Mars gets fierce night-time snow storms, say scientists

There are snow storms during the night at the poles on Mars, according to a new study into weather on the red planet.

Low-lying Martian clouds were previously thought to gently snow upon the planet's plains, with the ice-water particles slowly sinking to the ground due to the planet's extremely thin atmosphere.

But findings reported in Nature Geoscience suggest that snowfall on the red planet is a far more tumultuous and aggressive event.

It says particles swirl in fierce storms and are deposited on the ground in a matter of minutes, unlike the hours snow storms can last for on our own planet.

Snowfalls on Mars contain much less water than on Earth - they dump heavily on the planet's surface and only occur at night, according to the scientists.

"It's not as if you could make a snowman or ski," said Aymeric Spiga, an expert on the dynamics of planetary atmospheres at Universite Pierre Curie in Paris.

A sidereal day on Mars - the length of time it takes for the planet to rotate once on its axis - is slightly longer than on Earth.

On Mars, a day lasts 24 hours, 37 minutes, and 22 seconds - compared to 23 hours, 56 minutes and 4.1 seconds on Earth.

"Standing on the surface of Mars you wouldn't see a thick blanket of snow - more like a generous layer of frost," said Dr Spiga.

Most of the red planet is just that: Red.

But NASA's Phoenix lander, a stationary robot which scraped below the dusty surface at the planet's poles, discovered water in 2008.

The robot also analysed the weather and showed how water-ice clouds cooled during the night, making them unstable.

"We have shown that the precipitation of snow below the clouds is transported by very violent, descending winds," said Dr Spiga.