McMurdo Dry Valleys – Antarctic wilderness where no rain has fallen for millions of years

In the heart of Antarctica, in the midst of the land of eternal ice, lies one of the most remarkable places on the planet – the McMurdo Dry Valleys. These are vast, almost snow-free valleys that are considered one of the driest regions on Earth. In some places, rain hasn’t fallen there in millions of years, and conditions resemble the surface of Mars more than any place on our planet.

Why are the McMurdo Dry Valleys so dry?

McMurdo Dry Valleys is one of the driest areas on Earth, despite being located in Antarctica – a continent associated with ice and snow. How is it possible that in a place surrounded by glaciers it almost never rains at all? The answer lies in the unique atmospheric and geographic conditions.

Catabatic winds – natural drying of valleys

One of the main reasons for the exceptional dryness of the McMurdo Dry Valleys is the katabatic winds, which are created when cold, dense air descends from high altitudes and rushes toward the valleys. Imagine it rushing down from the glaciers toward lower-lying areas, just like water. Because it is very heavy and dense, it can reach speeds as high as 320 km/h – a force comparable to a hurricane!

When these extremely strong winds descend into the valleys, they act as a natural dryer – evaporating moisture and drying out the snow before it even has a chance to settle on the ground. As a result, snow and ice do not accumulate in the McMurdo Dry Valleys as they do in the rest of Antarctica, leaving the area almost completely dry.

Rain shadow – a natural blockade for moisture

Another important factor is the so-called precipitation shadow, which can be compared to a huge natural barrier that stops precipitation. In the McMurdo Dry Valleys, this barrier is formed by the Transantarctic Mountains, which separate the valleys from the moist air from over the ocean.

Normally, warm and moist air rises from the sea, condenses and causes rain or snow. But in the case of the McMurdo Dry Valleys, it is trapped by the high mountains, and the moisture falls on the leeward side (that is, where the wind no longer has the power to carry the rain further). The result? Beyond the mountains, that is, in the valleys, it hardly rains at all.

Less rainfall than Atacama desert

The McMurdo Dry Valleys receive less than 100 mm of rainfall per year, less than Chile’s Atacama Desert, which is considered one of the driest places on Earth. It’s as if we collect just a few drops of rain throughout the year – not enough to make puddles, let alone rivers, lakes or even a layer of snow.

Friis Hills – the oldest and most barren place on Earth?

Within the McMurdo Dry Valleys is an even more extreme area – the Friis Hills, which scientists believe may be the oldest and most barren place on Earth.

According to a 2005 study by researchers at the University of Auckland, conditions in the region have remained constant for 14 to as many as 20 million years. This means that this region has not experienced any major climatic changes since the first mammals roamed the Earth!

Why are the Friis Hills even drier than the rest of the valleys?

The Friis Hills are located in the rain shadow of the Transantarctic Mountains. However, unlike other parts of the McMurdo Dry Valleys, they are located higher, which means that even less moisture reaches them.

In addition, the katabatic winds that dry out the valleys have an even more intense effect here, completely evaporating residual moisture. As a result, the rocks and soil remain completely dry, and conditions are so extreme that even the most hardy life forms have difficulty surviving.

The oldest, most barren and most dead?

Scientists studying soil samples taken from the Friis Hills have discovered something surprising – the absence of any signs of microbial life. On Earth, even in the most harsh conditions, in places almost completely devoid of water, it is usually possible to find at least extremophilic bacteria that have adapted to extreme dryness, high salinity or low temperatures. However, no microorganisms were detected in samples taken from the Friis Hills, making this region one of the most inhospitable places on the planet.

Interestingly, however, life does exist in other parts of the McMurdo Dry Valleys. Under the icy crust of the salt lakes, in isolated ecosystems, scientists have discovered microorganisms that have adapted to life without oxygen and light. Thanks to unique metabolic mechanisms, they are able to function in the environment there.

Friis Hills – stopped time

The Friis Hills are one of the few places in the world where you can stand on land that has remained unchanged for millions of years – untouched by time or life. These hills challenge our previous ideas about the limits of life on Earth. Their absolute barrenness shows that there are places where even the most hardy microorganisms could not survive. This discovery is of great importance not only for the study of extreme environments, but also for the search for life beyond our planet. The discovery of minimal needs allows us to better determine where living organisms can still thrive.