September 18, 2007
At the end of a very nice boat trip in the Seven Lake District in Patagonia (southern Argentina), I noticed this stacked lenticular cloud formation. In combination with the sunlight beam appearing to cross the larger cloud, I felt as though I was in the middle of a science fiction movie. Alas, aliens didn't abduct me, and I could safely disembark in the beautiful port of Bariloche. Photo taken on December 24, 2004.
Lenticular clouds form when stable but a nearly saturated layer of air is forced to flow over elevated terrain, typically mountain ranges. The lifting cools the air to saturation and cloud formation, but doesn't lead to convection or instability. These clouds are usually hallmarks of stable weather conditions.