We say here that "the mountain makes it's own weather." At 14,000+ feet, when the conditions are right, the air flowing up and over Mount Rainier makes clouds. Sometimes there are lenticular clouds, which sit a ways above the top of the mountain and look like a stereotypical UFO--round and flat. I've watched the mountain on days where there's just a wisp of a cloud that comes and goes, and at those times it's easy to see that the air flow is creating the wisp of cloud. And then sometimes the clouds look like this:
This was taken on a beautifully sunny day, but as you see, the mountain does makes its own weather!