Here is one cool thing ... one of the survival techniques ACTUALLY WORKS. Here in the low desert of Atacama, altitude 2200 feet, about 30 miles from the coast, there are dense fogs at night.

I spread out a tarp on the back of the Jeep to try to keep things dry. I weighted the tarp with rocks. I was amazed to discover the next morning ... pools of water at the locations of the rocks. There is so much condensation, you get real pools of water. I think that if you had about 5 tarps, each anput 20 foot square, it would be enough water for one person for one day.

First time ... i have seen this idea work under real conditions!!

WHY does the technique work here? The Atacama is an enormous desert, extremely dry. In many places there are no plants at all. Only gravel, sand and rocks. The convection of hot air is very strong. By noon, convection winds can be very strong ... enough to destroy a tarp because it flaps violently. By evening, the einds die fown. A heavy marine layer moves in, for regions of the desert within 30 miles of the coast. The fog is so heavy that it blots out all light, and there is much condensation. This condensation from the rain-fog produces the pools of water on tarps, if you spread them out to collect water.