Why the exclamation point? This is a type of mid-level cloud was in the news in the summer of 2009 because it was considered a newly discovered type of cloud. It matched none of the altocumulus or altostratus clouds in any official atlases and guides, so the founder of the Cloud Appreciation Society in England proposed that it be added to the list as Altocumulus undulatus asperatus. And now its official--the first cloud to be "discovered" in 50 years. I am using quotation marks because I am not totally convinced the cloud hasn't been in existence longer, but without the cloudspotters and photographers out there to prove it!
The photograph that got all of this started was taken in Des Moines, Iowa, where these clouds tend to precede significant rain storms. But lo and behold here they are in Olympia (all photos here). Ours are less dramatic and undulating, but still very rare and strange.
The photographs here were taken by the Accidental Naturalist this morning after an friend (who once, after a very long Olympia winter, said clouds "sucked"), called me to ask, "Are you looking at these incredible clouds?" I had just been outside trying to figure out what they were. I had never seen them before, in Olympia or anywhere else, but once the Iowa photograph hit the newspapers and Internet, everyone started looking and photos of this amazing cloud
started appearing on the Cloud Appreciation Society website. The photos are from all over the world--Italy, Argentina, Spain, Latvia, U.S. (Arizona), and Britain.
So what's so special about this cloud? It is a type of altocumulus cloud--mid-level cloud (6,500 to 18,000 feet above ground level) and appears in layers or patches of cloudlets. The Cloudspotter's Guide
describes the shape of this genus "rounded clumps, rolls, or almond/lenses." Undulatus
means to undulate, but with this variety, the rolls are more like a chaotic wave formation, hence the name asperatus
, which is Latin for "agitated."
The agitated rolls were rising up over the Black Hills to the west of where I was standing (about 10 miles away) and buy the time they were overhead, they had loosened a bit and were more like their altocumulus undulatus
selves. In a few hours, the asperatus features were gone.
Oh! The wild joys of living!