I have been begging my friend to send me these pictures for weeks. He took them on his cell phone on is way to the desert. Take a look how a sand storm progresses.

1) Storm brewing in the Horizon

2)  Slowly making its way across the desert, getting bigger. (Notice the family taking a picnic in the background)

3) Storm engulfs the unsuspecting families out enjoying a desert picnic

4) Storm thickens and grounds all traffic to a standstill. Visibility is ~0.

5) Taken from inside the car, it is pitch black outside during mid day. The darkness lasted 20 minutes before visibility was restored.