142/162
400 4F_11319.4.enu
Snow forms from water droplets in the atmosphere at temper-
atures of at least –4°C.
Ice crystals
in widely varying shapes form:
Hailstones
are snow crystals enlarged by the adhesion of ice;
they are usually spherical or tapered in shape
.
Hoarfrost or rime
forms from water vapour or precipitation
on chilled objects (fences, bushes, surface of snow).
White frost develops when the wind carries chilled droplets of
water onto solid objects.
Fresh snow
initially forms an airy structure of loosely inter-
meshed snowflakes.
The original shapes soon disappear, however, and the indi-
vidual flakes are no longer recognisable only a few days after
falling.
Over and above these changes, which take place naturally and
cannot be influenced (they are caused by wind pressure,
freezing and evaporation producing a loss in volume, whereas
differences in the temperature of the air trapped close to the
ground and the external air tend to produce an increase in
volume), it is important to bear the following in mind:
Always work so as to cause as little damage as possible to the
snow. The aggressive action of auxiliary equipment such as a
tiller damages the snow crystals; these damaged crystals have
lost their ability to mesh as a loose blanket, tending instead to
ball and form gritty snow (often at entrances to garages,
approaches to lifts, bottlenecks).
Preparing fresh-fallen snow
Fresh-fallen/powdery snow consists of crystals that are loosely
attached to each other and which therefore trap a great deal
of air. The process of preparation inevitably expels some of this
air and packs the crystals more tightly together. This gives the
surface layer of snow the ability to bear weight.
Snow as a medium
D
RIVING
TIPS
AND
INFORMATION
Summary of Contents for PistenBully 400 4F
Page 1: ...Operating Manual From WKU 824 11319 en Vehicle ...
Page 8: ... 8 162 400 4F_11319 4 enu NOTE ...
Page 14: ... 14 162 400 4F_11319 4 enu NOTE ...
Page 24: ... 24 162 400 4F_11319 4 enu NOTES ...
Page 32: ... 32 162 400 4F_11319 4 enu NOTES ...
Page 94: ... 94 162 400 4F_11319 4 enu NOTES ...
Page 100: ... 100 162 400 4F_11319 4 enu NOTES ...
Page 118: ... 118 162 400 4F_11319 4 enu NOTES ...
Page 140: ... 120 150 400 4F_11319 4 enu NOTES ...
Page 150: ... 150 162 400 4F_11319 4 enu NOTES ...
Page 163: ......
