As temperatures dropped well below zero Monday, city and county officials warned residents to be cautious of the deadly cold.

“These are life-threatening temperatures,” a Dane County statement warned.

A city statement urged residents to keep several days supply of water and food on hand in case subzero temperatures prevented them from leaving the house.

According to the city, Madison saw a series of closures Monday, including public health clinics, due to the cold. Dane County also issued a series of warnings and alerts to the extreme windchill.

Meanwhile, a Storify from Channel 3000 showed some local residents found a way to have fun in bitter situation, testing to see if water thrown outdoors would immediately turn to ice. Spoiler alert: It does.

A tweet from Chelsea Bliefernicht of Watertown, Wis. read: “Going outside to throw water in the air and watch it freeze. Because what else do you do during a #polarvortex?”

https://twitter.com/cbliefernicht/status/420381076201037824

See what happens when I throw a thermos of boiling water into the frigid air in Madison: http://t.co/lVX7m7ONo5

— Rep. Mark Pocan (@RepMarkPocan) January 6, 2014

At 9 p.m., the temperature in Madison was 14 degrees below zero. According to a Dane County alert, local temperatures could drop to -45 degrees overnight and into Tuesday morning.

[Photos by Chris Lotten, The Badger Herald]