Early on New Years Eve morning in Minnesota in 1980, a man named Wally Nelson stumbled upon his girlfriend's body lying in the snow just meters from his door.
Nineteen-year-old Jean Hilliard's car stalled as she returned to her parents' house after a night out. Dressed only in a winter coat, mittens and cowboy boots, she stepped out into the night air at minus 30 degrees Celsius (minus 22 degrees Fahrenheit) to ask her friend for help.
At some point, she stumbled and lost consciousness. For six hours, Hilliard's body lay in the cold, the heat left, as a result of which she "froze completely."
“I grabbed her by the collar and dragged her onto the porch,” Nelson told Minnesota Public Radio many years later.
"I thought she was dead. She was as stiff as a board, but I saw some bubbles coming out of her nose."
If it weren't for Nelson's quick reaction, Hilliard could have been one in thousands of hypothermia deaths every year. Instead, her story became part of medical legend and scientific curiosity.
How can a body survive being frozen?
Stories of people surviving freezing temperatures are unusual enough to be news, but not entirely rare either. In fact, medical professionals in countries with cold climates say this: "Nobody is dead until they get warm and die."
The realization that extreme hypothermia is not necessarily the end of life has become the mainstay of therapy in itself. Under controlled conditions, lowering body temperature can cool the metabolism and reduce the body's insatiable hunger for oxygen.
In a medical setting, or on rare occasions elsewhere, a chilled body can slow down the entire dying process long enough to cope with a low heart rate, at least for a while.
Hilliard's story highlights the extreme nature of her hypothermic state.
Forget about the fact that her body temperature barely reached 27 degrees Celsius, which is as much as 10 degrees below the temperature of a healthy person. She was - obviously - frozen. Her face was ashen, her eyes were hard, and her skin was reportedly too hard to pierce with a hypodermic needle.
According to her doctor, George Sater, "the body was cold, absolutely hard, like a piece of meat after deep freezing."
However, after a few hours, warmed by heating pads, Hilliard's body returned to the state of a healthy person. By noon, she was already talking, and soon she was discharged from the hospital to lead a normal life, which was unaffected by the night she spent as a human ice.
Friends and relatives around her believe that all this happened due to the power of prayer. But what is the position of biology on this issue?
Unlike many materials, water in a solid state takes up a larger volume than in a liquid state. This expansion is bad news for body tissues exposed to the cold, as their liquid contents run the risk of swelling to such an extent that they rupture their containers.
Even a few stray ice crystals that bloom in the wrong place can pierce cell membranes with their needle-like shards, turning limbs into blackened patches of dead skin and muscle, or what we usually call frostbite.
Some animals have developed some remarkable adaptations for dealing with the danger of sharp, expanding ice crystals in freezing temperatures.For example, deep sea fish known as Antarctic blacktip icefish produce glycoproteins as natural antifreeze.
The tree frog converts the contents of its cells into syrup, filling the body with glucose, and thus resists freezing and dehydration. Outside of their cells, water freely turns into a solid, enveloping the tissues with ice and making them, by all indications, as hard as ice cubes in the shape of a frog.
With nothing but external observation, it's hard to say for sure how Hilliard's body survived the freeze. Was there something unique about her body chemistry? Or even the composition of her tissues?
Perhaps. A much more important question is what exactly "freezing" means in this case. Despite the low temperature, Hilliard's body temperature was reported to be well above freezing. There is a big difference between metaphorical "chilling to the bone" and literally freezing water in the veins.
The fact that Hilliard's body seemed solid is a common sign of severe hypothermia, as muscle stiffness increases to the point that it may even resemble rigor mortis - rigor mortis that occurs with a dead body.
That the surface of her body was cold and white, and even her eyes seemed glassy and "hard", might not be too surprising either. The body closes the channels for blood vessels under the skin to support the functioning of the organs, so the body looks ashen and remains remarkably cold to the touch.
If medical personnel are persistent enough to try their luck using smaller diameter subcutaneous injections into highly narrowed veins, especially if they are covered with a thin layer of dehydrated skin pressed tightly against stiff muscles, then one might even assume that a couple of needles could be bent as a result.
With virtually nothing but a few surprised tales, we can only speculate whether Hilliard's "frozen" body was typical, shocking, or, on the contrary, unique in its ability to withstand such an extreme change in state. However, there is no doubt that she is lucky.
The more we learn about the amazing capabilities of the human body, the less we can rely on luck to save lives like hers in the future, and more on medical advances and quick responses.