SURFING A GUST-FRONT
Author: Tristam Burrell
We are on top of Arthur's Seat in the Central Berg, in search of Vultures, which British pilots Tim and Adrian are hoping to film from the air. There is a large storm 10 km behind us in the Main Berg, and the rain is advancing steadily towards us. Arthur, Roy, Tim, Adrian and I take off into a light NE wind direction. We get a few hundred meters ATO and fly forward, away from the storm. Roy lands on the plateau. We continue flying away from the mountain and all get quite low. Tim and Adrian land and announce the wind has changed by 180° and is getting stronger. Arthur and I find a scrappy little thermal very low, and start climbing out.
The gust front hits Tim and Adrian on the ground and they report wind speeds of over 45 km/h. I tell Arthur we have to run with the gust front, so we stand on our speed bars and start surfing. We race along, climbing steadily at up to 7m/sec.
At 600m ATO Arthur tells me we are going to be sucked into the cloud. I radio back that he's wrong, and that we are surfing the gust front. He decides it's time to get down, so pulls big ears but continues to climb at 4 m/sec. He then B-lines and starts a slow decent (2-3 m/sec). After 1 or 2 minutes his arms grow tired, so he cranks his Zen-2 into a deep spiral.
After a few seconds he hits violent turbulence and the inside wing folds in. Arthur is flung over the canopy. His glider crumples up and then reinflates with a bang. The glider spins several times and his lines are twisted several turns. He is now 400m AGL and contemplates throwing his reserve. His glider collapses violently again, then re-inflates, but is parachutal. He pushes out on his speed-bar and his glider front collapses. He comes off speedbar and goes parachutal again. He plays around with the trim adjustments, and finally settles into a steady 3 m/sec descent. He lands hard but safely on his Cygnus airbag, just before the big gust hits. Arthur rugby tackles his glider to stop it reinflating and dragging him. A farmer arrives, and helps him pack away the wildly flapping glider.
Meanwhile, I have decided the safest option is to out-run the storm and keep surfing. I am still on my speedbar and continue to climb to 1100m ATO. I have a steady groundspeed of 50km/h and am heading straight for Winterton. There is a huge fire in a field before Winterton, and the smoke is drifting towards me. I reach 1400m ATO and look back at the storm. I get quite a fright as it's right behind me. Tim and Adrian report gale force winds on the ground and that Roy and Gavin are being pelted with giant hailstones the size of golf balls. I look down at the fire, which is about 2km away, and to my horror see the lowest 1000m of smoke change direction. The gale force wind fuels the fire and the smoke is screaming horizontally along the ground, for kilometers, away from me.
I realise the gust-front has overtaken me, and watch with apprehension as my groundspeed starts to drop …40 …30 …20 …10 …4 …2 …0 km/h. I think "Shit, I'm standing still !!" I'm still on my speedbar. Then my GPS starts to register …5 …10 …25 …45 km/h. I am now being sucked backwards into the storm I thought I was going to out-run !! I'm starting to run out of options.
I am now 2100m AGL. I turn to look at the storm again. It's a real Drakensberg Beaut !!! It towers above me, black and ominous, lightening inside it makes it glow like a Christmas tree. A loud clap of thunder goes off like a bomb next to my ear. I almost drop my toggles in fright as the sound reverberates through my bones. I've often heard thunder, but never this close or loud. This is very, very different! I am dealing with one mean storm ! I look down and see the column of rain and hail below it, while ghostly mist is swirling everywhere. The ground far below me starts to disappear in huge red dust-storms emanating from all the ploughed fields. Huge tentacles reach out from the cloud like it is some kind of giant Octopus. The sight is from another world ! I curse myself for not having my camera.
"Maybe Arthur was right, it's time to get down !!" I decide. I put my trusty Bagheera into the mother-of-all-spirals. At 1200m ATO I hit the first turbulence, and my glider crumples-up and falls below me. I am flung over it several times and, on two occasions, part of the canopy smacks against my harness. I keep stabilising the canopy and then, without warning, it collapses violently and falls below me. I have never seen a glider behave like this before. At times it deflates and looks like a coiled snake, then partially re-inflates into wild spirals, then completely deflates and flicks behind and below me. At times I'm not sure whether to catch it in the violent pitches or let it reinflate. After 500m of this I think to myself "OK, enough is enough!"
I take a wrap jam down the brakes and put my glider into a full-stall. This works pretty well. I start to lose height at a drastic rate while the glider flaps away. At least the canopy is above me now. 300m AGL I come out of the stall and re-assess the situation. I am about 5km North West of where the gust-front overtook me, and I am MOVING !!! I stand on my speedbar and, facing into wind, I have a BACKWARD ground speed of 78 km/h !!! The landscape is racing by below me. Landing is going to be very interesting !!! I B-line a bit lower and 100m above the ground pull in the Big-Ears and stand on my speedbar for all I'm worth, trying to get every bit of speed possible, so as to reduce my alarming backward ground speed.
I look behind me. There is a dam up ahead (behind), and I'm on final backward approach. For a second I contemplate allowing myself to get blown into the dam. After all, it'll be less painful than the ground. The surface of the dam is being whipped into a frenzy by the wind. Then I am alongside the dam. I'm getting blown paralell to it. I sink lower and my groundspeed drops. I enter a deep valley, still backwards and on my speed bar. I sink into the valley, and my speed slows down more. 5m off the ground I slow to an acceptable 20km/h backward speed. I land easily, collapsing my glider with the C-risers as my feet touch the ground, doing a backward roll or two. I pack up and walk to the road, where I find Arthur and the farmer.
On inspection of Arthur's glider, we found his glider had snapped A and B lines in the turbulence and had a 45 cm tear in the centre of the canopy, running from the A to the C lines.
Tris