On August 22nd, 2017 we learned about

Meteorological simulations suggest small amounts of snowfall each night on Mars

In 2008, the Phoenix lander spotted some unexpected weather on Mars. On a planet noted for red rocks and swirling dust storms, the lander caught a glimpse of dark clouds and bits of falling ice crystals blowing through the air. New data and detailed simulations are suggesting that that flurry wasn’t actually all that rare. The Red Planet likely gets a touch of snowfall each night thanks to some very cold winds, although not enough that the Curiosity rover will ever need a snowplow or snow chains.

The snow seen in 2008 was thought to be a bit of an outlier at first. There’s lots of evidence that Mars once had more liquid water on its surface, and that a fair amount of that water circulated in the skies as rain and snow. However, the latest data from the Mars Global Surveyor and Mars Reconnaissance Orbiter suggest that some snow may fall every night, because there’s still enough ice in the atmosphere waiting to be blown to the ground.

Nippy at night

Mars’ thinner atmosphere loses a lot of heat at night, causing clouds to drop rather quickly. Any warmer air on the planet’s surface would rise up, and the competing activity would make for some strong winds, possibly blowing around 22 miles per hour. These gusts would then collect and blast ice crystals from the upper atmosphere down to the ground as microbursts, like miniature blizzards in the dark.

New data is not showing any kind of accumulation of snow pack, which isn’t surprising. While there are apparently just enough ice crystals in the Martian atmosphere to make a microburst, most of them seem to sublimate before they hit the ground. This doesn’t mean that this weather report isn’t significant to mission planners though. Even if future spacecraft or astronauts don’t need to worry about serious snowfall, the nightly gusts of wind that blow the ice around may be strong enough to warrant special consideration to avoid damaged equipment or complicated landings.

Source: We Have First-Ever Evidence That Mars Gets Intense Snowstorms in The Dead of Night by Peter Dockrill, Science Alert

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