Sharks teeth

For some reason yesterday, the memory came in to my head of a time I was cycling home from work 2 or 3 years ago and noticed some superb clouds in the distance. They looked like curly sharks teeth. There were four of them, like a sort of curved over triangle. They were ace and all I had was a rubbish mobile phone to try and capture them on. I'm still a bit gutted about it.

So I was really chuffed to see these this morning. They are not as spectacular as the ones I saw originally but they are still pretty cool and still just as short lived. I took one photo straight away, ran across the road to take another without stupid streetlamps in, And that was it. They blew into boring streaks and were gone.

Thanks to Flumgummery for putting a name to this effect, the Kelvin-Helmholtz instability which i am now trying to commit to memory so I can impress my friends with it in the future. :-)