PAGE, Ariz. (AP) — A woman and two children have died and two other people remain hospitalized in critical condition after a pontoon boat capsized on Lake Powell in northern Arizona, authorities said Sunday.

National Park Service officials said the privately owned 25-foot pontoon was being towed by another boater when it was overturned by waves Friday afternoon near the mouth of Navajo Canyon within Glen Canyon National Recreation Area.

Lake Powell is located northeast of Page and near the Arizona-Utah border.

Emergency crews responded to the scene and found some of the 11 passengers atop the overturned pontoon and others in the water and trapped underneath the boat.

Glen Canyon rangers and Page Fire Department personnel help get the injured out of the water and into ambulances and helicopters to be rushed to hospitals.

Authorities said Saturday that 72-year-old Melissa Bean and two 4-year-old boys died at the scene.

The names of the boys haven’t been released yet and medical updates for the two injured people weren’t immediately available Sunday.

It remains unclear if any of the victims were related, but authorities said families from Utah and Idaho were on the pontoon when it capsized.

The incident is being investigated by the county sheriff’s department, National Park Service and county medical examiner’s office.

“It’s not unusual for us to investigate a death on the water periodically throughout the year. However, the magnitude of this — we’ve got three fatalities and two in critical condition — is not a common circumstance and it’s definitely tragic,” Lt. Adam Simonsen, a spokesman for the Coconino County Sheriff’s Office, said in a statement.