To risk derailing my own thread:

Most of my preparedness kit is around avoiding wind, rain etc. But in an emergency in the summer, when it's very hot, what's a good bet for shelter? Would a space blanket help reflect the suns heat away (better than just shade from a tarp?)

I think I read once about using two cotton sheets as layers of tarps - as one gets hot from the sun it creates a thermal current to draw air through to create a breeze? Any ideas, or has senility come early?