K’gari’s Travelling Sand Dunes: How Sand Engulfs Forests

K’gari looks almost impossible: an island made largely of sand, yet covered in towering rainforest and dotted with freshwater lakes. Off Queensland’s coast in Australia, this remarkable landscape is constantly changing. Winds push loose sand inland, creating enormous dunes that can bury vegetation and even cross waterways.

Wind-driven sand reshapes K’gari’s landscape, where shifting dunes meet forest and vegetation.

Formerly known as Fraser Island, K’gari is the world’s largest sand island. Its combination of shifting dunes, ancient forests, and freshwater lakes helped earn it World Heritage status in 1992. What makes the island especially fascinating is that its sand is not simply a beach material—it is the foundation of an evolving ecosystem.

What Is K’gari?

K’gari lies off the coast of Queensland, stretching approximately 123 kilometres along the coast. It is the traditional name used by the Butchulla people, the island’s Traditional Owners. The Queensland Government formally reinstated the name on 7 June 2023, and the World Heritage property was officially renamed K’gari in 2025. The island contains coastal heath, wetlands, mangroves, freshwater lakes and subtropical rainforest. These habitats are connected by the same sandy landscape that continues to change under the influence of wind, waves and shifting sea levels.

First Image Credit: Flickr

An aerial perspective of K’gari, the world’s largest sand island, off the coast of Queensland, Australia.

Image Credit: Flickr

How Did K’gari’s Sand Dunes Form?

Sand was carried north along the coast

K’gari’s sandmass developed over millions of years as ocean currents and waves transported sand north from the continental shelf off New South Wales and southern Queensland. The accumulating sand covered much of the underlying bedrock, leaving some higher points exposed as coastal headlands. Wind subsequently carried loose sand inland, forming dunes parallel to the coast and large curved formations farther inland. Changes in sea level created different periods of dune building, leaving overlapping systems of different ages.

An ancient record beneath the forest

Some of K’gari’s dune systems are more than 700,000 years old. According to Queensland Parks, the island and nearby Cooloola preserve the world’s oldest recorded sequence of overlapping coastal dune systems. Newer dunes sit alongside older formations, creating a landscape that records long-term changes in coastal conditions.

A sandblow on K’gari shows how wind-driven sand reshapes the island’s landscape.

Image Credit: Flickr

How Do K’gari’s Travelling Sand Dunes Move?

Sandblows that engulf forests

The island’s most dramatic moving formations are called sandblows. They develop when strong onshore winds break through vegetation and carry loose sand inland from exposed dunes. As sand advances, it can spread over plants, streams and woodland. Queensland Parks reports that sandblows can engulf forests at rates of up to one metre per year. This is a maximum reported rate, not a speed shared by every sandblow. Movement depends on local conditions and the availability of loose sand.

Why vegetation matters

Plants help stabilise dunes by covering the sand and reducing its exposure to wind. When vegetation is damaged by fire, wind, vehicles or foot traffic, loose sand can become mobile and new sandblows may form. Not every dune moves at the same rate. Some are relatively stable under vegetation, while exposed areas can continue to shift. This contrast between anchored forest and advancing sand is a defining feature of K’gari’s landscape.

Lake Waddy is one of K’gari’s distinctive freshwater lakes, set within the island’s shifting sand landscape.

Image Credit: Flickr

Why Does Rainforest Grow on Sand?

Sand is usually poor in nutrients, yet K’gari supports tall subtropical rainforest. The explanation lies in the island’s developing soils, accumulated organic matter and the complex relationship between vegetation and the underlying sand. UNESCO identifies K’gari as a remarkable example of rainforest growing on coastal dunes, including at elevations above 200 metres. Its forests are not growing on bare, newly deposited sand everywhere; rather, they occupy dune systems where soil has developed over time.

An aerial view of K’gari, the world’s largest sand island, off the coast of Queensland, Australia.

Image Credit: Flickr

Coloured Sand Cliffs and Freshwater Lakes

The island’s colourful sand formations

K’gari also has strikingly coloured sand cliffs and exposed sand formations. Rainbow Gorge, also known as Kirrar Sand Blow, is one place where visitors can see the island’s unusual range of sand colours and learn about coastal dune formation.

Perched lakes among the dunes

The island contains freshwater lakes of different types. Perched lakes form when an organic layer of accumulated leaves, bark and other plant material creates a relatively impermeable base above the regional water table. K’gari has 40 perched dune lakes—around half of the world’s total, according to the Australian Government. Lake Boomanjin, which covers about 100 hectares, is a combination of a perched lake and a window lake, where part of the lake reaches the water table.

More Natural Wonders on RiteBook

K’gari is one example of how geology can create unexpected landscapes. Explore the colourful stones of Lake McDonald in Glacier National Park, or read about the remarkable waters of Hanging Lake in Colorado. You can also browse more places under RiteBook’s Natural Wonders label.

Seen from the International Space Station, active white dunes and sandblows contrast with older dune areas covered in vegetation at Sandy Cape on K’gari.

Image Credit: Wikimedia Commons

Conclusion

K’gari’s travelling dunes show that sand is anything but lifeless. Wind continues to push it across the island, burying vegetation and reshaping ancient landforms, while established forests and freshwater lakes thrive on the same sandy foundation. This meeting of geological change and living ecosystems makes K’gari one of Australia’s most remarkable natural landscapes.

References & Sources

• Queensland Parks — Nature, Culture and History
• Queensland Parks — About K’gari
• Australian Government — K’gari World Heritage Place
• UNESCO World Heritage Centre — K’gari
• Queensland Parks — Lake Boomanjin Walk
• Queensland Parks — K’gari Journeys