The United States Postal Service suspended mail delivery in parts of 10 states in the Midwest on Wednesday in the face of dangerously cold temperatures caused by a polar vortex.
Mail delivery has been suspended in parts of Minnesota, Michigan, Indiana, Illinois, Ohio, Pennsylvania, North Dakota, South Dakota, Nebraska and Iowa.
“Due to the extreme weather conditions caused by Winter Storm Jaden, we have temporarily suspended delivery service in certain locations to ensure the safety and well-being of our employees,” the U.S. Postal Service said in a Facebook post Tuesday night.
In Chicago — where about 80,000 homeless people are facing life-threatening conditions — temperatures plunged to -22° F on Wednesday morning with a wind chills as low as -44° F. Some parts of Minnesota are expected to see temperatures as low as -40° F.
The extreme weather prompted school and office closures, as officials urged people to seek shelter and limit time spent outside.
“A record arctic air mass will remain over the central and eastern U.S. over the next several days,” the National Weather Service tweeted Tuesday. “Wind chill values of 30 to 60 degrees below zero will be common across the northern Plains, Great Lakes, and upper Midwest.”
The cold conditions tested what has come to be known as an unofficial motto of the Postal Service. It appears on a Post Office building in New York City that opened in 1914, though the words date back back to Greek scholar Herodotus in The Persian Wars: “Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds.”
More Must-Reads from TIME
- Why Trump’s Message Worked on Latino Men
- What Trump’s Win Could Mean for Housing
- The 100 Must-Read Books of 2024
- Sleep Doctors Share the 1 Tip That’s Changed Their Lives
- Column: Let’s Bring Back Romance
- What It’s Like to Have Long COVID As a Kid
- FX’s Say Nothing Is the Must-Watch Political Thriller of 2024
- Merle Bombardieri Is Helping People Make the Baby Decision
Write to Katie Reilly at Katie.Reilly@time.com