A burst pipe at the top floor of the Hall of Graduate Studies Monday evening flooded dozens of student quarters with an estimated 20,000 gallons of water, which sloshed through hallways and stairwells from the top of the building’s tower to its basement.

While less intense on some of the lower floors, the water reached a depth of one to two inches in a number of hallways on and above the sixth floor after spilling out of the building’s flooded elevator shaft, physical plant night plumber Joe Cuomo said. The pipe most likely broke as a result of the low temperature Monday evening, he said.

The water extensively damaged dozens of student rooms, and Graduate School Dean Jon Butler returned to campus from his home in Hamden to help organize the evacuation of several of the tower’s higher floors. Butler said the 35 to 40 students whose rooms were most likely in need of attention from maintenance will be able to stay at the Colony Inn on Chapel Street until repairs to the HGS tower are completed sometime during the next few days.

“Some rooms may have water damage and some may not, but the students will not be able to stay this evening, and probably not tomorrow, either,” Butler said. “We think it will take three days. We’re hoping for two.”

The flooding began when a fire sprinkler pipe burst in the mechanical room on the top floor of the tower and sent water down through the building, said Cuomo, a member of the team that began pumping water out of the HGS basement Monday night. The root cause of the pipe’s explosion had not been determined, but the cold weather was a likely factor, he said.

“Somebody probably left the door open,” Cuomo said.

Butler said a team of fire, police and maintenance workers was able to quickly shut off the water traveling through the tower once they had been alerted to the problem. Officials estimated the pipe burst around 5:45 p.m., but the rupture did not trigger building alarms initially, he said.

Students returned to their rooms hours later to collect their essential belongings and inventory damage after Butler informed them of the arrangements at the Colony Inn. Some students who were in their rooms during the flooding had scrambled to protect their books and papers, but some were too late, Blaise Misztal GRD ’08, a resident of the HGS tower’s eighth floor, said.

“There was a stream of water coming out of the light fixture and a wall of water coming down my bookshelf,” said Misztal, who moved his soaked literature into his bathroom to dry. “I lost a bookshelf’s worth of books. It definitely could’ve been worse, but it was not pleasant.”

Butler said although a pipe had not burst in HGS in years, such things had happened before.

“It’s an old building, built in 1932,” Butler said. “It has never really been renovated, so these things can happen.”

HGS is only the latest Yale building to face water damage caused by burst pipes. The Morse and Ezra Stiles college dining halls were flooded Saturday night after a burst pipe in the Stiles kitchen leaked water into the dining halls and the common room of Stiles. A burst pipe in a Silliman College residential entryway flooded basement space Thursday, and a similar problem in Timothy Dwight College displaced residents in TD’s entryway A.