A strange formation of clouds was seen in the heavens of Sydney, Australia on Friday. The odd pattern was dubbed a”cloud tsunami,” which both frightened and stunned the citizens of New South Wales. Technically a “shelf cloud,” those on Bondi Beach saw what appeared to be a massive, several-kilometer-long wave stretching across the sky.

What is a shelf cloud?

The shelf cloud is created by a cold outflow from a thunderstorm lifting the moist air very abruptly, it is an outflow feature from a thunderstorm. When the rain from the thunderstorm comes vertically down it drags the air with it, it spreads horizontally and forms a gust front, you get the humid air being lifted abruptly from the outflow of the thunderstorm.

The pictures and videos of the once-in-a-lifetime incident emerged online. Have a look!

See the pictures here:

It is absolutely breathtaking!

It looks Scary!

There’s a GIF image too….!

In these amazing photos you can see a huge squall approaching Sydney. The ominous cloud looks like some kind of terrifying tsunami.

Watch the shelf cloud video here:

The Hunter and Central Coast regions then announced severe thunderstorms that produced large hailstones and heavy rainfall, which were predicted to result in flash floods and strong, damaging winds. Forecasters started to worry when storms started to submerge the south of Sydney near Camden.