Lenticular cloud formation over Harold’s Cross, Dublin

Lenticular cloud formation over Harold's Cross, Dublin

A lenticular cloud formation over Harold’s Cross, Dublin, Ireland (June 30, 2015).

Lenticular Clouds are stationary lens-shaped clouds, technically known as Altocumulus lenticularis. They look so alien, they even have been offered as an explanation for some unidentified flying object (UFO) sightings.

Lenticular Clouds form at high altitudes: at the low altitudes, obstacles like hills, mountains, or even human-made objects i.e. tall buildings, bridges disrupt the flow of air into eddies. But, at high altitudes, 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.

Pilots of powered aircraft tend to avoid flying near lenticular clouds because of the turbulence of the rotor systems that accompany them, but glider pilots actively seek them out. 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 to great distances.

Photo: wikipedia

Leave a Reply