Travel
If staying put on Antarctic sea ice is fraught with peril, traveling across it
is even more so. For not only are your chances of suffering frostbite or
getting lost in a whiteout or dying from hypothermia even greater, but you also
have to cope with extremely treacherous ice conditions. As the
Shackleton expedition's forays over the Weddell Sea ice showed,
traveling over pressure ridges - places where colliding floes have tossed up
massive slabs of sea ice - is challenging if not impossible. In addition,
cracks can appear without warning, weak bridges of ice can form over unseen
leads, and sea ice begins to break apart when the seawater temperature rises
above 28.5°F or even in strong wind or swells.
Seawater immediately beneath sea ice is roughly the same temperature as the
ice, or about 28.5°F. If you fall in, at the least you may have your
breath knocked out of you, or you may involuntarily lurch into a spastic fetal
position and lose control of your muscles. If unprotected by survival gear, you
would be able to swim at most a mile before the coldness utterly incapacitated
you. If you stayed put where you fell in, you'd lose consciousness in five to
seven minutes and, if you didn't drown right away, you'd freeze to death in ten
to 30 minutes.