Students divided into two teams based on their dorms, and the snow was flying as they pelted each other.
A couple hundred were at Bascom Hill for the beginning of the melee, but the crowd topped out at a couple thousand or more as the fight ebbed and flowed over the afternoon.
Nineteen-year-old freshman Matt Moertel said his strategy was simply to hurl himself into the opposition.
Some students came holding trays as shields. Others were bundled up to protect themselves from the below freezing temperatures and winds that gusted to more than 20 miles per hour.
Not all were worried about it. Several went shirtless while at least one had on pajamas.
The Associated Press contributed to this report.