Persistent dust cloud activity on Mars near Echus Chasma in 1978

The Echus Chasma clouds of Mars, which are the first to be observed by spacecraft in the equatorial canyon region of the planet, extend the geographic and seasonal ranges in which dust stoms are known to occur. Viking camera observations of these clouds in red and violet filters are presently noted to imply their composition to be partly dust and partly condensate. Drainage winds, part of a diurnal wind system driven by thermal and elevation contrasts, are seen as a plausible interpretation of the observed phenomena.