To the traveller on the desert
coast of Chile and Peru it is a source of constant surprise that the sky is
so often overcast and the ports hidden by fog, while on every hand there are
clear evidences of extreme aridity. The big desert tracts lie east of the
coast range and there, except for slight summer cloudiness, cloudless skies
are the rule. The littoral is in many parts only a narrow fringe quite
unlike the real desert beyond. The fog bank overhanging it forms over the
Humboldt current and the upwelling cold water between the current and the
shore, drifts landward with the onshore wind, and gathers on the seaward
slopes of the coastal hills as the inf lowing air ascends them in its
journey eastwards. Sometimes it lies as fog on the surface; more frequently
it is cloud that hangs some distance above. On many parts of the coast its
characteristic position is from 2,000 to 4,000 ft above sea level. In Peru
the coastal fog is known as Garua, in Chile as Camanchaca.
There is much variation from
place to place in the position and habits of the fog. It is characteristic
of Antofagasta during the winter season; by contrast it is largely
absent at Iquique. On the coast at Caldera, the principal port
of the valley of Copiapo, the fog hangs over the hills and bay a good
part of the time. Paposo has a little pasture supported chiefly by
the coast fog. Where the hills of the coastal range are high or there is a
convergence of slopes toward a central point, the fog may thicken to an
actual drizzle and determine the location of a settlement. The fog bank is
thickest from June to September, and in that period the sun may be hidden
for weeks at a time except for occasional glimpses through the fog or at
sunset when it peeps from beneath the cloud cover before disappearing below
the horizon. There may be said to be a cloudless season in the southern
summer from November to April.
The fog sweeps up the valley
in the small draws of the coast range that slope directly down to the
Pacific. Further inland where the valley is more or less enclosed by the
surrounding hills, the fog settles down from aloft as night comes on and in
the morning the whole valley may be filled with it. It is indeed a strange
experience to be in the midst of desert country and yet awake in the morning
to find the air filled with a clammy, cold, fog. It does not long survive
the morning sun, and after a few hours of daylight the edge of it may be
seen retreating up the slopes to the crests of the coastal hills. Riding
northward through the coastal desert towards the Huasco valley,
Darwin in 1835 observed the belt of fog from elevated points along the trail
and wrote: “During the winter months, both in northern Chile and Peru, a
uniform bank of clouds hangs, at no great height, over the Pacific. From the
mountains we had a very striking view of this white and brilliant
aerial-field, which sent arms up the valleys, leaving islands and
promontories as the sea does in Tierra del Fuego”.
Among the native inhabitants
the Changos are the only ones that seem to have had a regular dependence
upon the resources of the coast in the belt of mist on the coast of Chile.
They are a tribe of Indians, primitive fisher folk of the desert coast; the
Spanish writer Lozano Machca stated in 1581 that there were 400 Indian
fisherfolk in the Bay of Atacama (Cobija). They depended largely upon
the sea for their living. They were necessarily nomadic, with canoes of
sealskin. One of their chief settlements was Paposo, situated where the
configuration of the coast appears to lead to an unusual amount of fog and
likewise of vegetation. Philippi himself found the seaward slopes about
Paposo at elevations of 500-1,800 feet enriched with vegetation during nine
months of the year.
