From one of the latest images from Spirit shows an asymmetric dust pattern in the crater "Bonneville". Which way is the prevailing winds and why do you think so. I pretty sure of the line the wind follows, but I'm not sure of which direction... http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040318a/07-JG-01-pan-A074R1_br.jpg http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040318a/07-JG-01-pan-A074R1_br2.jpg http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040318a/07-JG-01-pan-A074R1.jpg These links are for the same image, just in order of increasing size and resolution (second is 1MB, third is 9MB).. -Paul