More info re water ice on Mars

Above: A fresh, 6-meter-wide, 1.33-meter-deep crater on Mars photographed on Oct. 18, 2008, and again on Jan. 14, 2009, by Mars Reconnaissance Orbiter's HiRISE camera. The bright material is ice, which fades from Oct. to Jan. because of sublimation and obscuration by settling dust.

Meteorites recently striking Mars have exposed deposits of frozen water not far below the Martian surface. Pictures of the impact sites taken by NASA's Mars Reconnaissance Orbiter show that frozen water may be available to explorers of the Red Planet at lower latitudes than previously thought...

So far, the camera team has found bright ice exposed at five Martian sites with new craters that range in depth from approximately half a meter to 2.5 meters (1.5 feet to 8 feet). The craters did not exist in earlier images of the same sites. Bright patches darkened in the weeks following initial observations, as freshly exposed ice vaporized into the thin Martian atmosphere...

More info at the NASA website (whence also the image credit).