Harvard University Police will be out in increased numbers to monitor underage drinking during the forbidden annual celebration of Housing Day, known as River Run, that will take place on Wednesday night before freshmen learn their House assignments the next morning.

In past years, students have commemorated River Run with unruly and dangerous behavior, Dean of Freshmen Thomas A. Dingman ’67 said, citing activities such as setting miniature boats on fire in the Charles River.

“We know that the Harvard Police will be out in force and that they have been asked to alert the Cambridge and state police,” Dingman said, calling River Run an “alleged tradition.”

The Crimson reported last year that the River Run festivities, which typically involve consuming large amounts of alcohol in addition to launching flaming crafts on the Charles, began in 2008.

Since 2010, the University has requested increased police presence each year on the night before Housing Day.

Dingman enumerated several reasons for freshmen to remain in the Yard on the perhaps anxious night before they learn their residential assignments but said that underage drinking causes the most concern for administrators.

Recalling the eves of Housing Days past, Dingman said, “People were taking chances and dodging traffic, which almost resulted in fatalities.”

He added, “Cambridge has gotten concerned, so there will be an increased police presence.”

HUPD spokesperson Steven G. Catalano declined to comment on precise staffing numbers, but he wrote in an email that the “Harvard University Police Department will be visible throughout the evening to ensure the safety of all students.”

Dingman said that foolhardy behavior would lead to harsh penalties.

“Should you choose to participate in the ‘River Run,’ be prepared to accept consequences related to your actions, including possible arrest and a case to be heard by the Administrative Board,” Dingman wrote in an email to the freshman class on Tuesday afternoon.

For some freshmen, academic deadlines would act as a deterrent to drinking on Wednesday night, regardless of the increased police presence.

“I have work, so it’s not even a consideration,” said Matt P. Sheets ’15, adding that many of his friend also have midterms this week.

In another measure aimed to prevent drinking, the First-Year Social Committee will host a “Last Night Black Light Dance” in Annenberg from 9 p.m. to midnight on Wednesday.

However, FYSC member and dance co-chair Christopher A. Smiles ’15 said the event is not purely meant to dissuade freshmen from participating in River Run.

“It’s kind of a balancing act. You want to provide a safe but fun alternative to River Run, but you don’t want to just cater to the people who want to do River Run,” Smiles said.

For him, the dance offers the opportunity to unite the Class of 2015 before the freshmen are divided up into twelve House communities.

“One of the big things we’re aiming for in this event is getting everyone together as a freshman class,” Smiles said. “This is our last night together as a class with no divisions.”

—Staff writer Petey E. Menz can be reached at menz@college.harvard.edu.