Heat storm

"It is always folly to run from a heat storm. Even a Jedi has no way to fight it."

A heat storm was a natural occurrence that frequently raged across Ryloth's sun-baked day side. Brought about due to Ryloth's rotational axis being roughly parallel to its plane of orbit, heat storms consisted of furious cyclonic winds reaching speeds of up to 500 kilometers per hour and temperatures upwards of 300 degrees centigrade as they raged across Ryloth's Bright Lands, searing everything in their path before eventually dying out on the planet's night side. If anyone was caught in one, they would be incinerated.

Many cities on Ryloth were protected from these storms by encasing themselves underground, although particularly bad heat storms could make even caves near the surface temporarily uninhabitable. Twi'lek siren whistles were used to warn populations of approaching storms.

In the city of Kala'uun, mothers of Twi'lek children told a tale of two young lovers, Ko'lek and Oo'rha, whose lovestruck wanderings led them right into the path of a heat storm that killed them as they lay in each other's arms. The story was intended to discourage children from wandering in unknown tunnels beneath Ryloth's surface.

In 3,986 BBY, the Twi'lek Jedi Tott Doneeta attempted to use the Force to wrangle a heat storm that sprang up to threaten an exiled clan under his protection while they moved amongst the mountains in search for a new home. As a result, he received severe burns to the left side of his face.