shaped clouds that form at high altitudes, normally aligned at right-angles to the wind direction.
Where stable moist air flows over a mountain or a range of mountains, a series of large-scale standing waves may form on the downwind side. Lenticular clouds sometimes form at the crests of these waves. Under certain conditions, long strings of lenticular clouds can form, creating a formation known as a wave cloud.
Power pilots tend to avoid flying near lenticular clouds because of the turbulence of the rotor systems that accompany them, but sailplane pilots actively seek them out. This is because the systems of atmospheric standing waves that cause "lennies" (as they are sometimes familiarly called) also involve large vertical air movements, and the precise location of the rising air mass is fairly easy to predict from the orientation of the clouds.
"Wave lift" of this kind is often very smooth and strong, and enables gliders to soar to remarkable altitudes and great distances. The current gliding world records for both distance (over 3,000km) and altitude (14,938m) were set using such lift.
Lenticular clouds have been mistaken for UFOs (or "visual cover" for UFOs) because these clouds have a characteristic lens appearance and smooth saucer-like shape.
Lenticular clouds, technically known as altocumulus standing lenticularis, are stationary lens-shaped clouds that form at high altitudes, normally aligned at right-angles to the wind direction.
Where stable moist air flows over a mountain or a range of mountains, a series of large-scale standing waves may form on the downwind side. Lenticular clouds sometimes form at the crests of these waves. Under certain conditions, long strings of lenticular clouds can form, creating a formation known as a wave cloud.
Power pilots tend to avoid flying near lenticular clouds because of the turbulence of the rotor systems that accompany them, but sailplane pilots actively seek them out. This is because the systems of atmospheric standing waves that cause "lennies" (as they are sometimes familiarly called) also involve large vertical air movements, and the precise location of the rising air mass is fairly easy to predict from the orientation of the clouds.
"Wave lift" of this kind is often very smooth and strong, and enables gliders to soar to remarkable altitudes and great distances. The current gliding world records for both distance (over 3,000km) and altitude (14,938m) were set using such lift.
Lenticular clouds have been mistaken for UFOs (or "visual cover" for UFOs) because these clouds have a characteristic lens appearance and smooth saucer-like shape.
Forming of banner cloud
Mt Fuji,Japan
McKinnon Reserve ,Lake Ohau Alpine Village, New Zealand
Taken from McKinnon Reserve, Stacked Lenticular Clouds above Ben Ohau Range as seen from Lake Ahau Alpine Village, at midday, 12:15 pm
Taken from McKinnon Reserve, Stacked Lenticular Clouds above Ben Ohau Range as seen from Lake Ahau Alpine Village, at midday, 12:15 pm
Stacked Lenticular Clouds above Ben Ohau Range as seen from Lake Ahau Alpine Village Sunset 10 March 2008, Sunset 8:15 Pm
The shape and number of clouds in the pancake like stack changed as new lennies formed and the older clouds at the top of the stack disappeared. Since lenticular clouds are formed by strong wind we knew that although the air was calm where we were that wind was coming. By late afternoon, the wind appeared at the far end of Lake Ohau, moved toward us and about 20 minutes later, reached Ohau Village at gale strength. The second photo above shows these clouds at sunset.
The shape and number of clouds in the pancake like stack changed as new lennies formed and the older clouds at the top of the stack disappeared. Since lenticular clouds are formed by strong wind we knew that although the air was calm where we were that wind was coming. By late afternoon, the wind appeared at the far end of Lake Ohau, moved toward us and about 20 minutes later, reached Ohau Village at gale strength. The second photo above shows these clouds at sunset.
Licancabur Expedition ,November 19, 2003 On the Summit. Lenticular Clouds. Tuesday, November 11, 2003, 03:44 PM US/Pacific
Lamarck Col, a high pass on the crest of California's Sierra Nevada mountains
Lenticular Clouds at sunset over Lamarck Col, a high pass on the crest of California's Sierra Nevada mountains, along the eastern boundary of Sequoia/Kings Canyon National Parks. This high altitude cross country route is a shortcut from Bishop to the heart of the High Sierra and leads into Evolution Valley, along the John Muir Trail.
Lenticular Clouds at sunset over Lamarck Col, a high pass on the crest of California's Sierra Nevada mountains, along the eastern boundary of Sequoia/Kings Canyon National Parks. This high altitude cross country route is a shortcut from Bishop to the heart of the High Sierra and leads into Evolution Valley, along the John Muir Trail.
Sedona, Arizona Dec. 26, 2006
Lenticular Clouds over the Els Ports