Visibility
Antarctic weather can change in an instant, with a perfectly
sunny day transmogrifying into a blizzard that lasts three to
five days and packs winds of up to 90 mph. Visibility can be
severely impaired even on clear days. With sunlight reflecting
and refracting off snow, ice, and water, whiteout can occur.
You suddenly lose all sense of size and shape, and your depth
perception disappears. What you think is a building in the
distance might be a small box at your feet. With no shadows or
other non-white features to guide you, you might stumble as
you walk because you can't distinguish between horizontal and
vertical.
Whiteout is particularly hazardous to pilots, who can become
disoriented without landmarks, shadows, or a horizon to guide
them. In 1955, a helicopter on a scientific mission in
Antarctica crashed full speed into an ice sheet and tumbled
for over 70 yards before coming to a halt. A second helicopter
rescued the downed pilot and started to fly back to a waiting
ship. Realizing he was in a whiteout and keeping his eyes on
what he thought was the horizon, the second pilot suddenly
felt a jolt: the helicopter had slammed into the ice shelf.
Fortunately, it bounced off on its pontoons, and the
helicopter returned safely, though the first pilot died of his
injuries a few hours later.
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