Minnesota’s climate, human physiology and social media come together around this time of year to produce a phenomenon we’re going to go ahead and call “frozenface.”

Of course, faces have been freezing for as long as humans have lived in bitterly cold climates. But social media like Facebook and Instagram have elevated frozenface into an art of sorts, with people posting selfies that show off frosty eyelashes, rimy mustaches and beards crusted with actual icicles.

“Look how dad-blasted cold it is, yet I’m smiling,” these portraits say.

It does have to be pretty cold, said Lorentz E. Wittmers, a professor emeritus in physiology at the University of Minnesota Duluth. Frozenface happens when the temperature dips below about 10 degrees (which is why you might not have seen as many in your Facebook feed this year as you did last January).

The other requirement is breath. When you inhale frigid air, the mucous membranes in your respiratory tract warm and moisten it so that when it reaches your lungs it matches your body temperature, Wittmers said.

When you exhale, “the nice wet air that comes out condenses on the cold surfaces that it comes into contact with first,” he said. “If you’ve got a clean-shaven face, it most likely just goes into the atmosphere. If you have facial hair, it condenses on there and then it freezes.”

Those short on facial hair needn’t miss out — a frozen scarf serves as an effective frozenface prosthetic.

The frozenfaces included were all posted on Instagram at #STfrozenface. Feel free to tag your own frozenface. If it ever gets dad-blasted cold enough, that is.