In “Chiberia” – as locals have dubbed Chicago as temperatures have plummeted to -23F (-30C) – it is cold enough to freeze an egg on the sidewalk. Or to turn a bubble blown outside into a beautiful frosty snow globe before it splinters with the cold.

A blast of polar air has swept across many cities in the US leading to the lowest temperatures in a generation. Schools and businesses have closed, flights have been cancelled and as of Wednesday evening, at least eight deaths had been linked to the system.

Chicago isn’t the only city hit by the low temperatures, or the coldest, with the temperature dropping to -42F (-41C) in Park Rapids, Minnesota.

While the extreme cold is miserable for many, some have been trying to find a bright side. In Chicago, residents have posted photographs on social media showing just how freezing life has become.

Local news outlets have made their reporters brave the elements to test whether an egg placed in a frying pan at these temperatures would freeze – the opposite of frying an egg on the sidewalk in extreme heat, which the Guardian Australia team found required hotter temperatures than you might expect.

“Cold as ºF,” was the headline on the Loyola Phoenix, the official student newspaper of Loyola University in Chicago and on Tuesday, the Chicago Tribune ran sage weather-related advice on its front page: “Expert: avoid being outside”.

But many ignored the expert warnings and ventured into the cold to attempt the “boiling water challenge”, which saw people throw pots of boiling water into the air, which froze before hitting the ground.

Others posted videos of bubbles blown outside, which freeze into gorgeous baubles before cracking, or of their fork suspended in mid-air by a waterfall of frozen noodles. The hashtag #DogsofChiberia was created, showing pets rugged up in custom puffer jackets, hats and booties so they could survive a trip outside.

Videos also circulated that appeared to show train tracks across Chicago on fire. The fires, which actually run next to the rails, are used by Metra, the Chicago-area commuter rail, to make the rails expand in an attempt to avoid cracks forming and switches clogging.

Temperatures in Chicago were expected to fall into the -20s F (-30s C) again on early Thursday, but should warm up to the comparatively balmy 20Fs (-7 to -2C) by Friday.