These Clouds Only Predictably Form in Australia

While all clouds are categorized based on the type, there are not many clouds that are named. Australia is home to two of these named clouds: Morning Glory clouds and Hector. Learn about these two very different types of clouds that predictably form in Australia.

Morning Glory Clouds

Created by undular bores, Morning Glory clouds are long tubular formations that can stretch up to a 1,000 kilometers in length.  A type of roll cloud, similar formations have been spotted around the world but the area around Burketown in Queensland Australia is the only place in the world where the formation of Morning Glory clouds can be predicted.

Each spring (from late September to early November), this rare and unique cloud formation appears in the southern part of the Gulf of Carpentaria in Northern Australia and is visible from Burketown.  

The altitude at which these clouds form can range from a few hundred meters high to up to two kilometers up in the atmosphere.

Map of the Gulf of Carpentaria in Australia

Morning glory clouds from the ground

These Morning Glory clouds were captured by Mick Petroff in 2009 flying near the Gulf of Carpentaria, Australia.

How do Morning Glory Clouds Form?

This graphic provides a simplistic view of how Morning Glory clouds form.  These long, tubular cloud formations occur when a cold front or sea breeze creates a sudden temperature inversion, where a layer of cooler air is trapped beneath a warmer, moist air mass. As the cooler air pushes under the warmer air, it creates a rolling wave effect in the atmosphere, much like the bow wave of a boat.

This undular bore lifts the moist air, causing it to cool and condense into clouds at the wave peaks. As the wave propagates, it continuously forms new clouds at the leading edge while the trailing edge clouds dissipate, creating the illusion of a cloud rolling across the sky. The Morning Glory cloud, often extending from horizon to horizon, is most visible at dawn when conditions are just right, making it a breathtaking and unique atmospheric event.

This continual cycle results in the Morning Glory cloud formation.

For more detail, you can learn about how Morning Glory clouds are formed:

• The Morning Glory: Flow visualization by Mother Nature
• Morning Glory Clouds Video

Hector the Convector

Another predictable cloud formation that occurs in Australia has the nickname “Hector the Convector“. Every afternoon at around 3pm from about September through March, a cumulonimbus thundercloud develops over Melville and Bathurst islands that make up the Tiwi Islands in Australia’s Northern Territory.

Moist tropical air, sea breeze caused by the differential heating between the islands and the ocean, and the pyramid shape of the islands all contribute to this meteorological phenomenon. Sea breeze air moving between where the two islands meet forms the thunderstorm cloud.

Hector can reach up to 20 kilometers high.

References

Crook, N. A. (2001). Understanding Hector: The dynamics of island thunderstorms. Monthly weather review, 129(6), 1550-1563.

Meet Hector, the thunderstorm that can tell time. (2020, September 19). Scientific Scribbles – The University of Melbourne. https://blogs.unimelb.edu.au/sciencecommunication/2020/09/19/meet-hector-the-thunderstorm-that-can-tell-time/

See Also

• Cloud Streets
• What are Actinoform Clouds?
• What Causes Gaps in the Clouds?
• Clouds