The British explorer Robert Falcon Scott might have survived his ill-fated expedition to the South Pole in 1912 if it were not for a freak cold snap.

Dr Susan Soloman of the US National Oceanic and Atmospheric Administration studied the data

New research published by the Proceedings of the National Academy of Sciences (PNAS) in the US has found Captain Scott and his companions were caught in an unexpected bout of freezing weather.

They died in a tent on the Ross Ice Shelf. "The worst journey in the world," was how a colleague who had wanted to go on the expedition described it at the time.

Capt Scott was just 13 miles (20 kilometres) away from the supplies at one-ton depot which would probably have saved him. He knew this, but Scott and the two men who died with him in that tent were exhausted beyond their limits.

He spent the last few days writing his diary. In it, there is a telling passage: "Our wreck is certainly due to this sudden advent of severe weather which does not seem to have any satisfactory explanation."

Exceptional cold

After the deaths, the expedition's meteorologist remarked that in nine years out of 10 they would have survived, and nobody could have foreseen the exceptionally cold temperatures on the Ross Ice Shelf in 1912.

Many did not believe him, claiming Capt Scott's plan for hauling sleds by hand was inefficient. When he died, Scott had half a sled's worth of rocks collected for scientific study. Critics said half of that weight in seal meat would have saved him.

Scott died in a tent with two others

After a journey of more than 1,500km, Scott was beaten to the pole by a month by the Norwegian Roald Amundsen and his two companions.

Using dogs, they travelled far more easily over the ice. When they returned, by a different route, they weighed more than when they started. The dogs had been their food.

The new study of the weather on the Ross Ice Shelf, only carried out in the past decade or so, shows Scott really was unlucky. He travelled through an exceptionally cold spell, some 20 degrees Fahrenheit colder than usual.

It could have made the difference between life and death.

Modern system

In the early 1980s, scientists began installing a network of automated weather stations, including solid platinum wire resistance thermometers to measure temperature, at remote sites in Antarctica.

It is data from this equipment which US scientists from Boulder, Colorado, and the University of Wisconsin-Madison have compared with the daily temperatures recorded by Scott's expedition.

It is clear the temperatures he experienced were on average 10 to 20 degrees Fahrenheit lower than those obtained in the same region and season since modern measurements began in 1985.

Furthermore, the persistence of cold temperatures recorded in 1912 is unusual, the researchers point out.

Whereas the temperature minimum for all but one day during the three-week period in 1912 was colder than minus 30 degrees Fahrenheit, temperatures for only nine days fall below this mark during the same time period in an average year in the modern record.

Only one year's temperatures in the available 15 years of modern measurements was comparable to that experienced by Scott and his men.

It has been said that in the 1911-12 race to the pole, one man won and the other became a hero.

Almost the last entry in Scott's diary read: "We took risks. We knew we took them. Things have come out against us, therefore we have no cause for complaint."