Big Wednesday Revisited – Gale Force Downwind Dash
Gale Force? Interest has been expressed in some quarters as to just how strong the wind was last Wednesday when the Downwind Dash records were beaten. Jean Tresfon, sent us the story of what happened at his factory - which is located near to Milnerton and probably experienced the same wind conditions.
The Beaufort Scale includes descriptions of what happens on land (this table copied from Wikipedia).
|
Beaufort number |
Wind speed |
Mean wind speed (kn / km/h / mph) |
Description |
Wave height |
Sea conditions |
Land conditions |
||||
|
9 |
41-47 |
76-87 |
47-54 |
20.8-24.4 |
44 / 81 / 50 |
Strong Gale |
7 |
23 |
High waves (6-7 m) with dense foam. Wave crests start to roll over. Considerable spray. |
Light structure damage. |
|
10 |
48-55 |
88-102 |
55-63 |
24.5-28.4 |
52 / 96 / 60 |
9 |
29.5 |
Very high waves. The sea surface is white and there is considerable tumbling. Visibility is reduced. |
Trees uprooted. Considerable structural damage. |
|
What's interesting about this is the "structural damage" described by Jean, below. This confirms that the conditions equated to Force 9/10.
So how strong was the wind actually?
By Jean Tresfon
The SE has visited Cape Town with a vengeance these past two weeks. The Roman Rock weather station has recorded constant SE winds averaging over 30 knots for days on end, with gusts easily reaching 45 knots. There was a brief respite last Sunday morning as a weak front passed over the city bringing a fresh NW wind and some rain, but the SE was back by the same evening, reasserting itself as the dominant force in nature's weather arsenal for the season. As a paddler and diver I tend to keep a close eye on the weather (my wife complains that her entire life is "weather dependant"!) and these last two weeks have been something special, even in a city with such a reputation for the SE that we even have a name for it!
I live in Noordhoek and work in Salt River, with both areas strangely enough being similarly affected by the SE. I leave for work in the mornings with my car being thrown around by the wind as I crest Ou Kaapse Weg, drive through a still and windless Newlands and re-enter the battle zone on the Salt River bridge.
The SE has become something of a joke at my brick factory, with our raw material stocks of sand and crusher dust being literally blown away during the night. Over the ten years I have been at our Salt River premises we have had some strong winds, but this past week has to take the cake!
It all started on Monday, when our sign at the entrance to the Transnet Industrial Park was demolished by the wind. The sign actually consists of two signs erected back to back to effect bi-directional coverage on Voortrekker Rd. They are constructed from chromadek steel sheeting bolted to galvanized steel frames which are in turn bolted onto 2.5 inch diameter galvanized steel pipes. The signs have been in place for over two years and have withstood some serious wind, until now.
The east facing sign was blown over, with one of the steel frame poles snapping off at ground level. The west facing sign is still upright but the entire chromadek sheeting is gone, ripped right off the frame and disappeared into thin air!
Yesterday (Thursday) things got really interesting and even life threatening.
Right about the time that Dawid Mocke was breaking records in False Bay, a gust of wind caused havoc at our premises.
Our neighbouring tenant in the Transnet Park is the Gateway Containers storage yard. The containers are stacked on top of each other up to six high. These are 12m long refrigerated containers weighing over 6 metric tons each, that's 6000kg or more apiece! During yesterday's gust one of these bus sized beasts was blown off the top of the stack, over the boundary fence and fell 20m into our sand bay, narrowly missing our digger-loader driver. Luckily for the container company it had a relatively soft landing on the sand pile instead of smashing into the concrete floor.
This is a first in the ten years at these premises! So I was not really surprised to hear that this has been the week for record breaking, I was more amazed that there are paddlers out there with enough skill and courage to tackle these conditions, which surely must be some of the more challenging to be found anywhere in the world. This is after all "The Cape of Storms"!
Ian Black's Paddle
Ian beat the Downwind Dash record by one second according to the official timekeepers, but this doesn't reflect the reality of how fast he did the run...
"I didn't realize it was actually a race," he said. "At the briefing we were told that it wasn't a race and that we were to stick together.
"But on the water the other guys just disappeared and so I put my head down and went for it."
It was Ian's first time on the route and he didn't know that you could go between the island and the shore to get into Big Bay. He was the only paddler to go around - and probably wasted a minute doing it.
And when he arrived, he didn't know that the three people on the beach were there to take times... "I thought they were there to help carry skis up the beach," he said. "So I stood there for a while waiting for them! Finally I saw that they were taking times and only then ran up the beach."
He'd found the conditions quite daunting. "That incredibly strong wind, the cold water, the sun going down. Yeah, it was a bit hectic."
Ian is sponsored by Honcho Surfskis and is paddling their new Xtreme ski. He had a phenomenal season in Cape Town in 2007, coming second overall in the Discovery Men's Health Series. Keep your eyes open for this paddler...
Video Clip from Richard Kohler
Richard's uploaded a video clip to blip.tv. Here's the URL: