PUYALLUP, Wash. -- Dramatic cloud formation on Mt. Rainier aren't too uncommon, but perhaps no show was as incredible as the one that graced the mountain 10 years ago Wednesday.
For on Dec. 5, 2008, conditions were just perfect for a lenticular cloud display that caused jaws to drop across the region, and maybe a thought or two that the aliens had finally arrived.
Marcy LaGagnier was one of many photographers who had her camera ready when the clouds appeared.
"As a Puyallup-based photojournalist, I was fortunate enough to be in a prime location for the show from beginning to end with 153 images of the entire afternoon," she said.
Some of them are still on display at the Hangar Inn Restaurant at Thun Field to commemorate the event.
Luke Meyers was also a witness and took video of the display:
The cloud, known as a "lenticular cloud" is formed when you have three ingredients: Warm, moist air that is just on the cusp of saturation, laminar flow (when you have winds constant with height -- as in little to no turbulence or shear) and something big to get in the way, like, say, the region's tallest mountain.
When the air flows over the mountain, it will create waves downstream where the air is now going up and down, and up, and down -- like ripples on a pond or waves on the ocean.
When the air goes up, it cools a little bit and when conditions are on the cusp of saturation, that slight cooling is enough to create a cloud. When the air sinks back down again, an opposite drying effect occurs and the cloud disappears.
While to us it might look like the clouds are floating in place, in fact, the air is streaming through the cloud as it hovers there -- the cloud is just showcasing the right spot in the atmosphere where the air is undergoing its lift and sink. Sometimes this occurs right over the summit, giving the mountain a hat. Other times, it's just downstream.
To get the "stack of pancakes" look, you have this effect happening at multiple layers.
Ten years ago, it was very complex wind field that made such dramatic clouds.
"In retrospect, we learned so much more from December 5, 2008," LaGagnier said.