A survival expert reacts to 'Society of the Snow' and the true story of how 16 people survived the Andes plane crash

• "Society of the Snow" is based on the remarkable true story of a 1972 plane crash in the Andes.
• For 72 days, 16 people managed to survive, dealing with extreme cold, starvation, and dehydration.

The true survival story behind the Oscar-nominated film "Society of the Snow" is almost unbelievable: After a plane carrying a Uruguayan rugby team and its loved ones crashed in the Andes Mountains in 1972, 16 people managed to survive for 72 days, surrounded by snow and ice.

"It's totally remarkable and possible, but most people would die," Cat Bigney, a survival expert and instructor at the Boulder Outdoor Survival School, told Business Insider.

Most of the 45 passengers and crew who were on the flight did not survive. Some died in the crash, and others in the aftermath.

The film, which is nominated for two Academy Awards, depicts the crash and what followed in striking detail, including the extreme conditions the survivors had to persist through and what they resorted to doing to survive.

"This is more than a movie," Roberto Canessa, who survived the crash at age 19 and consulted on the movie, told Time. "This is an experience we had to share with humanity to show people who are having their own mountain crashes how to be resourceful and how not to give up."

Bigney, who has appeared on survival TV shows and consulted for folks like Bear Grylls, is very familiar with how Hollywood depicts survival stories. She thought the film, directed by Spanish filmmaker J. A. Bayona, was an amazing production and a generally good depiction of what surviving in those conditions would be like.

She explained to BI why surviving in that environment would be so challenging and how 16 people still managed to do it.

Being young and fit would've made a big difference

The first thing that may've helped some of the "Society of the Snow"'s real survivors was something the film did not necessarily show. "The actors that portrayed the rugby team were all very slight. In actuality, the men would've probably had a lot more muscle on their body," Bigney, who also played rugby for over a decade, said.

Many of the plane crash survivors were in their late teens and early 20s. Being young and healthy — and competitive athletes — would've helped them persist in such extreme conditions.

Still, surviving would've been extremely complicated in terms of physiology, Bigney said.

The movie mentioned the well-known "rule of threes" — that humans can generally survive three minutes without air, three days without water, and three weeks without food. But Bigney said that's not necessarily true, especially in the extreme cold when it would be a struggle just to maintain a safe core body temperature.

In order to survive these conditions without the proper gear, Bigney said it would help to fashion makeshift gloves and hats. The real survivors piled on all the clothing they could salvage from the wreckage.

As the movie depicts, the real survivors also fashioned a makeshift shelter out of the plane's fuselage, piling up suitcases and other objects to somewhat enclose the space and block out the wind. While it still would've been cold inside, Bigney said that would've helped.

"They don't have an external heat source to heat up their bodies, but they're minimizing the heat loss from their body," she said. While it still would've been cold inside, blocking the wind would prevent it from continuously blowing away body heat, allowing the body to conserve energy.

Starvation and dehydration made a complicated situation even worse

The survivors' ability to maintain their core body temperature would've been drastically impeded by two other immediate dangers: starvation and dehydration.

Bigney said the body can warm itself up in several ways, like through exercising, eating calories that can be burned, or burning its own reserves. But other than minimal snacks left over from the plane, the survivors did not have access to other food.

"Their bodies are literally self-cannibalizing to keep them alive, so they're losing their muscle," she explained.

With nothing else to eat, the survivors resorted to eating the bodies of the deceased. Bigney said that would calorically provide needed energy, but that they were also likely experiencing nutrient deficiencies, and cannibalism is generally not very nutritious. There are also disease risks associated with eating human flesh, as well as the psychological impact.

"It's just such a horrifying thing, and it's hard to imagine the psychology behind making the decision unless you're forced to do it," she said.

The survivors of Uruguayan Air Force Flight 571 were also dealing with extreme dehydration, despite being surrounded by snow. Eating snow could help somewhat, Bigney said, but it would also require the body to expend additional energy to remain warm.

Melted snow, which the movie shows survivors collecting in leftover water bottles, would help, but it would still be ice-cold. The survivors in the movie and in real life reported that their urine had turned a dark brown color that they even described as "black." Bigney said that could be a sign that "your internal organs really are having a hard time, and most likely due to dehydration."

"If you're putting things in your body but you're not drinking adequate water, it's really difficult for you to digest and get all the toxins out of your body," she said.

Bigney also said that the fact that many of the survivors not only knew each other but were close teammates would've also made a big difference. They would've felt like they could count on each other and already knew how to work together.

Despite all the physical challenges of surviving over two months in those conditions, Bigney said the survivors, most of whom are still alive today, may have struggled even more with the long-lasting trauma.

"I think it's amazing that they've physically recovered, but also psychologically to recover," she said. "I'm sure that the PTSD from that experience and from having to make such a grim choice is something that still lives with them."