Rare Flooding Transforms Australian Desert into Temporary Wetland

Early in 2025, intense rain caused abnormal and life-altering flooding in the heart of the Australian desert. In March, over a year's worth of rain fell in a week, inundating sections of Queensland, flooding Channel Country. Rivers such as Cooper Creek swelled with water, flooding towns and long stretches of pasture before emptying into Lake Eyre, or Kati Thanda-Lake Eyre. When the waters began to recede, satellite images caught an incredible shift in the landscape: once-barren stretches of desert suddenly broke out with green shoots of new life, indicating an eruption of biological activity in a region otherwise defined by aridity.

False-color satellite views from Landsat 9's OLI-2 sensor on April 6 and April 22 put the timeline into perspective. On April 6, Cooper Creek was seen to be full of floodwater below Windorah, where a few of its all-time river records had been shattered. By April 22, the water had retreated away, and vegetation had started growing out of the soggy ground. This went on downstream. On April 10 in the town of Innamincka, river levels exceeded all-time records from 1974. Road access was severed by floodwaters encircling the town, isolating it. Coongie Lakes National Park to the south was shut due to flooding.

On April 28, satellite images from NASA's MODIS instrument on the Terra satellite revealed water covering increasing amounts of Channel Country. The photograph showed Cooper Creek flowing into Strzelecki Creek and finally into Lake Blanche. The creeks are normally dry and fill only during infrequent flood periods. According to records, Lake Blanche filled only six times from 1895-1995. When water does occur, these wetland areas are precious habitat for wetlands that can sustain hundreds of thousands of waterbirds and other plants and animals, so this phenomenon is a requirement to the biodiversity of the area.

The entire hydrological system within this landscape is rivers like Cooper Creek and Diamantina River, all of which feed into the Lake Eyre, the natural lowest point in Australia. Water would normally evaporate or drain into the floodplains before Lake Eyre during any given typical year. Meteorologists do predict 2025's event to fill Lake Eyre most or even full for the first time since over 15 years. The likelihood of full or near-full filling is noteworthy with the lake's rare flooding effect on the regional climatic interaction and ecosystems.

Full-flood Lake Eyre is an inshore sea that is ephemeral which supports water life, attracts birds from right around the continent, and affects local desert climatic conditions on a short-term scale. Such rare floods are not merely a natural process but also offer opportunities for scientific observation, conservation, and community tourism within Australian outback communities. The recent event proves the importance of episodic flooding in arid regions, where this phenomenon maintains 'boom' and 'bust' phases of the environment. Rainy seasons allow wildlife enough time to breed, feed, and survive before the climate returns to dry periods.

The floods have also caused huge disruption to human settlements. Innamincka's isolation is the worst scenario for the disadvantage of outback towns in such floods, where infrastructure is vulnerable and provision with the essentials may be weeks behind. Although the environmental benefits are high, the floods also have the impact of making the value of greater flood preparedness and support facilities for outback towns apparent.

The occurrence of these events was captured by evidence documented by the Operational Land Imager-2 (OLI-2) aboard Landsat 9 and by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra satellite. The band combination used (6-5-4) allows analysts to distinguish between water and vegetation in the satellite imagery. NASA Earth Observatory, which captured these occurrences, partnered with freely available data from the U.S. Geological Survey and NASA EOSDIS LANCE and GIBS/Worldview.

The 2025 Channel Country greening due to drought and the 2025 Channel Country flood remind us of the abrupt change that is driven by weather patterns induced by extreme climatic variability in dryland ecosystems. Researchers notice such extreme change to learn more about the interaction between precipitation patterns and hydrological systems in governing the Australian outback and impacts of these on ecosystems, wildlife migration corridors, and indigenous Australians. Continued satellite monitoring will be crucial to quantify the size of such changes and their frequency of recurrence during the future.

Source/Credits:
NASA Earth Observatory images by Michala Garrison, using U.S. Geological Survey Landsat data and MODIS data courtesy of NASA EOSDIS LANCE and GIBS/Worldview
By Lindsey Doermann
References adopted from ABC (April 11 & April 13, 2025), Kingsford et al., Biological Conservation (1999)