“Waterfall of Light” Appears Over Beijing as Sunbeams Break Through the Clouds

A striking light display appeared over Beijing on Sept. 27, as shafts of sunlight broke through gaps in thick cloud cover and streamed toward the ground, creating what many viewers described as a spectacular “waterfall of light” across the city skyline.

Photos and videos of the scene quickly attracted attention online. In the images, dense clouds covered large parts of the sky while narrow openings allowed sunlight to pass through, producing bright, well-defined beams that appeared to stretch from the clouds toward the city below.

The dramatic effect changed continuously as the clouds moved and the angle of the sunlight shifted.

A natural combination of clouds, sunlight and scattering

The phenomenon is commonly described online in China as a “Tyndall light” effect. Scientifically, however, the visible beams are more closely associated withcrepuscular rays, or shafts of sunlight that become visible when they pass through gaps in clouds.

Sunlight itself is normally invisible as it travels through clear air. But when light encounters tiny particles and droplets suspended in the atmosphere, some of the light is scattered in different directions. This scattering allows observers on the ground to see the path of the sunlight.

When thick clouds block most of the sun while leaving several gaps, the resulting beams can appear particularly dramatic.

A similar scene was reported in Beijing in early August after a rain shower, when sunlight broke through layers of cumulus clouds and produced golden beams above the city's historic architecture.

Why does it look like light is falling from the sky?

The “waterfall” appearance is largely a visual effect created by the interaction of light and clouds.

Clouds act as a natural screen, blocking much of the sunlight. Where openings occur, sunlight passes through in concentrated sections. Atmospheric particles then scatter some of that light, making the otherwise invisible light path visible from the ground.

If the gaps in the clouds are narrow and the sunlight reaches the atmosphere at a favorable angle, several beams can appear to fan out or run almost parallel.

From the perspective of someone standing on the ground, the effect can look as if enormous columns of light are descending from the sky.

The phenomenon is also sometimes called “crepuscular rays” or, more poetically, “God rays.”

Autumn weather provides a changing canvas

Beijing's weather has been transitioning into the cooler part of the year, with recent forecasts indicating periods of increased cloud cover and occasional rain. Meteorological conditions such as cloud thickness, humidity and atmospheric particles can all influence how clearly sunlight beams become visible.

The right combination is relatively specific.

Clouds that are too thin may allow sunlight to spread evenly across the sky, while clouds that completely block the sun leave no visible beams. A combination of substantial cloud cover, openings in the clouds and an appropriate solar angle can create the dramatic shafts of light seen over Beijing.

That also explains why the phenomenon can disappear almost as quickly as it appears.

A fleeting spectacle over the city

For residents surrounded by buildings, roads and skyscrapers, such atmospheric phenomena can be especially striking.

The city's architecture provides a visual reference for the enormous beams of light, making the contrast between the dark clouds and illuminated sky even more dramatic.

Beijing has seen several eye-catching atmospheric displays this year. In July, a large double rainbow appeared over northern parts of the city after a rain shower, drawing widespread attention.

This time, however, the spotlight belonged to the sunlight itself.

Unlike a rainbow, which produces a familiar spectrum of colors, the latest display was dominated by golden and pale-white beams cutting through darker clouds.

The shape and intensity of the rays changed from minute to minute, making each photograph slightly different.

For many people who happened to look up at the right moment, the effect was a reminder that even an ordinary day in a major city can produce an extraordinary natural scene.

As clouds drifted across the Beijing sky, the “waterfall of light” gradually faded — leaving behind a brief but memorable display created simply by sunlight, clouds and the atmosphere.