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HeadClouds

in the

What happens after cloudbase? The perfect scenario is you arrive, turn and set off on glide. But it’s not always so simple. Some clouds try to suck you in, while others don’t let you near them. Sometimes it’s cold, dark and disorien-tating, other times you’ll float up bathed in sunshine. We asked three expert pilots for their advice...

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Clouds

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PREVIOUS PAGESA cloud-filled sky in Araxa Brazil. on days like these you might spend quite a lot of your flight close to base and thinking about avoiding going into cloud. Photo: Marcus King

ABOVECloud depth is key when assessing clouds. ‘one or two turns in a strong climb in deep cloud is enough to get you completely lost,’ says olympio. Photo: Fredrik Gustafsson

Olympio, thinking about flatland flying, do you have any rules of thumb about climbing to base and avoiding cloud? Cloud flying in the flats, although less critical than in the mountains, is still dangerous because of the possibility of loss of orientation, deep stall and collision with other gliders or aircraft. Not to mention overdevelopment and the associated death risks.

Before flying I usually look at the forecast of cloud depth. (Cloud depth also works as an indicator of potential overdevelopment.) XC Skies and other weather sites have cloud depth charts. While flying I look at the clouds to have an idea of how deep they are. The deeper they are in a given day the more conservative is my approach to cloud

flying. It is usually not a problem to fly in shallow clouds; on the contrary, it can be a lot of fun. Deep clouds, on the other hand, can become a problem.

If I am climbing under a deep cloud and I am far from its edge I usually leave the core I am climbing in before I get to base so as I’m closer to the edge. The closer I am to cloudbase the closer I want to be to the edge of the cloud so as to allow for a safe escape. (If upon approaching the edge you leave the climb by accident you can always go back to it. On the other hand, if you allow yourself to be sucked in you are left with no option but to look for an exit.) In most cases, even if you opt for the edge of the cloud you will still fly into it, but it will be easier and faster to find your way out. Going into a deep cloud far from its edge is very likely to

OUR PANEL OF EXPERTS

Olympio FaissolBrazilian flatland expert. on 22 october this year he flew 462km from Quixada, his second 400km of the week.

Kelly FarinaAn Alpine paragliding guide based in Austria, Kelly regularly guides courses in the Zillertal Valley and the Dolomites (www.austrianarena.com).

Adrian ThomasA competition pilot and twice British Paragliding Champion, Adrian is a pro-fessor at oxford university where he researches the biomechanics of flight.

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get you lost, which in turn may lead to a delayed exit and possibly a scary experience too.

Kelly, you’re an Alpine pilot. What’s your rule of thumb?A question I’m often asked is, ‘How close can you get?’ The simple answer is it depends on the size of the cloud. Being nervous of big clouds is healthy and there is limited longevity in taking risks. I am a big advocate of prevention rather than cure: thinking ahead instead of needing some funky ninja move to get out of danger. This is especially true when cloud flying.

One rule I pass on is the Forty Five Degree Rule. That is, keep the edge of cloudbase at 45-degrees to you. Our airspeed at trim is around 10+m/s, so if the climbs turn into 10m/s it will give you a 1:1 glide to the edge (10m/s forward and 10m/s vertical speed). You should kiss the edge of the cloud as you leave.

There is no downside to this rule. If pilots find the lift gets too weak they can always creep back under a big cloud. However, the pilot who is too deep and too close when things get strong will soon find themselves lost. Not a nice situation. It works also for streets and clouds up to any size within reason. Surfing up the 45-degree line and back down in sink then back under to ride the 45 again is something I call “barrel rolling”. Way quicker than any ninja move that will make you fly at 90-degrees off track to escape the clutches of a wet, dark and strong thermal top.

A lot of people take a turn or two into cloud. What do you think about this? Good or bad practice? Or depends?Kelly: It depends on the size of cloud and where you enter. If just at the edge then it’s not a problem. I make sure I can always see the sun if going into a cloud. Sometimes, if the cloud is just mist and I am alone I will turn many times through the fog, but only if the sun is always visible above. This lets you know it’s not that dense. However once you lose the sun it is very likely you’ll get disorientated very quickly.

Olympio: It depends on your position in relation to the cloud as well as on cloud depth. One or two turns in a strong climb associated with a deep cloud is enough to get you completely lost for several minutes. If you are close to the edge of the cloud and there are not many gliders around you it is usually no problem. Obviously, in gaggle flying it is always dangerous to take extra turns and go into a cloud, hence the heavy penalties for cloud flying in competitions.

This may be an obvious one, but what are the problems associated with flying in cloud, or very close to cloud?Olympio: In the flats number one is overdevelopment. We have all read the horror stories of pilots who were caught in CBs. In days in which there is potential for overdevelopment I usually set a very wide margin of safety when deciding whether to land, especially as two-liners do not spiral well.

Deep stalls are also common. I know of a few cases of pilots who experienced deep stalls because they went into big clouds, either to stretch the next (usually final) glide or just for the heck of it. Getting your glider wet is a dangerous practice, especially if you are flying two-liners. It should not be done.

Other potential problems are collision and loss of orientation, which delays your flight and compromises effective navigation.

Kelly: The main one is disorientation. If it’s a big cloud on a spring day pilots could easily find themselves climbing in all directions. If lucky they’ll pop out the side a few hundred metres above base. But if pilots play with fire in the middle of a Congestus cloud they could find themselves above 6,000m with iced lines and terribly cold. Remember that it’s turbulent inside a big cloud it can be tricky to even maintain direction.

Clouds that form lower than the surrounding peaks are dangerous for an entirely different reason: crashing into the mountain becomes a real possibility.

Personally, if the sky is so overdeveloped that I can’t stay out of clouds I will land as I am more worried about the cold air and rain falling out of overdeveloped clouds. Alpine valley systems are perfect funnels for this cold, shallow flow. Once venturi takes over it’s anyone’s guess as to the wind in the bottom of the valley. There will always be another day.

Are there ‘safe’ clouds that you would climb in, and ‘unsafe’ clouds that you avoid? Olympio: Again, cloud depth is key. Deep clouds are more dangerous, because you are more likely to have a delayed exit if sucked in and get your glider very wet in the process. Position in relation to the cloud is also key: it might be safe, for example, to climb under an isolated congestus provided you are close to the edge and have a safe escape route.

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IN THE THICK OF ITsometimes, base is a bit dark. this pilot might need an umbrella quite soon. you don’t want to get your glider wet as some gliders have a deep stall problem when wet. If you get rained on or you get wet in cloud, get on bar and fly until the glider has dried out. Photo: Martin scheel

If you start to get sucked in, what advice do you have for getting out quickly?Olympio: Before you get sucked in it is good to have a point downwind in your GPS you can fly to. Unless you have a big compass it is better to look at the compass page of your GPS and fly downwind towards that point (use the accelerator when possible). It is very easy to lose your bearing, so it is important to concentrate on maintaining it in order to fly straight. Cloud flying without a GPS can become an agonising experience. Attention to sunlight may also help as it indicates areas of less density. Unless the climb is weak always opt for a ‘horizontal escape’ as opposed to a ‘vertical escape’ like spiralling or B-lining.

Adrian: Spiralling or B-lining or full-stalling all have you descend in the same place. A thermal has inflow, particularly close to a sucking cloud where thermal strength is increasing. If you spiral or B-line or full-stall you will be sucked gently towards the strongest updraft and will stay there. Much better to fly in a straight line and get out of the updraft. Even in the strongest cloud-suck the updraft region is small, and there is sink nearby. It is very rare indeed to have an updraft more than a kilometre across. Even if you head the wrong way across such a monster updraft you only have to fly 1km to get to the other edge at the absolute maximum, and at trim speed that is going to take you a little less than two minutes, provided you fly in a straight line.

That is the key: fly in a straight line (in any direction) and you will get to the edge of the updraft. Obviously it is a good idea to fly towards the nearest edge of the cloud, but even if you are totally disorientated if you fly in a straight line you will exit the cloud.

Flying in a straight line in cloud is hard, since there are no visual references. You need to have instruments you can rely on, and need to believe what they tell you (it’s too easy to think the compass is lying). I find that it is entirely possible to follow the arrow on a GPS and fly reasonably straight in cloud, but it is much easier to use a compass. I use a cheap Silva orienteering compass – big expensive gimballed things are unnecessary. Even those joke keyring compasses give good enough information for what you need, which is just to keep flying in roughly the same direction for a minute or two. It is very easy to get very disorientated in cloud. I’ve emerged from cloud convinced I was going straight to find the world turning below me. You really need an instrument to guide you out of cloud!

Kelly: If you use the 45 degree rule things have to get pretty out of hand to get sucked inside. But if pilots overcook it I would recommend Big Ears, speed bar and make yourself as big to the airflow as possible, stand up if necessary. Hold your course and hope for the best. If deep in then a spiral may be useful until you can get to the 45 line. It may take a while and steep spirals have their own

Why on some days does the lift slow down get-ting to base, and on others the lift gets stronger as you get to base?Generally, if the day is unstable and clouds are tall it will be easy to get to base and on into the white-room if you want. on stable days, blue or with haze-domes or flat clouds, par-ticularly with an inversion limiting thermal tops, you may find climbs slow as you get towards cloudbase.

What happens when the climb goes into the cloud. What's going on?As the water vapour condenses to droplets it releases heat (we are more familiar with the opposite movement of heat – when sweat evaporates it cools you down – the same process going in opposite directions). that heat warms the air, which can re-energise the thermal increasing the climb rate. It is not unusual for the climb rate in a thermal to double once you go into cloud.

I've often heard people say lift gets turbulent inside clouds. Why is this?Because of the extra energy being released by water vapour condensing to cloud droplets.

Technically, is there a difference between strong lift and cloudsuck? Fundamentally, there is no difference.

Clouds are wet. What should I be aware of about flying with a wet glider? the issue is that some gliders have a deep stall problem when they get wet. Deep stall is difficult to recognise if you are not used to it, and can be hard to recover from. If you get your glider wet then it is re-ally important to keep the airspeed high. Get on the bar, and stay on the bar until it has dried out again. If that means until you land, stay on the bar all the way down – the last thing you want is to get a deep stall close to the ground. Don't muck about with this one: two people threw their reserves during the practice days at the Europeans this year after their gliders got only slightly moist.

Climbing up cloud on the outside is amazing...Climbing up the side of a cloud is an absolute privilege, so make the most of it. the trick is to maintain constant awareness of what the cloud is doing, and always move to clear air as soon as cloud starts to build around you. sometimes you can surf up the upwind sides of clouds because the thermal forming the cloud is blocking the wind to some degree, so the cloud behaves like a giant hill. sometimes wave is involved. In the Alps there is generally some sort of convergence going on, with drier air on one side and moister air on the other – like sea breezes – and then the trick is to stay in the dry air.

‘WHAT DO THE CLOUDS FEEL LIKE?’Adrian Thomas on the technicalities of clouds

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ON THE EDGEstaying well clear of the white stuff. Photograph: Fredrik Gustafsson

dangers. B line stall is an outdated method – it will be too slow and you have no real control.

When climbing under a cloud, how do you work out where the strongest part of the cloud is? Where’s the sweet spot, where’s the danger zone?Kelly: The danger zone is anywhere within the 45 degree cone (single cloud) or 45 degree edge if a street. Upwind edges are usually the best, and you can sometimes see from underneath where the cloud is darker, as that is the deeper part of the cloud. (Clouds are always white, it is just dark due to height and/or density.) When close you can also see tendrils, with experience these even tell you how strong the climb will be.

If there is a street along a ridge it is sometimes unwise to be trapped between the wall of rising air and the peaks themselves, as you have to go through the climb again to reach the safety of the valley floor.

At base it can be easy to get confused about direction. How do you tell where the next cloud is and which way you should leave?Olympio: Looking at the cloud shadows is an option. I usually decide where I want to head before reaching base. If I get sucked in, I concentrate on maintaining my bearing unchanged, unless I see sunlight on one of my sides (which may be an indication of an exit).

Kelly: Again, thinking and planning on the climb is king here. Making your next chess move whilst

climbing is infinitely better than being spat out of a climb high up with no idea where to head for next.

Finally, can you tell us what your personal rule is for flying and cloud and why? Olympio: I for my part fear big clouds. Luckily I never had any really bad experiences because I always managed to escape before it got too hairy. All of my experiences of cloud flying were very good ones, surfing their edges, getting out safely and not fearing the worst. But as a general rule, I avoid it.

Kelly: When the air is strong and deep and large cumulus are over the peaks I tend to always avoid flying in cloud as I just don’t like it. In the early years I got sucked in a few times but in strong air it can be quite unnerving. If in doubt, I leave earlier rather than later.

Adrian: I have played a lot with cloud-flying in the UK (where it is, according to the NAC, legal), and have come to the conclusion that it really doesn’t help with XC flying unless the distance between clouds is beyond glide-range, and even then it’s marginal. The problem is that while you are in cloud you have no idea what is going on around you, so you emerge from cloud and have to make an instant decision about where to go. Better to keep an eye on the next route options as you approach cloudbase, and kiss the wispies as you leave. Of course, playing with cloud for the sake of playing with cloud is just magic.

SUCKED IN“I followed a bunch of turkey vultures towards a cloud once, and watched them go straight under the dome of the cloudsuck, and straight up into cloud. never seen birds do that before. I was a little behind and below so I headed for the edge of the cloud, and I could see by the ground shadow that I was only a few hundred metres from the edge. Didn’t make it. Got sucked in. Picked a compass direction and headed that way, steadily climbing at 4m/s with Big Ears and half bar star-ing at the compass. Fifteen minutes later I emerged into a cloud-canyon, some 900m higher than I had gone in, having done 12km in a straight line. I surfed down the canyon in the clouds and popped out into the blue very relieved. When I looked back that cloud had gone from the little round cumulus I’d followed the birds into to a massive Cunimb. I glided straight on until I landed, then sat and watched the lightning show.” Adrian thomas