Dan Spires wrote:
I still see it as dust/sand slippage, which could be brought about by at least 3 means:

simple dust buildup and collapse

collapse brought about by winds

collapse associated with moisture seepage weighting dust/sand particles to collapse

Alex writes:
I'll certainly agree with (1) and maybe with (2) with some modifications (i.e., the streaks do not correlate with prevailing wind directions like aeolian features on the leeside of many craters or wind tails of rocks at the surface); however, (3) is not needed. The observed features can be explained totally without introducing liquid water at all, which satisifies Occam's Razor. In my opinion, the "wet" model for the dark streaks is a solution in search of a problem.

Alex R. Blackwell
University of Hawaii