Dust devils and dust storms
A tornado is a whirling wind that comes down from the sky and touches
the ground. Dust devils and sand pillars are whirling winds that go from
the ground up into the sky.
Whenever hot air rises, it causes a wind. On a hot, dusty prairie, or a
desert, rising hot air often begins to spin. Then, it carries up a
whirling cloud of dust or sand.
On a prairie, or on a dusty city street, these whirling clouds are
called dust devils. They never get very high. But in a desert they
sometimes go whirling up in a thick cloud a thousand feet (304 meters)
high. Then, they are often called sand pillars.
Sometimes, when a large mass of hot desert air rises up, the wind that
rushes in to take its place causes a sandstorm or dust storm. The wind
sends the sand rushing through the air. Great clouds of dust rise up,
turning the whole sky black. A desert storm can often blow for hours, or
even days.
