Students at the University of Wisconsin at Madison know a thing or two about snow. Last year, after a blizzard, some of them built an igloo. The same students are at it again this year (see photo above, courtesy of Nate Moll, social media manager at the university).

On Tuesday, Madison announced that it would shut down classes and many other operations after 5 p.m., until Thursday. Colleges and universities such as Madison, which don't shut down for a few flurries, are responding because of projections that temperatures today could go down as far as -50. The University of Chicago will be closed today. So will the University of Illinois at Urbana-Champaign, the Minneapolis Community and Technical College, Lansing Community College and many other institutions. This cold front is wide-reaching -- Georgia State University closed down Tuesday.

Some colleges in some of the coldest parts of the country are not telling students to stay home.

Tim Schroer, associate dean of students at St. Olaf College, said via email that students finished classes for the January term on Tuesday and were ready for finals, which start today. "Life continues to move forward here on campus in spite of -35 looming in the near future," he said.

Schroer shared the photo at right.

On some campuses, students have complained about their administrators not calling off classes as speedily as have other institutions nearby.

Grinnell College will be closed today, in anticipation of dangerously cold air in Iowa. At left, courtesy of Justin Hayworth, a college photographer, a student walking through campus this week.

The University of Michigan announced Tuesday afternoon that there would be no classes held today. But the announcement didn't come until after students circulated a petition criticizing the decision to hold classes Tuesday, specifically noting that severe weather hits some people more than others.

"Our demand: The University of Michigan-Ann Arbor must close campus during harsh weather conditions -- not just in extreme circumstances. A refusal to do so is classist and ableist, with disproportionate effects on workers, low income community members, and community members who are not able-bodied," the petition said.

Purdue University announced Tuesday that it would call off classes on Wednesday. But it also did so after circulation of a petition. One student who signed seemed concerned that President Mitch Daniels should know that while some kinds of freezing are popular with the student body, others are not.

"The tuition is frozen, but I don't want to be," he wrote.

For some colleges, the timing is perfect for a cold front. Rochester Institute of Technology is holding its 2019 FreezeFest, starting Thursday, with ice carving, curling and snowboarding -- plus some indoor activities.

Elsewhere in New York State, Union College's president, David Harris, shot the photo at right of the iconic Nott Memorial, dusted and surrounded by snow.

But of course it is in the Great Plains and Midwest that campuses are currently at the record cold temperatures. Below are a sampling from those institutions.

From Buena Vista University:

From the University of Northern Iowa, photo shot by its geography department's drone:

And from Dakota State University, in South Dakota:

Northwestern University's Martin Tanner sent the following from the Evanston, Ill., campus: