We’ve seen them in a bunch of movies: massive storms in barren planets that may last for days, weeks or even months. Maybe the storm in Riddick (2013) does not qualify, but planetary storms in Soldier (1998) that forced people underground definitely do.
The question, this time, would be … are these storms even possible in planets with different atmospheres and weather conditions? And, yep, the answer is affirmative.
The Centre de Serveis Científics i Acadèmics de Catalunya (CESCA), and the computer services at the Institut de Ciències de l’Espai (ICE) have been working specifically on Saturn storms. For example, its North Pole hurricane is lasting for years and its eye alone is about half the length of Australia! When Cassini arrived at Saturn in 2004, the north of the planet was hidden in winter darkness, but when spring arrived in 2009, the hurricane revealed in all its glory. It is about 20 times larger than hurricanes on Earth and its winds are four times stronger than ours: around 530 Km/h.
And this is not all! Each year in Saturn (around 30 years on Earth), a gigantic storm known as the Great White Spot roams the planet. The first one was observed in 1876 (when the telephone was invented), and the last one in 2010, when Cassini was already there observing the planet. The thing started as a small brilliant white cloud on the northern hemisphere and expanded rapidly to cover thousands of millions of km2 during more than seven months. Cassini provided high resolution images of this Great White Spot.
Scientists at CESCA and ICE used this information to study and explain the storm origins this time. Apparently, its focus is high: around 300 km above the visible clouds. The storm brings moist gas all the way up to form visible clouds. The process releases large quantities of energy, that interacts violently with the usual Saturn wind, pumping it up to 500 km/h. Just like in Soldier, too.