melts more slowly.

However, mountains, because of their elevation, are exposed
to the sweep of violent winds which not only blow the snow in
considerable quantities to lower levels, where the temperature
is higher, but also dissipate and evaporate the snow to a
wasteful degree. The southern slopes, also, are so tilted as
to be more completely exposed to the direct rays of the sun,
and in the Sierra Nevada and probably elsewhere are subjected
to the persistent action of the prevailing southwest wind.

On the other hand, the mountain mass, by breaking the force of
the wind, causes much of the drifting snow to pile up on
its lee slope and at the base of its cliffs, where it finds
comparative shelter from the wind and sun.

Forests, also, conserve the snow. In wind-swept regions, they
break the force of the wind, catching the snow and holding it
in position even on the windward slopes of the mountains. On
the lower slopes, where the wind is less violent, the forests
catch the falling snow directly in proportion to their
openness, but conserve it after it has fallen directly in
proportion to their density. This phenomenon is due to the
crowns of the trees, which catch the falling snow and expose
it to rapid evaporation in the open air but likewise shut out
the sun and wind from the snow that has succeeded in passing
through the forest crowns to the ground. Both mountains
and forests, therefore, are to a certain extent wasters of
snow--the mountains because they are partially exposed to
sun and wind; the trees, because they catch a portion of
the falling snow on their branches and expose it to rapid
disintegration. However, the mountains by their mass and
elevation conserve immeasurably more snow than they waste, and
forested areas conserve far more snow than unforested. If the
unforested mountain slopes can be covered with timber, much
of the waste now occurring on them can be prevented, and by
thinning the denser forests the source of waste in them also
can be checked.

The experiences met with by the voluntary band of observers to secure
the data needed in their work are romantic in the extreme. An average
winter trip requires from a day and a half to two days and a half
from Reno. From the base of the mountain the ascent must be made on
snow-shoes. When work first began there w