LENTICULAR CLOUD LOOK LIKE UFO'S
Lenticular
clouds (Altocumulus lenticularis) are stationary lens-shaped clouds that form
at high altitudes, normally aligned perpendicular to the wind direction.
Lenticular clouds can be separated into altocumulus standing lenticularis
(ACSL), stratocumulus standing lenticular (SCSL), and cirrocumulus standing
lenticular (CCSL). Due to their shape, they have been offered as an explanation
for some Unidentified Flying Object (UFO) sightings.
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. If the temperature at the crest of the wave drops to the dew
point, moisture in the air may condense to form lenticular clouds. As the moist
air moves back down into the trough of the wave, the cloud may evaporate back
into vapor. Under certain conditions, long strings of lenticular clouds can
form near the crest of each successive wave, creating a formation known as a
"wave cloud." The wave systems cause large vertical air movements and
so enough water vapor may condense to produce precipitation. The clouds have
been mistaken for UFOs (or "visual cover" for UFOs) because these
clouds have a characteristic lens appearance and smooth saucer-like shape.
Bright colors (called irisation) are sometimes seen along the edge of
lenticular clouds. These clouds have also been known to form in cases where a
mountain does not exist, but rather as the result of shear winds created by a
front.
In : Amazing Facts