Kelvin-Helmholtz clouds

December 20, 2011 • 3:07 pm

Matthew Cobb called my attention to this link from GeekOSystem, which shows an amazing cloud formation near Birmingham, Alabama a few days ago:

A meterorologist on Reddit explains how this occurs:

Meteorologist here. These are indeed Kelvin-Helmholtz waves. What is happening is that the nocturnal near-surface layers (lowest 50-100m) of the atmosphere are much more stable than the layers above it in the mornings. Until the ground heats up due to daytime heating, the surface layers stay more stable than the air over it. Kelvin-Helmholtz waves occur when the wind shear between the layers destabilizes the topmost portion of that stable layer, and entrains the air into the unstable layer. What you see is stable air being lifted, cooled, and condensed so that this process becomes visible, though this commonly happens many places without being visible.

The same phenomenon occurs on other planets; here’s a photo from Wikipedia of the phenomenon on Saturn:

Here’s a video of the formation:

13 thoughts on “Kelvin-Helmholtz clouds

    1. I’d note that the Great Wave is part of the BBC podcast series “A History of the World in 100 Objects”.

      #093 Hokusai’s The Great Wave:

      Neil MacGregor, Director of the British Museum, examines The Great Wave by Hokusai, one of the defining images of the power of the sea. He discovers its production initiated a wider awareness of Japanese art and became emblematic of the opening up of the country in the second half of the 19th century. With contributions by Donald Keene and Christine Guth.

      I found it one of the more interesting episodes:

      http://downloads.bbc.co.uk/podcasts/radio4/ahow/ahow_20101013-1000a.mp3

      check out the rest here:

      http://www.bbc.co.uk/podcasts/series/ahow

    2. Thanks for reminding me of this emotionally evocative print.
      It is now the background “wallpaper” on all 4 screens on my main workstation.
      Looking at this image makes me feel good, for some inexplicable reason.

  1. Exactly my thought too, but I couldn’t remember the artist’s name or painting’s title. Thanx for fixing that in advance.

    1. I had a similar thought – dinosaurs (which to this day coexist with Alabamian creationists, you know) migrating across the Birmingham plateau.

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