The placid-looking clouds of Saturn are far from peaceful. In fact, they are constantly disturbed by winds clocked by Voyager 2 at up to 1600 kilometers per hour! Storms frequently swirl across the cloud belts and last for many months.
On December 1, 1994, Hubble Space Telescope captured a view of a rare storm generated by a rising bubble of warmer air from deep within the planet. This Saturnian "thunderhead" was about the size of the Earth. It was made up of ammonia ice crystals formed when the warm upwelling air froze in the upper altitudes of Saturn's outer atmosphere.
Probing the reasons why Saturn's atmosphere behaves the way it does will almost certainly give us insight into the inner workings of other gas giant planets in our solar system -- and perhaps any we find orbiting other stars.