A large tree branch collapsed on a group of people during a company picnic at Menlo College on Saturday afternoon, injuring three and sending two to the hospital for treatment, according to the Menlo Park Fire Protection District.

The branch, which was hanging from a heritage oak tree and was about 3 feet in circumference, partially separated from the main trunk at about 2:22 p.m. on Saturday, while hundreds of employees of Riverbed Technologies were attending a company party at the Atherton college campus. The branch landed on a group of about a half-dozen people, hitting one woman on the head and causing abrasions to the body of a 1-year-old child, according to a news release from the fire district.

The woman was treated by paramedics and both she and the infant were taken by an ambulance to Stanford Hospital. A third person suffered minor injuries but declined treatment at the scene.

Moments before the "loud crack," about two dozen adults and children were sitting by the large oak, enjoying its shade. Most had left to engage in an activity just as the branch split off and crashed down on top of those remaining, according to Menlo Fire Capt. Jane Hunt, who responded to the scene about two minutes after the incident was reported.

Fire Chief Harold Schapelhouman said the fire district plans to follow up with Menlo College next week about their tree-safety inspections.

"I know the Fire crews that responded to this incident were extremely relieved that it wasn't much worse than it could have been, given the size of the group and proximity of the seating area under the tree," Chief Schapelhouman said in a news release. "Other similar events have had far worse outcomes and it's something to think about and have checked if you have large trees, given years of drought followed by a winter with such significant rain fall."

Earlier Dumbarton crash, car fire

The incident occurred just minutes after firefighters responded to a collision on the Dumbarton Bridge in which a sedan collided into the back of a 1969 Chevrolet convertible that had stalled near the middle of the span, on the eastbound side. Though the sedan caught fire, no one was injured, fire officials said.

The two women in the sedan were outside the vehicle when firefighters arrived, according to the news release. The owner and lone occupant of the convertible said his car experienced mechanical problems and stalled on the bridge. He was reportedly outside the car and waving at other drivers to warn them of the stalled car when a vehicle narrowly missed his car and changed lanes at the last second. The car following that vehicle crashed into the convertible.

According to the fire district, the man helped both women get out of their car before it caught fire. They said he was relieved they were uninjured but “shaken and unnerved by the experience.” He also said he had bought the car when he was 16 and owned it for more than 40 years, with few problems before Saturday, according to the Menlo Fire news release.

Emergency responders blocked state Highway 84 in both directions so that firefighters could pull the hoses across the lanes and extinguish the fire, according to the news release.