Off the remote coast of Western Australia, about 1,200 miles north of Perth, entire coral reefs spend most of their lives hidden underwater, rising dramatically out of the sea for a few hours each day.
Known to Aboriginal Australians as Yowjab and more widely as Montgomery Reef, this formation is located in the Kimberley region and is considered the largest inshore coral reef on the planet. As the tide falls, the reef appears to rise directly out of the ocean like a stage being raised to the horizon, an illusion created not by the reef moving but by the water around it steadily draining.
How Montgomery Reef briefly rises above the ocean
The Yugap covers nearly 100,000 acres, according to a fact sheet from Western Australia’s Department of Primary Industries and Regional Development, and can rise up to 26 feet above the ocean’s surface during low tide, says coral biologist Zoe Richards of Curtin University. It’s unmatched by any other reef she knows.
As water cascades off the top of the exposed reef, it flows back into the ocean in dramatic cascades, a sight rarely seen in any other coral formation in the world. This entire transformation usually lasts between two and three hours before the rising tide slowly submerges the reef again.
The unusual biology that holds coral reefs together
Unlike many reef systems built primarily of coral, Yugab owes its structure primarily to coralline algae, which form low ridges along its edges that trap seawater as the tide goes out.
According to Richards, this creates a shifting maze of shallow pools across the top of the reef, where corals, fish, turtles and other marine creatures continue to live even while exposed to the air. Larger animals such as dugongs, crocodiles and sharks retreat to deeper surrounding channels during this period, sometimes waiting up to four hours for the tide to rise again and reconnecting with reef feeding grounds.
Clare Ross, a research scientist at Western Australia’s Department of Biodiversity, Conservation and Attractions, points out that species living on Kimberley reefs have developed a strong resistance to heat stress and frequent exposure to air, conditions that would overwhelm most other coral ecosystems.
A landscape shaped by 1.8 billion years of tidal force
The foundation of the reef is not coral at all, but an ancient mesa made of dolomite and sandstone now covered in coralline algae, a structure dating back approximately 1.8 billion years, according to a fact sheet published by the Australian Department of Climate Change, Energy, Environment and Water. This same geological record describes the wider Kimberley region as having been shaped by some of the world’s largest tides, which can rise as high as 36 feet, carving the region’s valleys, sea cliffs and other unusual formations over an enormous period of geological time.
A marine park managed jointly with its traditional owners
Yowjab is located within Lalang-gaddam Marine Park, one of several marine parks across the Buccaneer Archipelago now managed by the Government of Western Australia along with Aboriginal groups who have called this coastline home for tens of thousands of years. The Dambimangadi people are known as the traditional owners of Yujab and its surrounding waters, and under current co-management arrangements, indigenous rangers monitor biodiversity, track pollution and help protect sites of cultural significance across the region, while also playing an increasing role in guiding visitors through the region’s cultural heritage.
The Dreamtime story behind the reef’s powerful tides
The Yowjab’s dramatic tidal behavior is explained by a Dreamtime creation story associated with the spirit of Wandjina and the rainbow serpent, describing how a grieving mother’s search for her lost son led to the creation of the sea and its violent tidal fluctuations. According to accounts referenced in the same regional fisheries fact sheet, this story remains an important part of Worrora’s cultural heritage directly linked to the reef and the surrounding Kimberley coast.
Separating the Yawijipaya legend from the historical record
Adding to the mystery of Montgomery Reef is a widely circulated story describing the Yawijipaya, an indigenous people said to be up to seven feet tall, who disappeared after being photographed by a French crew in 1929. Australian National University archaeologist Sue O’Connor, who conducted fieldwork on nearby islands during the 1980s, said there was no evidence to support the claim that these people disappeared, suggesting instead that their observed height likely reflects that. Consistent access to protein-rich seafood compared to inland communities.
Drawing on research by anthropologist Norman Tyndale, O’Connor points out that the Yawigibaya people assimilated with mainland Warora communities in the early 20th century rather than disappearing, meaning their descendants remain part of the indigenous population living in the region today.
Why does Montgomery Reef remain a rare natural landscape?
Taken together, Montgomery Reef is notable not only for its size or short daily profile above the waterline, but also for the stratigraphic history embedded in its ancient bedrock, its unusual reliance on coralline algae rather than coral alone, and its deep, continuing connection to the indigenous communities who continue to manage and interpret its waters. Few natural phenomena combine geology, marine biology and living cultural heritage in the same way, making Yugab’s brief daily appearance one of the most truly rare sightings along Australia’s remote northern coast.