Did You Really See That?
by Cyndy Hall
Tricks of the Desert
Imagine that you're a thirsty traveler crossing the Sahara. It's been three days since you've seen anything but sand, scorpions, and camels. But wait a minute. Do you see that lake? It's glistening, icy-cool…
Look again. That big blue puddle is probably a mirage, one of several tricks the Sahara plays on weary travelers. A mirage is a sight that looks real but isn't really there. In the desert, mirages look like water in an oasis (a patch of fertile land surrounding an underground spring). The image is “bounced” across the desert on top of dense waves of scorching hot air. Hundreds of real oases dot the Sahara, but don't be fooled: Most are much farther away than what you see in the sizzling air “mirror” of a mirage.
During the dry winter season, harmattans (sandstorms) are a frequent, dangerous Sahara phenomenon. Warned by the eerie moans of the rising wind, travelers quickly tie up their camels and hide under blankets. Within minutes, a dusky-brown cloud blots out the Sun. Winds clocked at more than 100 miles per hour whip the desert sand into blinding, deadly swirls that can last for hours—or days.
After a harmattan, an experienced Sahara traveler will brush off the gritty sand, then carefully shake everything. Why? Because scorpions seek out warm, dark places during sandstorms—especially blankets, boots, and clothing. Watch out the next time you're in a harmattan!
- What weather event often occurs during the winter in the Sahara desert?
[anno: A harmattan or sandstorm often occurs during the winter in the Sahara desert.]
- How have people adapted to this weather event?
[anno: People have learned to know when a sandstorm is coming by listening for the moaning sound the wind makes. They tie up camels and hide under blankets to protect themselves.]
- What weather instrument might you use to measure this event?
[anno: Answers may vary but could include that the student would use an anemometer to see how fast the wind is blowing. Students might also answer that they would use weathervanes to see which direction the wind was blowing.]