A heat storm as it appeared in 4 ABY
A heat storm represented a common natural disaster that frequently swept across the sun-drenched day side of Ryloth. These storms arose because Ryloth's axis of rotation was nearly parallel with its orbital plane. Heat storms involved powerful, swirling winds that could reach speeds as high as 500 kilometers per hour, coupled with temperatures exceeding 300 degrees Celsius. They would tear across Ryloth's Bright Lands, incinerating everything in their path, before finally dissipating on the planet's night side. Anyone unfortunate enough to be caught in one would be burned to ash.
Clone troopers confronting a heat storm on Ryloth during the era of the Clone Wars
Many cities located on Ryloth implemented protective measures against these storms by building their structures underground. However, particularly severe heat storms could render even subsurface caves temporarily uninhabitable. Twi'lek siren whistles were used as a warning system, alerting the population to the imminent arrival of these dangerous storms.
Within the city of Kala'uun, Twi'lek mothers would tell their children a cautionary story. It involved two young lovers, Ko'lek and Oo'rha, whose romantic wanderings led them directly into the path of a heat storm. They perished in each other's arms as a result. The purpose of this tale was to dissuade children from exploring the unfamiliar tunnels beneath Ryloth's surface.
In 3986 BBY, the Twi'lek Jedi Tott Doneeta attempted to use the Force to control a heat storm. The storm had arisen and threatened an exiled clan under his protection as they moved through the mountains in search of a new place to live. As a direct consequence of this attempt, he suffered severe burns on the left side of his face.