http://abcnews.go.com/wire/SciTech/reuters20030219_513.html

"Noting that Earth-type life can exist in such seemingly hostile environments as the Antarctic and in super-hot undersea vents, Rothschild said some algae on Earth could exist in communities within snow."

"In a resting state, those organisms can survive for long periods, "maybe like you see in Mars between the times that it snows," Rothschild said. "That's something that you could envision surviving in the sort of conditions you describe."

H2O snow was observed at the Viking 2 landing site for over 200 SOLS (Martian days). Where there is snow, there is water when conditions rise above the triple point of water.

BD