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HeadClouds
IN
THE
What happens after cloudbase? Te perfect scenario is
you arrive, turn and set off on glide. But its not always sosimple. Some clouds try to suck you in, while others dont
let you near them. Sometimes its cold, dark and disorien-
tating, other times youll float up bathed in sunshine. We
asked three expert pilots for their advice...
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A cloud-filled sky in Araxa Brazil. Ondays like these you might spend quitea lot of your flight close to base and
thinking about avoiding going into cloud.Photo: Marcus King
ABOVE
Cloud depth is key when assessingclouds. One or two turns in a strongclimb in deep cloud is enough to get youcompletely 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 criticalthan 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. Te 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 farfrom its edge I usually leave the core I am climbing
in before I get to base so as Im closer to the edge.
Te 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
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OUR PANEL OF
EXPERTS
Olympio Faissol
Brazilian flatland expert. On 22
October this year he flew 462km
from Quixada, his second 400km of
the week.
Kelly Farina
An Alpine paragliding guide based
in Austria, Kelly regularly guides
courses in the Zillertal Valley and the
Dolomites (www.austrianarena.com).
Adrian Thomas
A competition pilot and twice British
Paragliding Champion, Adrian is a pro-
fessor at Oxford University where he
researches the biomechanics of flight.
CLOUDS CROSS COUNTRY 47
get you lost, which in turn may lead to a delayed
exit and possibly a scary experience too.
Kelly, youre an Alpine pilot. Whats your rule of
thumb?
A question Im often asked is, How close can you
get? Te 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. Tis is especially
true when cloud flying.
One rule I pass on is the Forty Five Degree Rule.
Tat 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.
Tere 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 its 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.
Tis lets you know its not that dense. However
once you lose the sun it is very likely youll getdisorientated 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.
Tis 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:he main one is disorientation. If its
a big cloud on a spring day pilots could easily
find themselves climbing in all directions. If
lucky theyll 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 its turbulent
inside a big cloud it can be tricky to even
maintain direction.
Clouds that form lower than the surroundingpeaks are dangerous for an entirely different
reason: crashing into the mountain becomes a
real possibility.
Personally, if the sky is so overdeveloped that
I cant 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 its anyones guess as to
the wind in the bottom of the valley. here 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 IT
Sometimes, base is a bit dark. This pilotmight need an umbrella quite soon. Youdont want to get your glider wet as somegliders have a deep stall problem whenwet. If you get rained on or you get wet incloud, get on bar and fly until the gliderhas 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 spiralor 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.
Tat 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 haveinstruments you can rely on, and need to believe
what they tell you (its 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. Ive emerged from cloudconvinced 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
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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 f lat 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 forthe 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. Ifthat 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 ascloud 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 EDGE
Staying 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?
Wheres the sweet spot, wheres the danger zone?
Kelly:Te 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 youcan 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 verygood 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 dont 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 theUK (where it is, according to the NAC, legal), and
have come to the conclusion that it really doesnt
help with XC flying unless the distance between
clouds is beyond glide-range, and even then its
marginal. Te 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 vulturestowards a cloud once, and watchedthem go straight under the dome ofthe cloudsuck, and straight up intocloud. Never seen birds do that before.I was a little behind and below so Iheaded for the edge of the cloud, andI could see by the ground shadow thatI was only a few hundred metres fromthe edge. Didnt make it. Got suckedin. Picked a compass direction andheaded that way, steadily climbing at4m/s with Big Ears and half bar star-ing at the compass. Fifteen minuteslater I emerged into a cloud-canyon,some 900m higher than I had gonein, having done 12km in a straightline. I surfed down the canyon in theclouds and popped out into the bluevery relieved. When I looked back thatcloud had gone from the little roundcumulus Id followed the birds into to amassive CuNimb. I glided straight onuntil I landed, then sat and watched the
lightning show. Adrian Thomas