On Monday, 5 December 2016 22:24:15 UTC, Metman2012 wrote:
On 05/12/2016 19:16, Mike Causer wrote:
This evening around sunset there was some odd-looking cirrus. The
oddity was that the curvature seemed to be in the vertical plane, not
horizontal. I observed it over a period of 30 minutes from positions
about 1km apart (home to get camera and out again to find a fairly clear
horizon) and that impression persisted. Location East Cambridgeshire.

https://www.flickr.com/photos/54731504@N04/31405011106


The whole scene reminded me of the visiting our open-hearth steelworks
in Glasgow when I was an apprentice. Rivers of molten steel would run
in channels across the floor!


Any help with this would be appreciated.


Mike

Looks like it's a fallstreak hole, with the precipitation being blown by
upper winds into that shape. I'm interested if anyone has a better
explanation!

The obvious answer is:
Has anyone thought to ask Dawlish.

No?
Baa!