Lucky climbers on Western Australia's Bluff Knoll rewarded with rare 'cloud waterfall' sighting

Pure white clouds flowing down a towering mountain, lit by a glowing morning sun.

That was the view that greeted two climbers as they took on Bluff Knoll, the tallest peak of Western Australia's Stirling Range.

It takes a combination of high landscapes and unique weather conditions to create an incredible "cloud waterfall", a phenomenon that has appeared here twice in recent weeks to the joy of hikers and photographers who were lucky enough to witness it.

So what is it that causes this effect, and what should you be looking out for if you want to catch it?

Not too hot, not too low

There isn't a proper term for it, but essentially a "cloud waterfall" is a large body of fog which forms at the top of a peak and sinks downwards as it moves over the edge.

While fog feels like cool air to us, it is dense enough to act similar to a liquid, causing the flowing effect that resembles a waterfall.

It’s a more common event than one might think, but it does require the perfect mix of conditions and location, according to Bureau of Meteorology senior forecaster Jessica Lingard.

"Nice clear skies at night, not much wind, nice cool conditions allowing that fog to form and you need the topography element as well," she said.

Then there is the third key ingredient: the dedication to be up and out at these peaks to see it happen in person – usually in the early hours of the day.

"You have to be in the right spot at the right time to capture such beautiful events,” Ms Lingard said.

Cloud waterfalls can be found in many parts of Australia and are often seen on sea cliffs.

While it looks immense and perhaps even daunting, if you found yourself inside one of these cloud waterfalls, it wouldn’t feel too different from being out on your typical foggy morning.

“It would probably feel very similar, maybe just with a light breeze element as well, as you get that sort of flowing motion of the fog moving around,” Ms Lingard said.

Magic moment captured on camera

Photographer and videographer Thomas Allen managed to capture the cloud waterfall on camera at Bluff Knoll in January.

It's one of the most common sites in WA to see the weather phenomenon, but the peak also attracts many for its glorious views of the Great Southern landscape. 

It was simply a matter of luck for Mr Allen and his partner Danielle who were just aiming to catch sunrise at the top of the peak.

They didn't get quite what they were looking for, but they did get something better.

"Unfortunately we were a little bit late, but then we saw the cloud roll in and when we got near the top it started blowing down the mountains," Mr Allen said.

"Then it started flying over the mountains."

The Goreng-Noongar name for the Stirling Range is Koi Kyenunu-ruff, which means "places of mist moving around mountains", aptly describing the scientific processes behind the cloud.

"It was amazing, I've never seen anything like that as it flowed down the mountain," Mr Allen said..