The heavens declare the glory of God;
the skies proclaim the work of his hands.
-Psalm 19:1

Do you know that God controls the clouds and makes his lightning flash?
-Job 37:15

Friday, July 17, 2009

Amazing shelf clouds...

A SHELF CLOUD is a type of arcus cloud.

An arcus cloud is a low, horizontal cloud formation associated with the leading edge of thunderstorm outflow, or occasionally with a cold front even in the absence of thunderstorms. Roll clouds and SHELF CLOUDS are the two types of arcus clouds, slight variations in their generation and look being the difference.

[A] shelf cloud is attached to the base of the parent cloud (usually a thunderstorm). Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent and wind-torn.

Occasionally people seeing a shelf cloud may believe they have seen a wall cloud. This is a common mistake, since an approaching shelf cloud appears to form a wall made of cloud. Generally speaking, a shelf cloud appears on the leading edge of a storm, and a wall cloud will usually be at the rear of the storm.
Yesterday, people shared shelf clouds they've encountered over the summer in the eastern part of the country... My personal best was in South Dakota... I'll share that in a minute...

With permission, here is a shelf cloud that Annie B. encountered during her vacation at Daytona Beach.... when Annie's friend Matt saw that, he shared with her his shot on his south Georgia farm of an awesome shelf in Lenox, GA. He also gave me permission to share...Looks like a scene straight out of the plains, doesn't it? Great shots, guys and thanks for sharing.

Here is my SD shelf cloud... what an amazing experience this was.They look ominous for a reason... they are generally a good indication of some powerful weather coming. Mine incorporated an amazingly powerful sand storm and winds that knocked down a tractor trailer. The other side held tornadic wall clouds... with multiple funnels. If you see something like this approaching, find a safe spot.
Sign of danger
A sharp, strong gust front will cause the lowest part of the leading edge of an arcus to be ragged and lined with rising fractus clouds. In a severe case there will be vortices along the edge with twisting masses of scud that may reach to the ground or be accompanied by rising dust. A very low shelf cloud accompanied by these signs is the best indicator that a potentially violent wind squall is approaching. An extreme example of this phenomenon looks almost like a tornado and is known as a gustnado.
Have a great day and wonderful weekend!


  1. Very cool pics!

    And educational too. Being in the midwest, we watch out for these clouds because they are an indicator of possible tornados.

    Clouds are just facinating, aren't they?

  2. Scary clouds!!!!

  3. Wonderful! Gorgeous! I've never seen clouds like these before. And I learnt something new - a shelf and a wall cloud. All the photos are beautiful! :)

  4. Whoa, I'd be lookin' around for Will Smith and Jeff Goldblum ("Independence Day")

  5. Excellent photos and a good little meteorology lesson. Thanks.

  6. That first picture is amazing. The clouds look like a wave coming into the beach

  7. Interesting and beautiful!

  8. Wow! I have never seen anything like that! I cannot believe how many different cloud types there are and I have seen so few! Thank you for the great pictures and the information.

  9. What beautiful photos! I had no idea what this fascinating cloud is called. I've taken some photos of these kinds of clouds--they are beautiful, and a little scary looking.

  10. Awesome photos but if I were at that beach and saw those clouds I think I would head home!

  11. Fascinating photos! My husband and I just drove cross country from Calif to Rhode Island. My biggest fear was running into a big storm. Thankfully it was clear sailing all the way. No tonadoes, just terrible drivers in certain states :)


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