What is the X in X-mas?
A strong wind that carries clouds of sand and dust through the air. Most of the particles in a sandstorm are between 0.08 and 1 mm (0.0032 and 0.04 inches) in size. Sandstorms usually are limited to within 3 m (10 ft) of the ground, rarely getting more than 15 m (49 ft) high. They develop in desert areas where loose sand can be stirred up by wind. Most sandstorms occur during the day when the Earth's surface heats up and dissipate at night as it cools.