1. Seacoast	2. Swamp	3. Forest	4. Plains	5. Desert
6. Hills	7. Mountains	Hierarchy of Terrain	Bodies of Water	WSG

    Not all deserts are covered with sand, and not all of them are in hot climates, but every desert has one thing in common with all the others: They are very, very dry.
The technical definition of a desert is any AREA that receives less than 10 inches of rain per year; in actuality, the yearly rainfall in most deserts might be half of that amount or even less.

    The lack of moisture in a desert does not render the AREA totally barren or uninhabitable.
Many plants & animals are naturally able to cope with a severe shortage of water;
the cactus and the camel are perhaps the best-known examples.
However,
characters are not so fortunate;
they need water frequently and in fairly large amounts,
and the best way to satisfy this need during a trek across the desert is to carry a supply of drinking water (or the means to produce water magically).
Although it is possible to find water in the desert, either by stumbling across an oasis or by digging for ground water,
neither of these methods is especially reliable.

    Most deserts are composed of {dry}, hard-packed earth beneath
a layer of gravel, with the terrain occasionally broken by a clump
of large boulders. Water can be particularly difficult to find in this
kind of desert terrain, because the rainfall tends to run off the surface
(flowing toward a place of lower elevation) instead of soaking
into the ground. Relatively few deserts are covered with sand,
which does permit water to soak into the terrain from where it can
be recovered later.

The icy wastes of the polar regions can also be considered deserts.
In a desolate place such as the arctic north, vegetation and
animal life are even more scarce than in a desert located in a hot
climate. Although moisture is abundant on the ground (in the
form of ice), the terrain still qualifies as desert because it receives
very little precipitation.

On a sandy desert, dunes are formed by the action of the wind;
their shape and size depend upon the amount of sand and the velocity
of the wind that moves it around. Where sand is abundant
and the wind is at least occasionally very strong, dunes can grow
to be more than 500 feet high. The slope gradually ascends in the
direction of the wind. From the peak of the dune, the sand slopes
down sharply on the side opposite the wind direction. In a very active
wind, the peak of a dune can move several hundred feet in
only a day or two; as windblown sand cascades down the slope
away from the wind, that side of the dune becomes able to support
more and more sand, and eventually the dune peaks at a
point farther downwind. Where the supply of sand is smaller and
the wind is less intense, dunes are correspondingly smaller and
shorter. In fact, the technical definition of “dune” is an accumulation
of sand, formed by wind action, that is no more than 70 feet
high. Anything larger is properly called a sand mountain, or
“draa.”

An object (or a character) that remains in one spot for any great
length of time in a desert with heavy sand cover may end up buried
under tons of sand. On the other hand, the action of the shifting
sands may uncover the entrance to the hidden temple that
you’ve been searching for. . . .

<examples:
arctic:
subarctic:
temperate: Gobi desert
subtropical:
tropical:>