Weather on Mars: Snow Might Hit Red Planet in Nighttime Storms

mars
A view of the Noctis Labyrinthus region of Mars, perched high on the Tharsis rise in the upper reaches of the Valles Marineris canyon system. Reuters/NASA/JPL/University of Arizona

If, as humans have long imagined, we end up colonizing Mars one day, kids everywhere can breathe a sigh of relief—the magic of a snow day might still be possible. 

A new study published this week by Nature found that the Red Planet might be subject to nighttime snowstorms. The researchers used a "combination of computer meteorological models and observations" to "carry out sophisticated computer simulations to evidence that strong winds and fast precipitation of water-ice particles is occurring in Martian nights in so-called snowstorms," the lead author of the study, Dr. Aymeric Spiga, told Newsweek in an email.

The study helps explain NASA's Phoenix Mars lander detected snow nearly a decade ago. "We'll be looking for signs that the snow may even reach the ground," Jim Whiteway, the lead scientist for the meteorological station on the Phoenix lander, said at the time.

Spiga, who researches astrophysics, geophysics and meteorology at the Université Pierre and Marie Curie, in Paris, France, said that the snow can reach the ground. However, it's an icy product that might not accumulate in the way we often experience snowstorms on Earth.

"Snowstorms on Mars are much less dangerous than they are on Earth, and the quantity of snow that is precipitating is also quite small," Spiga said in an email. "So if snow precipitation is able to reach the surface (which is not the case for all snowstorms), that'll look like thin patchy frost, rather than thick snow deck as it is on Earth. And, last but not least, on Mars the snow particles are very tiny ice crystals (a couples micrometers/tens of micrometers) while on the Earth you can have snow made of much larger (and complex) snowflakes."

Still, the storms on Mars do resemble phenomena we see on Earth in some ways. Spiga said the team had another name for the snowstorms—ice microbursts—a term derived from traditional terrestrial meteorology that refers to a "localized column of sinking air (downdraft) within a thunderstorm," as defined by the National Weather Service.

But the Mars phenomenon, as Spiga and colleagues discuss in their study, published on Monday in Nature Geoscience, is strictly a nighttime affair. Water-ice particles in Martian clouds emit infrared light at night very efficiently, says Spiga, cooling the local atmosphere. That cooling creates a cold layer of air on top of a warmer layer of air. (During the day clouds absorb light, which prevents snowstorms.) The difference between these layers sparks convection—heat or moisture moving vertically through the atmosphere—along with strong winds and mixing. The end result? Martian snow. Just maybe not enough to close schools.