Rita Chrétien's ability to survive seven weeks on water, trail mix, candy and little else is probably thanks to common sense, quick thinking and a lot of luck.
She didn't have survival training, she wasn't a camper or a hiker - she was just, as long-time friend Dave Goertzen puts it, a "quiet, strong" 56-year-old woman who somehow knew to keep as still, hydrated, warm and dry as possible as she waited 49 days to be rescued.
The human body is designed to work toward homeostasis, compensating for extremes in temperature and environment by internal shifts. But if you're exposed to the elements and deprived of nutrients for extended periods of time, there are only so many ways to cope.
Extreme temperatures cause the body to use up as much as 10 times the amount of energy it normally would just by shivering in an attempt to stay warm. Get wet and you lose body heat 25 times faster than you would while dry.
By expending as little energy as possible, the body can eventually slow its own metabolism in a starvation environment - but you still need a basic calorie count to survive (this basal amount is around 600 calories but can be anywhere from 500 to 1,000, depending on body type, the amount you're moving and the temperatures to which you're exposed).
Once caloric intake drops below that bare minimum, the body starts to feed on itself - metabolizing first its own fat, then its muscle stores in order to keep going. The very act of melting snow to drink uses up body heat and, in turn, scant energy stores.
It isn't uncommon for people to be stranded in the North American wilderness. But not everyone makes it: Lorne Greenway, chief executive officer of the Wilderness Medical Society in Utah, can name in a space of minutes people he knows - a friend in a pickup bed last year, another friend's elderly parents - who didn't survive that isolation.
The Chrétiens' biggest mistake, in this case, experts say, was for Albert Chrétien to leave the vehicle to seek help. Such action is only warranted in dire circumstances, says Oregon doctor Gene Allred - in the case of severe injury, for example, or if you're close to a major highway and know how to get there.
Another mistake was not telling people their planned route: For an extended period of time, rescuers were searching in an entirely different location, much closer to where the couple was last seen.
In Ms. Chrétien's case, however, luck and her wits were on her side: She had safe groundwater and, miraculously, was able to last on what little food she had.
"She was probably pretty debilitated when they finally got to her," Dr. Greenway said. "But she did survive."
March 19, early morning: Rita and Albert Chrétien leave their home in Penticton, B.C., en route to a trade show in Las Vegas.
March 19, late morning: They cross the U.S. border near Osoyoos, B.C. Mr. Chrétien calls his friend Dave Goertzen to tell him where they are, and that he's turning off his phone. That's the last call made on Al's cell.
March 19, around 2:40 p.m.: The couple is captured on camera buying snacks in a gas station in Baker City, Ore. This is to be their last known sighting by anyone for almost two months.
March 20: This is the approximate date the couple is believed to have found their van stuck in the mud after having taken what they thought was a scenic detour.
March 22: This, according to Ms. Chrétien, is the day Mr. Chrétien left with the GPS in search of help.
March 29: When the couple doesn't return on the expected date, it raises alarm bells for friends and family.
March 30: Missing-person report is filed.
May 6: A group of hunters in all-terrain vehicles comes across Ms. Chrétien in the couple's vehicle. She's severely weakened, but alive.