Geography Reference
In-Depth Information
it is clear that all settlements that experience the challenges of this season—even if
only occasionally—have to cope with several major problems, although these vary
in their severity.
The most obvious problem of winter cities is the
increased amounts of darkness
in winter, with short days and low angle sunlight. There are few settlements in the
far north of the northern hemisphere where the sun never rises for weeks or months
at a time, but some idea of the conditions can be seen from the fact that at 78ﾰN (mid
way between the Arctic Circle and the North Pole) there are 94 days without sun
between November 13th and February 15th. At the Arctic Circle the period between
these days has only 6 and 8 h of sunlight respectively, whilst the sun dips below the
horizon at the winter solstice on December 22nd. Hence Hammerfest (Norway) has
no sun above the horizon for two months at 70ﾰ39 N/23ﾰ.41 E, and claims the title
of the world's most northernmost town, although the small settlement of Huningss-
vag at 70ﾰ 58 N/25ﾰ58 E. is actually further north, as is Barrow in Alaska. Further
south, between 60-62ﾰN, the number of urban places increases and places such as
Anchorage, Oslo, Stockholm and St. Petersburg can count on over forty days with
less than 8 h of sunlight, although cloud cover can exacerbate the extent of the pe-
riods of darkness.
Obviously, winter in northern latitudes results in many days with
freezing condi-
tions.
Prolonged exposure to cold can be fatal, unless people are suitably clothed
to keep warm, with winds making conditions worse. Hypothermia occurs because
the body reduces blood supply to the extremities, such as fingers and toes, so they
get frostbite. If pain is felt, then the nerve endings are still sending messages to the
brain, but continued exposure leads to a numbness and then no feeling, which is
life-threatening, However the effects are not just physical since exposure is marked
by a slowing of activity and the ability to think, which is often indexed by what a
recent survey of the effects of cold called the 'umbles', where unprotected people
may experience the sequence of mumbling, fumbling, grumbling, stumbling, and
finally tumbling over and dying from too much cold (Streever
2009
).
The cold also means that precipitation comes in the form of
frost, snow and ice
,
all of which reduces the longevity of buildings, given the weight of the last two, and
the freeze-thaw effects between cold and warmer temperatures that widen cracks,
as well as hindering the comfort and especially mobility of the modern populations
in towns and cities. In addition, the threat of avalanches sliding down mountains
and burying settlements, or icebergs in the sea and shorelines, create additional
threats to roads, towns and shipping in such areas. In more northerly areas where
the ground is below 0ﾰC for over two years, the cold creates permafrost condi-
tions—essentially permanently frozen ground (Harris
1986
). The areas that are
affected are usually divided into four types—continuous, discontinuous, sporadic
and alpine permafrost zones. They occupy approximately 22 % of the land area of
the northern hemisphere, together with considerable areas under the Arctic seas. In
Canada the zone of permanent permafrost starts at 65ﾺN on the Alaska border, dip-
ping southwards to the southern shore of Hudson Bay at 55ﾺN, whilst the sporadic
zone runs from 53ﾰN on the Alberta-B.C border to the southern tip of James Bay
and to the southern edge of Labrador (Bone
2005
). The problem with permafrost
