For a few days each February, the setting sun lights up the cascade with a bright orange illumination that makes it look like it's on fire.
It's hard for our brains to process the phenomenon as anything other than fire because there aren't enough contextual cues showing the same sunlight on other surfaces.
When you want to create weird and magical evening light effects in painting, it's good to keep this balance in mind: on the one hand, you want the light to be precious and rare, but it has to touch enough different surfaces to give it some context.
One artist who pulled this off beautifully is the American orientalist Frederick Arthur Bridgman. In this magical evening scene, the main subject is lit by a cool dusk twilight, which diminishes as the draped figures recede into the tree shadows.
He makes the bold choice not to show the source of the light itself, just its effect. The light effect really works because he was careful to set up large areas of mysterious darkness, softness, and shadow in the rest of the picture.
The painting is called "Fête of the Prophet at Oued-el-Kebir (Blidah), 1889.
See more paintings from this era at the blog Underpaintings.