The polar vortex gripping parts of North America is so cold that the Chicago River and Lake Michigan started steaming.

People across Chicago were treated to the fascinating display with resident Susana Leyva of a giant “40-foot wall of ice steam” on Wednesday.

“Chicago is on lockdown today — ain’t nobody going anywhere!” she wrote. She jokingly referred to Chicago as “Chiberia.”

The steam phenomenon can occur when the temperature of the air is significantly lower than the water or ice.

Fellow Chicagoan Jason Williams also caught the same phenomenon the day before and a video of it happening over the Chicago River, but on a smaller scale. His footage showed wisps of steaming fog rising and flowing across the frigid river.

“Won’t you step into the freezer?” he wrote.

For Canadians hoping to see the “smoking” effect, the polar vortex is expected to brush past the . But seeing the same effect will depend on how cold the air is and how warm the water is.

Polar vortex heading into Maritimes

Over the past several days, people across North Dakota, Missouri, Ohio and Illinois have experienced extreme weather and record-breaking temperatures as the polar vortex makes its way across the region.

Some temperatures dropped to as low as -51 C with the wind chill.

The polar vortex earlier this week was so cold that the Brookfield Zoo in Chicago had to close to ensure the safety of employees and animals – marking only the fourth time the zoo has closed its doors in its 85-year history. Chicago was also one of 10 U.S. states where the U.S. Postal Service has been suspended.

Chicago is expected to be under a wind chill warning until Thursday.

With files from The Associated Press