Lenticular clouds are actually quite rare, only occurring under specific conditions during the course of the year. They often resemble flying saucers and can have layers like a cake, tending to remain stationary (due to the nature of a standing wave) and rotate. Lenticular clouds only form when you have stratification and layers of air that have a relative humidity that is very near 100%. The lifting forced by Marys Peak or nearby Grass Mountain reduces the local air temperature so that layer reaches its LCL as it rises. As the air is pushed up and over it can form a cap cloud, orographic stratus, or a Lenticular cloud over the peak.
Additionally, lenticular clouds can form downwind of the peak as well. As the air sinks down the leeward side it bounces along a gravitational wave, rising again downwind. As it rises again it may reach the LCL once more. In this case a lenticular cloud can form. The air parcel continues to bob, but it is dampened as it flows. In some cases, the relative humidity of the parcel is high enough that lenticular clouds form on the second peak and sometimes even the third, as shown in the graphics above. Lenticular clouds are often accompanied with gusty west winds over the valley. For more information on general lenticular clouds, click here.
Our MissionThis webcam was funded by the National Science Foundation, with the original camera being installed by the Ocean Mixing Group on the roof of Burt Hall at Oregon State University on April 28th, 2010. The webcam is a part of experimental investigations into the physics of form drag in geophysical flows. The Biomicrometrology Group maintains the site as part of ongoing studies to understand and quantify interactions between the air, vegetation, and the land surface. The images obtained here are intended to complement studies of controlled flows over topographic obstacles in ocean and atmosphere. On August 4th, 2014, the Biomicrometeorology group at Oregon State University installed a new camera with near-infrared sensitivity to increase the window of viewability.
A collaborative, NSF-funded project by
C. Thomas, S. deSzoeke, L. Mahrt & E. Skyllingstad / OSU Atmospheric Sciences
J. Moum & J. Nash / OSU Ocean Mixing Group
Cloud Atlas compiled by REU student M. Spagnolo