Cloud of the Month

August 2006

Cloud of the Month for August 2006

‘Surf’s Up’ at 24,000ft over Georgia, US.

The classic 1964 surfing documentary, The Endless Summer, followed the adventures of three surfers traveling from Malibu to Ghana, via Nigeria, Australia, New Zealand, Tahiti, and Hawaii in search of the perfect wave. Cloudspotters can experience their own perfect wave too, without ever having to leave home – all they need is a lot of patience. The only down side to the ultimate aerial breaker, is that it has the particularly un-hip name of the ‘Kelvin-Helmholtz cloud’.

The breaking waveforms of ‘Kelv-Helmz’ (as they aren’t known) are the result of shearing winds up at cloud level. A particular type of turbulence can develop in a layer of Cirrus cloud, which happens to form below an inversion* between air currents of differing speeds and/or directions. Sea waves break as their bases are slowed down upon reaching shallow water and their crests surge ahead. Cloud waves break in the same way: when their crests are pushed ahead of their troughs by the difference in air currents.

Though spotter-dudes won’t have to cross the world to see this formation, those in search of the perfect Kelvin-Helmholtz will have to wait a while. This most beautiful and transient of formations may appear over most regions of the world but it only ever does so on the rarest of occasions.

*An inversion is a region where air temperatures change with altitude in such a way as to act as an invisible ‘ceiling’ that stops clouds from rising through it.

Photograph © Brian Wong

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19 comments have been made

  1. chieko16 Jun 2011

    I have been lucky enough to have seen these clouds this year in between Santa Fe and Albuquerque, NM at dusk. I watched them form and was completely fascinated by them as I drove south on the highway. Unfortunately, I had no camera with me but they are ingrained in my memory!

  2. pony express5 Oct 2011

    Today I saw them, the imfomiss kelvin-helmholtz clouds comming home from work. Unfortunately they were gone within a few minutes, so I did’nt have time to take pictures.Where were these clouds seen, Brampton,Ontario,Canada

  3. Jo L21 Oct 2011

    I saw these clouds over the Atlantic Ocean on my birthday this year, 13 October. I was surfing at Saunton, North Devon, UK. My friends were a long way down the beach and were too busy watching the waves on the ocean to see these amazing formations in the sky! I had to make some new friends to share them with;)
    What a wonderful birthday gift, perfect waves twice over!

  4. SOettle12 Nov 2011

    I saw some over Jacksonville, Illinois today. Sadly, my camera wasn’t with me. :( They were pretty awesome!

  5. Elizabeth Taylor20 Dec 2011

    These were seen Dec 16,2011 in Birmingham,Ala on Utube home vid called …Tsunami wave cloud over Birmingham,Ala

  6. ana20 Dec 2011

    sorry to tell you but these clouds are not good sign… Earth changes are violent and upheaval at our doorstep
    may look “nice” but, as sign, not at all…

  7. Mary2 Jan 2012

    Ana, I’m interested in hearing & learning more about your statement, I believe you are right! Please email me with your facts, thoughts, and anything at Thank you

  8. J-Dawn4 Feb 2012

    I saw those the other day and was fortunate enough to have my camera with me. Only got one or two good shots before they leveled off.

  9. Ian Uzzell19 Mar 2012

    I saw some yesterday whilst driving. I passed my camera to my wife who took some photos before they dissipated. I will post on the photo section later

  10. Jen Fountain24 Mar 2012

    We had some here in Honesdale, PA today. I was only able to take two photos – very cool!

  11. Warren Arbuckle13 Nov 2012

    I saw my first Kelvin-Helmholtz cloud formation on 30/10/2012, 5.20pm above Margate, Tasmania. They were formed atop of a Lenticular cloud, so even rarer to see. I managed to scramble for my camera , but only got a couple of shots as they were collapsing. Very special moment :-)

  12. giddens4 Dec 2012

    I saw these fabulous clouds in the morning at a B&B in Lynton,Devon in October this year.I took several photos but don’t know how to get them from my camera to the website!

  13. Savitri Simpson27 Dec 2012

    I saw them on the day before 12-21-12. You can imagine what I thought? Never saw them before, but nice to know what they are. I got a pretty good photo with a cell phone (this is in No. Cal). Should I send the photo somewhere?

  14. Anonymous6 Feb 2013

    nice ion

  15. Anonymous6 Feb 2013

    sorry nice info

  16. qwertydog13 Feb 2013

    Saw these hidden within stratocumulus clouds one day.

  17. David Geddes14 Nov 2013

    Sunday 10 Nov 2013. Observed a beautiful display of KHI in the sky west of Rum and Skye (Scotland) amidst a setting sun. Pics on web site per URL given in the album ‘View from Meall Gorm’.

  18. David Geddes14 Nov 2013

    Direct link to web album image The cloud display was present for at least 2 hours. One large commercial jet going west threaded the cloud spirals.

  19. Alicia13 Dec 2013

    Just saw some during the sun rise in DC this AM. They were pink!

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