re: OK
I've been following the thread discussing this on unmannedspaceflight.com as well as other sites and the suggestion has been made that these might in fact be gusts of wind driven by the difference in conditions between the base of the cliff, which is dark material, and the top, which is bright. It's been pointied out that with that much mass wasting going on the cliffs ought to be less steep than they are. Personally I think that rapidly sublimating pockets of CO2 just beneath the surface could also be an explanation, anyone have any other ideas?