Looks like Saturday is always an interesting day when it comes to the weather. The weather was quite dramatic on the 26 October 2013 (a saturday), with several storms possibly going supercellular. I managed to observe two of them from the complex where I live in Moreleta park. They were absolutely beautiful. I managed to shoot one in time lapse and it was incredible watching it change form and shape and seeing the anvil spread in the video. Unfortunately I never did manage get confirmation on whether the storms were indeed supercells. However, supercell or not, these storms were a wonder to watch. Definitely among the most beautiful cumulonimbus formations I've ever seen.
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| The backside of one of the possible supercells from Saturday 26 October 2013 |
So, another question. What is a supercell thunderstorm? What sets it apart from other types of thunderstorms? And more importantly, how common are supercell thunderstorms in South Africa?
Well first, here's my take on it. A supercell is basically nature's version of what separates the men from the boys. The supercell of course being the man and the other thunderstorm types being the boys.
Alright then, enough with my own definition of a supercell. Let's get to the serious part. A supercell is a intense long lived thunderstorm with a single rotating updraft called a mesocyclone. Supercells are also sometimes called rotating thunderstorms, for obvious reasons. They are also the rarest and potentially the most destructive type of thunderstorms.
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| The beautiful anvil at the front the storm |
What sets supercells apart from other thunderstorm types is their rotating updraft, or mesocylone. In addition to their severity and intensity, it is also their duration that sets them apart from other storms. While the mature stage of most other storms last anywhere from 20 to 40 minutes, supercell thunderstorms can last for several hours. It is partly this long duration that makes them so destructive. They also tend to produce the strongest winds, the biggest hail and the strongest tornadoes. Supercells occur in many parts of the world. The general wisdom is that they can occur anywhere where thunderstorms occur regularly, although it is not always that straight forward.
So where do supercells most commonly occur?
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| A 3D image of a supercell showing all it known characteristics. (Courtesy of http://www.srh.noaa.gov/bmx/?n=supercell) |
Supercell thunderstorms are most common in the central plains of the United States. Not surprising since that's where tornadoes most commonly occur. But they can occur in other parts of the country and the world. Other parts of the world where supercells are regularly observed include Canada, Australia, South Africa, Argentina, Brazil, China, Russia and large parts of Europe. These places all have one thing in common. With largely the exception of Brazil, they're all located in the mid latitudes.
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| The storm in the previous two images in full view. |
So how often do supercells occur in South Africa?
Unfortunately there isn't a lot of information on supercell thunderstorms in South Africa, but it is known that they are quite common.
They most commonly occur in the provinces of Kwazulu-Natal, Gauteng and the Free State, although they can occur in the other provinces as well. And like their counterparts in the central plains of the US, they can produce a whole variety of severe weather ranging from large hail, strong winds, heavy rain and tornadoes.
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| One of the best supercell photos ever shot. A classic mothership supercell over Texas in 29 May 2001 (Courtesy of Carsten Peter) |
Notable supercells that have occurred in South Africa include the supercells that produced the two tornadoes that devastated the township of Duduza in the east of Johannesburg and in the town of Ficksburg in the Freestate on the 3 October 2011. What was interesting about these tornadoes is that they occurred at almost the same time on the same day, which is very rare indeed.
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| Another possible supercell thunderstorm outside Pretoria on the 26 October 2013 |
http://www.youtube.com/watch?v=rdD7yn7mCTg
Click on the link above if you would like see to a time lapse video of the storm in the above image.
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