The 18th annual No Pants Subway Ride streaks across the globe

Lake Harriet in Minneapolis, Minnesota.Image: Kerem yucel/ AFP / Getty Images Parts of the Midwest are experiencing the coldest temperatures in 20 years this week as the polar vortex takes hold.  On Wednesday morning, it was -22 degrees in Chicago, with a wind chill of -49, according to CNN. In northern Minnesota, wind chills dropped to -65. Flights are being delayed and cancelled. The USPS has partially halted service. In some places, it’s possible to get frostbite after only a few minutes of skin exposure. On Twitter, people are sharing the polar vortex’s wild effects in their own hometowns. There’s indoor ice, boiling water vaporizing into the air, innovative winter-wear layering techniques, and (crucially) bundled-up dogs. It’s so cold in …