June 05, 2008
These eye-catching pancake-like lenticular clouds were observed in the Great Basin of northern Nevada on February 20, 2008. Lenticular clouds, also know as altocumulus standing lenticularis (ACSL), form when a stable but nearly saturated layer of air is forced to flow over elevated terrain, such as the Sierra Nevada Range. Lifting cools the air to saturation and forms clouds, but doesn't lead to convection or vertical cloud developments. Glider pilots love "lennies" as these clouds are fondly called, since they're indicators of up-drafts. Gliding records for both distance and altitude have been set using the exceptionally smooth lift provided when lennies are present.