Aside
from the obvious—being places of beauty and wildlife and winter
play in the snow—mountains often cause rain to fall, hold much of
the world's fresh water supply, and help to create beaches.
Mountains
Cause Rain?
When
breezes carry moist air from the oceans inland, that moisture often
remains invisible, as water vapor. But if the air begins to cool as
it blows against mountains and is forced upward, the water vapor
forms drops, and now we can see it: it forms a cloud. If the air is
moist enough, and if it gets cool enough, the drops forming the cloud
become so large and heavy that they fall to the ground as rain,
sleet, hail, or snow (depending on conditions).
You
can see how often mountains cause rain by studying yearly
precipitation totals. The areas on the seaward side of mountain
ranges often enjoy much more rainfall per year than the otherwise
similar areas on the other side of those mountains. The moisture has
been forced out of the air on the seaward side of the mountains; by
the time it has reached the other side of the mountains, and begins
to sink and warm, there is often no more moisture for rainfall. These
dry areas are considered to be in the mountains' rain shadow.
Mountains
Hold Fresh Water?
Mountains
collect and hold much of the year's precipitation as snow and ice and
then release it during warmer—and usually drier—times of the
year.
Also,
because mountains cause a lot of rainfall as well as snowfall, they
are often dotted with freshwater lakes. This water tends to move
downhill in creeks and then gather into rivers.
In
semi-arid and arid regions, 70 to 90 percent of river flows come from
the mountains, and even in moister areas, 30 to 60 percent of
freshwater comes from mountains. All the major rivers in the world
have their headwaters in mountains. Half of all the people in the
world depend on mountain water for drinking, as a source of energy or
income, or for growing food. (I found all these incredible statistics
here.)
Mountains
help create beaches?
 |
| Sand grains are incredibly varied and surprisingly beautiful. |
As
the creeks and rivers flow downhill from mountains, they erode rocks
and carry particles of rock to the oceans. Whenever the rushing
rivers are forced to slow down, they dump a lot of the rock particles
they are carrying. This creates fertile, mineral-rich soil for
farming as well as beautiful sandy beaches.
Actually,
we humans get a lot of important ores and minerals from mining in
mountainous areas, and fossil hunters often benefit from erosion in
uplifted areas, too.
Celebrate
mountains!
You
can either head for the hills, drink a toast of tap water (which
probably originated in mountains somewhere), or browse through some
mountain loveliness here
or here or here.
Also
on this date:
Physicist Max Born's birthday 
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