I got this picture in my email, sent by Edna who's wondering if it's real. It looks real to me. The picture is accompanied by the following text, which also sounds accurate to me (as a non-meteorologist):
MT. St. Helens, which sits about 30 miles from Vancouver, as the crow flies, continues to spew ash, while it is forming a lava dome in the crater and still having minor tremors. In this sunrise shot, she appears to be blowing smoke rings (and anything so benign is welcomed, given recent history.) What forms the "smoke rings" is the air flowing over the mountain getting pushed up higher as it goes up and over the top. The moisture content and initial temperature are just right so that the moisture condenses from a vapor to small particles at the higher altitude. When the moving air moves past the peak and comes down again, the particles evaporate back to an invisible vapor. The two "pancakes" describe that there are two layers of air for which this is happening, thus making this awesome picture possible.
And here's another photo of a 'pancake cloud' (also sent by Edna). I don't know where this one was taken.