KRONFELD ON GLIDING AND SOARING.pdf - Lakes Gliding Club

CLOUD AND THUNDERSTORM SOARING 211
lying far beneath them, and the phenomena we generally
describe as gusts are found to be mainly due to the influence
of a passing cloud. At the moment when such a cloud
passes above us the area of upwinds suddenly increases and
we climb high, only to drop again as soon as it has passed.
But if we obtained in this way only a slight increase in
height without coming under the direct influence of the
clouds, the phenomenon would still be of use to us. It
would always be an important aid to us when we have to
cross gaps in slope soaring. Even if we could not quite
get away from the upwind on a slope, our chances of reaching
an opposite slope would be greatly increased if a cloud
chanced to be standing directly over the intervening space
or if, by the help of a cloud, we could gain the additional
height that would enable us to push across the difficult spot.
But this is not what we mean by cloud soaring in the true
sense of the word. Just as slope soaring is soaring by means
of the upwind above a slope (which wind alone bears us up),
so true cloud soaring must be soaring in the upwind under
a cloud, without any dependence upon slopes. The slope
would only be used as a kind of jumping-off ground to
enable us to pass across to the cloud. The first and most
difficult thing to learn is how to achieve contact with the
clouds.
Hitherto we have had to deal with stationary upwind
areas, that is to say, areas that are always to be found at the
same locality on a mountain slope as long as the wind blows
from a certain quarter. They are local, and may be described
as fixed. The upwind area of the clouds is a wandering
one ; like them, it drifts over the land. Our task is to
cross from the fixed to the wandering. As we spring from
the firm ground on to a moving tram, so must we spring
from a slope to a passing cloud.
Looking at the business in hand from the point of view
of the plane, we are concerned with two directions of movement
that of our machine, which, generally, like the
position of the slope, lies athwart the direction of the wind,
and that of the clouds, which is identical with that of the
wind.
Cloud soaring is still a very young sport, but already we