Mount Rainier is an active stratovolcano 45 miles southeast of Tacoma and 60 miles south-southeast of Seattle. Its last ...

An Air Force investigation later concluded that what Arnold really saw were disc-shaped wave clouds called lenticular clouds, which are not uncommon in the Cascades and on top of Mt. Rainier, the ...

Lenticular Clouds Shrouding the Peaks of Mount McKinley (Getty Images/Ron Sanford) On June 24, 1947, pilot Kenneth Arnold reported seeing multiple mysterious, gleaming circular objects along the crest ...

Lenticular is the overarching name given to those lens-like, stationary clouds that form because of some sort of obstruction, such as a mountain, to a moist airflow.

Lenticular clouds form repeatedly in some places. Here is why and how they form, and how they trick some people into thinking they're UFOs.

According to the Washington Post, lenticular clouds are often seen drifting above Mount Rainier. According to the Post, the cloud was probably around 10,000 to 20,000 feet high.