McMurdo Dry Valleys

The short answer

The McMurdo Dry Valleys are a group of largely snow-free valleys in the Transantarctic Mountains of southern Victoria Land, west of McMurdo Sound and the Ross Sea. Wikipedia describes them as the largest ice-free region in Antarctica, about 4,500 square kilometres, and as the coldest and driest desert in the world; precipitation averages about 100 millimetres a year, almost all of it snow. The mountains hold back the ice sheet, and katabatic winds, cold air pouring downhill, strip away much of the snow that does fall. The three main valleys, from north to south, are Victoria, Wright and Taylor. Parties from Robert Falcon Scott’s first expedition, of 1901–04, visited them, and since 1992 Taylor Valley has been a US National Science Foundation Long Term Ecological Research site. Under the Antarctic Treaty the area has been an Antarctic Specially Managed Area, No. 2, since 2004.

Why it's worth knowing

At the snout of Taylor Glacier, where the ice ends in a cliff above the frozen surface of West Lake Bonney, a red stain runs down the ice. The geologist Thomas Griffith Taylor, of Scott’s second expedition, found it in 1911; the valley carries his name. Early explorers put the colour down to red algae. It is not algae.

In 2009 Jill Mikucki and colleagues reported in Science that the water comes from a pool of ancient marine brine beneath the glacier, rich in iron and sulfate and almost without oxygen. Science’s own news report describes it as seawater trapped when the glacier closed off part of a fjord between 1.5 and 2 million years ago, now under about 400 metres of ice. It is not lifeless: the team found a community of at least 17 types of microbes living by cycling sulfur, with iron doing the work that oxygen does for us.

The colour itself was explained more recently. Ken Livi of Johns Hopkins University examined the solids in the water with transmission electron microscopes and found tiny iron-rich nanospheres, about a hundredth the size of a human red blood cell. They are not crystalline, which is why earlier searches for a red mineral missed them. The brine leaves the glacier clear. It turns red only when it meets the air, as its iron oxidises. The study appeared in Frontiers in Astronomy and Space Sciences in 2022, and Johns Hopkins announced it in June 2023.

The field notes

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The valley of the dead, mostly

Scott was not impressed. “We have seen no living thing, not even a moss or lichen,” he wrote, in the lines quoted on the Long Term Ecological Research Network’s pages; “it certainly is the valley of the dead.” He was nearly right. The same pages note that the valleys do hold some moss and lichen, and algae wherever there is liquid water; Wikipedia’s account adds bacteria living inside rocks, sheltered from the dry air, and a 2013 expedition to University Valley that found no living organisms in its permafrost.

Lakes with lids

For a desert, the valleys hold a great deal of water, most of it frozen. Wikipedia counts more than 6,000 lakes and ponds. For a few weeks each summer, glacier meltwater runs down streams such as the Onyx River, which Wikipedia calls Antarctica’s longest river, into lakes with no outlet to the sea, many capped with permanent ice. With nowhere to go, the water grows salty: some of the lakes are saltier than the Dead Sea, and the saltiest of all is little Don Juan Pond, in Wright Valley.

A rehearsal for Mars

The cold, dry ground made the valleys an early stand-in for Mars. Wikipedia’s account says geologists and astrophysicists have used them as a testing ground since NASA’s Viking programme in the 1970s. Blood Falls, with its buried, oxygen-poor brine and its microbes, is studied for what it suggests about life that might survive under the ice of other worlds.

Who may go where

Most of the valleys are open only to science. Within the managed area, protected areas under the Antarctic Treaty can be entered only with a permit; Blood Falls and the lower Taylor Glacier are one of them, Antarctic Specially Protected Area No. 172, designated in 2012 and revised in 2018 and 2023. Tourists and other non-governmental visitors are limited to the Taylor Valley Visitor Zone near the snout of Canada Glacier, a site chosen in consultation with the national programmes working in the area, tour operators and the International Association of Antarctica Tour Operators, and their visits must be coordinated with the national programmes in advance.

A relic from the McMurdo Dry Valleys

Getting there

What to book ahead. Ross Sea voyages are few and long; book as early as the operators allow, and treat a Dry Valleys landing as a hope rather than a promise, since it depends on the weather on the day. The operator arranges the approvals that Antarctic visits require.

Safety. The State Department has Antarctica at Level 2, exercise increased caution, because of extreme and unpredictable weather and limited emergency services, and there are no US consular services there. It recommends travelling with a professional guide or an organisation such as a member of the International Association of Antarctica Tour Operators, and buying insurance that covers medical evacuation.

Common questions

Where are the McMurdo Dry Valleys?

The McMurdo Dry Valleys are in southern Victoria Land, Antarctica, in the Transantarctic Mountains west of McMurdo Sound and the Ross Sea. The main valleys, from north to south, are Victoria, Wright and Taylor. Wikipedia gives their area as about 4,500 square kilometres, the largest ice-free region in Antarctica.

Why is there no ice in the McMurdo Dry Valleys?

The McMurdo Dry Valleys in Antarctica stay largely free of snow and ice because the Transantarctic Mountains block the flow of the ice sheet and cast a snow shadow, so precipitation averages only about 100 millimetres a year, and katabatic winds, dense cold air pouring downhill, strip away much of the snow that falls.

What is Blood Falls?

Blood Falls is a red outflow at the end of Taylor Glacier in the McMurdo Dry Valleys, Antarctica, where iron-rich brine from beneath the ice seeps onto the frozen surface of West Lake Bonney. The geologist Thomas Griffith Taylor found it in 1911. It lies inside Antarctic Specially Protected Area No. 172, designated in 2012.

Why is Blood Falls red?

The brine that feeds Blood Falls in Antarctica leaves Taylor Glacier clear and turns red when its iron oxidises in the air. Ken Livi of Johns Hopkins University found that the colour comes from tiny iron-rich nanospheres, which are not crystalline and so were missed by earlier searches for a red mineral; the study appeared in Frontiers in Astronomy and Space Sciences in 2022.

Is there life in Blood Falls?

Yes. In 2009 Jill Mikucki and colleagues reported in Science that the brine beneath Taylor Glacier in Antarctica, which feeds Blood Falls, holds a community of at least 17 types of microbes living almost without oxygen by cycling sulfur and iron. Science’s news report describes the brine as seawater sealed under about 400 metres of ice for 1.5 to 2 million years.

Can tourists visit the McMurdo Dry Valleys?

Yes, in a limited way. Under the management plan for the McMurdo Dry Valleys, Antarctic Specially Managed Area No. 2, tourists may land only in the Taylor Valley Visitor Zone near Canada Glacier, with visits coordinated in advance with the national programmes. A few Ross Sea expedition voyages carrying helicopters, including Oceanwide Expeditions’, offer such landings when weather allows.

Can you visit Blood Falls?

Not as a tourist. Blood Falls and the lower Taylor Glacier in Antarctica’s McMurdo Dry Valleys form Antarctic Specially Protected Area No. 172, which can be entered only with a permit. Tourist landings in the Dry Valleys are limited to the Taylor Valley Visitor Zone, further down the valley near Canada Glacier.

Are the McMurdo Dry Valleys the driest place on Earth?

Wikipedia describes the McMurdo Dry Valleys in Antarctica as the coldest and driest desert in the world, with average precipitation of about 100 millimetres a year, almost all of it snow. Recorded air temperatures there range from 12.0 °C at Taylor Glacier to −65.7 °C at Lake Vida, by Wikipedia’s account.