IStock Photo 1785736 © Tomasz Szymanski

In this season of freezing temperatures, drunk drivers, and judgmental in-laws, drowning might not top most people’s list of winter threats. But everyone’s favorite buttress against the cold—booze—makes sure that drowning isn’t just for sorrows.

College towns in northern states like Wisconsin know the phenomenon well. A student gets wasted at the bar and then falls into a river or other chilly body of water while trying to get home. Once in the water, alcohol in the blood temporarily slows down the production of blood sugar, leading to the deadly double hypo—hypoglycemia and hypothermia. This makes the already drunk student disoriented and weak, left without the energy needed to get out of the water.

The overall odds of a person dying by drowning in a year, 1 in 83,650, are roughly the same as the odds of getting injured by hazardous weather, 1 in 85,440. The odds of drowning in a natural body of water are much lower, 1 in 185,800. And the odds of falling into water and then dying by drowning are much lower still: 1 in 719,700, roughly on par with the odds of being injured by a tornado, 1 in 739,600, and just slightly more likely than dying by falling off of a ladder, 1 in 746,600.

While falling into a river and drowning may not be a common way to die, binge drinking doesn’t help the situation. The odds a person 18-25 will binge-drink alcohol in a month are 1 in 2.43, meaning that roughly 41% of people in this age range consume five or more alcoholic drinks in a single setting. These are roughly the same odds that an undergraduate will receive non-federal financial aid in a given year: 1 in 2.45.

So when a young college student turns up drowned in the local river, last seen at the bar, it would be easy to blame the booze—but some parents who have lost children this way have a far more sinister explanation. Law enforcement officials have found a signature mark in the places where at least some of the students who have died this way fell—or were forced—into the water. A smiley face at or near the scene of the crime suggests to some that a serial killer or network of serial killers may be at work.

A pair of retired detectives say that they have found this grim calling card at dozens of sites in the last decade. Deaths in Ohio, Wisconsin, Iowa, Pennsylvania, and New York fit the pattern. While there are no leads, and the theory remains just a theory for the time being, the so-called Smiley Face Killer could give college kids a good reason to make a New Year’s resolution to drink in moderation.

It may be tempting to believe that incompetence is more likely than conspiracy, especially when it comes to drinking and drowning, but one final fact begs a second thought:

The odds a person will be murdered in a year are 1 in 18,690—over four times more likely than dying by drowning.