The natives of Kintan called the lava rivers in the Endless Wastes Rivers of Fire. Like most lava, these rivers reached temperatures around 1300°F to 2200°F, which heated up the air around it also. The black and hard soil around the river formed out of rock and glass.
In 30 BBY, the Jedi Quinlan Vos and Aayla Secura crossed a River of Fire on Kintan followed by Bok.