People in the Mountains - Mountain Geography: Physical and Human Dimensions - page 527

of avalanche hazard; maintaining and developing protective forests to stabilize snow
above settlements and infrastructure; using a variety of snow fences and buffers to sta-
bilize snow in avalanche starting zones; building protective and deflecting walls and
snow-sheds where buildings and infrastructure are exposed; and strengthening struc-
tures to withstand the high impact pressures of avalanches (Fig. 10.20).
The vast effort made to understand avalanches, control them, mitigate their effects,
and sensitize and manage people is a testament to the importance of avalanches in the
life of people in the mountains. Snow avalanches remain a potent force in most high
mountain areas, especially the heavily used and populated areas in the Alps and west-
ern Cordillera of Canada and United States.
Meteorological Hazards
Severe weather conditions in the mountains can produce various hazardous and even
disastrous outcomes. In a general sense, these arise from extreme cold or heat, too
much or not enough rain/snow, strong winds, and lightning. The impacts of these haz-
ards on people, settlements, and land uses depend on diverse natural and human condi-
tions. Drought, for example, may occur locally at small scales, but is often a large-scale
phenomenon affecting not only mountains but surrounding regions as well. It usually
is manifest as reduced and/or irregular precipitation that often lead to reduced stream
and groundwater flow and reduced soil moisture, negatively impacting natural and hu-
man processes and conditions.
Drought conditions are particularly prevalent in interior basins and plateaus of trop-
ical mountains (e.g., the Altiplano of southern Peru and Bolivia), in semiarid and ar-
id mountains (e.g., the Karakoram; Fig. 10.11), those of a Mediterranean-type climate
on a seasonal basis, and in rainshadow valleys (e.g., interior valleys and basins of the
North American Cordillera). Lower than expected precipitation lessens agricultural and
livestock production, causing food shortages, and creates power deficits and water sup-
ply shortages. Reduced snowfall in winter may have similar effects as well as limiting
the snow-based recreation activities on which many mountain locations in Europe and
North America are dependent, although the shortages of natural snow are today com-
pensated to a certain degree by relying on artificial snowmaking. Besides impacting
local people, drought in the mountains may create disastrous water and energy short-
ages for people, agriculture, and industry outside the mountains. Drought generally is
caused by natural climatic variations but may be locally exacerbated by human activit-
ies (e.g., overutilization of soil and water resources, deforestation, water-demanding ag-
ricultural crops and techniques). The area around Mount Kenya in East Africa provides
an example. Mount Kenya, with its small remaining glaciers, rainfall, and snowfall, is a
water source for the semiarid surroundings. The traditional inhabitants of the southern
and western slopes are the agrarian Kikuyu people who held de facto or customary land
tenure rights prior to the British colonial period, which ended in 1963. Large areas of
land remained in the hands of British settlers and corporations, and much of this land
has been turned over to water-demanding commercial production of fresh vegetables
and flowers for export. Additional factors influencing risk in the area relate to available
land being designated within Mount Kenya National Park and demand for land rising
dramatically as a result of Kikuyu population growth and resettlement in-migration of