It's similar to a 100-year flood event. It just doesn't happen that often.
So when it does, students celebrate. That's what happened last night when the University of Michigan called off classes for the first time in 36 years.
The student journalists over at the Michigan Daily collected the best reactions on Twitter to the news.
Here are the best stunned faces, celebratory waffles, and trips to the liquor store:
U-M canceled classes for two days in January 1978 after a 19-inch snowstorm. The Daily reports on how students celebrated back then:
...students threw an outdoor beach party and spent the day lounging in snowdrifts while the theme to "Endless Summer" blared in the background.