Snow can get caught inside these winds and rapidly fall downward. The researchers said that such Martian snowfall is analogous to small, localized storms on Earth called microbursts, in which cold, dense air carrying snow or rain gets rapidly transported downward from a cloud.
Any snow landing on Mars would not last long. Once the sun rises, any water ice on the surface would turn to vapor, "unless it was in a very cloudy region or high latitudes," Spiga said.
If the clouds the snow falls from are more than about 1.2 miles (2 km) from the Martian surface, the snow might turn to vapor before it even hits the surface, Spiga added. "This is something observed on Earth sometimes, with something called virga — streaks of rain falling from the clouds can vaporize before reaching the surface," he said.
Martian snowstorms could explain previously unexplained signs of snow detected in 2008 by the laser scanner aboard NASA's Phoenix lander.
"We are able to explain two different mysterious and surprising observations with a single meteorological phenomenon — these snowstorms," Spiga said.
These findings suggest that the Martian atmosphere is more dynamic than previously thought. "Since you have these powerful winds, these are able to vigorously mix anything, such as heat, water, methane, ozone, dust," Spiga said. "We can now use this data to see what impact these winds have on, say, how water moved from one region to another on Mars in the present and past."
Future research will aim to get more glimpses of these Martian snowstorms, Spiga said. "We want to look all over Mars and see when they happen at night, and what seasons they occur and the effect they have on a global scale," he said.
The scientists detailed their findingsonline yesterday (Aug. 21) in the journal Nature Geoscience.
Follow Charles Q. Choi on Twitter @cqchoi. Follow us @Spacedotcom, Facebookand Google+. Original article on Space.com.