Archive - Lenticular Cloud Display

November 28, 2020

02clouds copy

Every weekend we present a notable item from our archives. This EPOD was originally published November 28, 2003.

Provided and copyright: Bill Willenberg
Summary authors & editors: Bill Willenberg; Jim Foster

The above photo shows but a glimpse of a spectacular lenticular cloud display, captured late in the day in mid-October, northwest of Salem, Oregon. This 8-layer cloud stack was the finale of a delightful orographic concert. On this particular afternoon, lenticular clouds were observed over the Willamette Valley, the Cascades Range (east of Salem) and the Salem Hills (south of Salem), but the few lenticular stacks that formed were confined to Oregon's coastal range and the Eola Hills. Lens-shaped lenticular clouds can form when moist air is cooled to the dewpoint as it's forced up over mountain slopes -- wherever stable moist air flows over a mountain range. As this happens, sometimes a series of wave clouds are created on the downwind or lee side of the range. If conditions are just right (moist layers are in rather close proximity), the clouds can appear to stack upon one another.

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