At least four local law enforcement agencies responded to a series of rowdy student gatherings held at Carson Beach over the Memorial Day weekend. Police estimate that as many as one thousand high school students, from Boston and Somerville, flocked to the beach every day from Friday to Monday, leading to a number of fights, arrests, and disturbances from Savin Hill to Downtown Crossing.

Students took part in the beachside revelry as part of “Skip Day,” an event organized by students through social media websites in order to gain an extra day off, according to police.

State Trooper Brian Dunn said a trio of troopers from the South Boston’s State Police Barracks was first to arrive on the scene on Friday and found “several hundred” students between the ages of 14 and 19 had gathered at the beach.

But the sheer number of students and the lack of any overt criminal activity meant there was little they could do to disperse the crowd before reinforcements arrived. “Basically, you’re outnumbered at least 20 to 1 and you’re trying to balance their right to assemble with everyone’s safety, but once the problem starts it can escalate in a matter of seconds,” Dunn said.

Eventually, Dunn said, tensions between rival groups of students flared when they met on the beach, leading to pockets of fighting and several arrests before the group could be moved out of the area and onto the T.

State troopers called in officers from the Boston Police Department, MBTA Transit Police, UMass Boston’s police department and additional state trooper units to boost their presence and ensure those gathered did not create problems on their way back to the JFK/UMass Station, Residents of Savin Hill, some already on edge because of the murder at the Savin Hill station several weeks ago, reported teens vandalized the area before leaving.

Bill Walczak was coming back from a picnic on Monday and saw a hundred children walking to the T station near the Savin Hill Ave. bridge. Another couple of hundred kids were down at the Savin Hill beach when he dropped by later, with Boston police officers on the McConnell Park side and state troopers on the beach side.

“It was pretty tense,” he said, adding that a police helicopter could be heard circling the neighborhood for a half hour. “They’ve got a serious problem at Carson Beach that spills over onto Savin Hill.”

A similar disturbance occurred last year over the July 4th weekend, which led to the hospitalization of a young boy who was trampled by a crowd fleeing a man whom they believed was brandishing a gun. Following that incident, the city issued a “zero tolerance” statement, declaring the beach off-limits after 11pm.

Walczak said police are more responsive so far. “Last year it was the Fourth of July, and this year it was Memorial Day, and we have a whole summer ahead of us,” he said.

Dunn said police are taking a different tack than last year, minimizing violence by directing teens to the Red Line, and preventing them from moving to another beach and continuing the party.

“The lesson we learned last year is that groups will change venue as soon as we disperse them,” Dunn said. “[Moving teens directly to the T] stopped a lot more problems from happening.”

With the start of summer, law enforcement groups have begun to strategize how to handle similar situations in the coming months, but no plans have been finalized, police said.

News editor Gintautas Dumcius contributed to this report.